AN EVALUATION OF THE COAL BED METHANE POTENTIAL OF THE MID-ZAMBEZI AND NORTHEASTERN KALAHARI KAROO BASINS By Johannes Hermanus Jacobus Potgieter Dissertation submitted in fulfilment of the requirements for the degree of MASTER OF SCIENCE In the Faculty of Natural and Agricultural Sciences Department of Geology University of the Free State Bloemfontein South Africa 2017 Internal Supervisor: Prof. W.A. v.d. Westhuizen External Supervisor: Dr. L. Nel DECLARATION I declare that this thesis is my own, unaided work. It is being submitted for the degree of Master of Science in the Department of Geology, University of the Free State, Bloemfontein. This thesis has not been submitted previously for any degree or any examination at any other University. __________________________________ Johannes Hermanus Jacobus Potgieter This __________ day of ________________ , 2017 “Do or do not, there is no try” - Jedi Master Yoda ABSTRACT With the growing energy demand worldwide it is very important to identify any new fossil fuel resources for future use. Coal remains the most widely used fossil fuel for electricity generation in Southern Africa but over the past two decades gas has been seen as a possible supplement and ultimate replacement for the coal. A lack of world class conventional gas accumulations in Southern Africa, unconventional gas deposits, hosted in the Karoo Supergroup, have been investigated as an alternative gas source. The primary unconventional resource focussed on in north-eastern Botswana and north-western Zimbabwe to date has been coal bed methane (CBM), a natural gas generated during the coalification process and stored within internal coal structures. A major limiting factor for a regional investigation into the CBM resource potential is the lack of exploration information specifically focussed on gas rather than coal. The gas saturation state of coal has a notable impact on the measureable gas content value as well as the production potential within an area. One of the assumptions of previous semi-regional assessments was that the coal is fully saturated, which has not been the case from dedicated gas exploration campaigns in the region. As part of this evaluation the coal ranks, obtained from historic borehole data over the study area, were compared to the laboratory measured maximum sorptive capacities to determine the theoretical gas content of the coal. Investigations of two regional analogous coal fields showed that the coals are unlikely to be fully saturated and for a resource evaluation based on coal rank it is imperative to use a range of saturations for the final data inputs. Schlumberger’s GeoX software was used for a probabilistic resource calculation using Monte Carlo simulations with ten thousand iterations. The resource estimation results showed a wide distribution of probable values. Even with a resource value of 22Tcf, the major basins in Canada and the US have significantly higher resource densities than that of the Study Area indicating a lower prospectivity for CBM. Key words: Coal bed methane, Coal, Saturation Kalahari Karoo Basin, Mid-Zambezi Basin, Karoo Supergroup, Wankie, Nata. ACKNOWLEDGEMENTS I would like to thank the following people and institutions who were all instrumental in the completion of this investigation: • Dr. Alexei Milkov for introducing me to the world of volumetric evaluations and the statistical modelling of regional data investigation. • Juan Botillo for your patience, guidance and motivation during my early days of resource evaluation. • Neil Andersen for introducing me to the Karoo and CBM. • Dr Leon Nel for his guidance through the review process. • Prof. Willem van der Westhuizen for your calls and mails that got me back on track when I let my mind wander onto other matters. • Sasol Limited for the financial backing and access to GeoX during the completion of the dissertation. • All the field exploration teams that have for the past 120 years endured many hardships and epic travels to give us the information that we use every day of our geological lives. TABLE OF CONTENTS 1. INTRODUCTION 1 1.1. Gas as an Alternative Energy Source to Coal 1 1.2. Study Aim 5 1.3. Evaluation Methodology 5 1.4. Study Area 6 2. COAL BED METHANE AS AN UNCONVENTIONAL RESOURCE 7 2.1. Coal bed methane Generation, Storage and Migration 7 2.2. Coal Bed Methane Production 10 2.3. The Importance of the Gas Saturation State of Coal 13 2.4. Coal Bed Methane in Southern Africa 15 3. REGIONAL GEOLOGICAL SETTING 17 3.1. Development and Preservation of the Karoo Supergroup 23 3.1.1. The Karoo in Botswana and Zimbabwe 26 3.2. Karoo Supergroup in the Study Area 32 3.2.1. The Pre-Ecca Formations 37 3.2.2. Ecca Formations 38 3.2.2.1. Lower Ecca Formations 38 3.2.2.1.1. Botswana 38 3.2.2.1.1.1. Tswane Formation 39 3.2.2.1.1.2. Mea Arkose Formation 40 3.2.2.1.2. Zimbabwe 42 3.2.2.2. Upper Ecca Formations 44 3.2.2.2.1. Botswana 44 3.2.2.2.1.1. Northeastern Botswana 44 3.2.2.2.2. Zimbabwe 46 i 3.2.2.2.2.1. Wankie, Entuba and Western Areas Coalfields 46 3.2.2.2.2.2. Lubimbi Coalfield 47 3.2.2.2.2.3. Sengwa Coalfield 47 3.2.2.2.2.4. Gokwe Coalfield 48 3.2.2.2.2.5. Tjolotjo, Sawmills, and Insuza Areas 48 3.2.2.2.2.6. Upper Wankie Sandstone Formation 49 3.2.2.2.2.7. Tshale Formation 50 3.2.2.2.2.8. Ridge Sandstone Formation 50 3.2.3. The Post-Ecca Formations 51 3.2.3.1. Botswana 51 3.2.3.1.1. Tlhabala Formation 53 3.2.3.1.2. Lebung Group 54 3.2.3.2. Zimbabwe 57 3.2.3.2.1. Madumabisa Mudstones 57 3.2.3.2.2. Escarpment Grit 57 3.2.3.2.3. Pebbly Arkose Formation 58 3.2.3.2.4. Forest Sandstones 58 3.2.3.3. Volcanic Rocks in the Study Area 58 3.3. The Post-Karoo Sediments 61 4. COAL DEVELOPMENT AND CHARACTERISTICS IN THE STUDY AREA 71 4.1. Coal Quality and Rank 75 4.2. Coal Thickness, Depth and Regional Continuity 80 5. ASSESSMENT OF THE CBM RESOURCE OF THE STUDY AREA 83 5.1. Area 86 5.2. Coal Thickness 86 5.3. Coal Density 87 5.4. Gas Content 90 ii 5.4.1. Hydrocarbon Generation Potential of Coal 93 5.4.2. Estimation of the Gas Content of the Coal in the Study Area 97 5.4.3. The Impact of Gas Saturation Levels within the Coal Seams 109 5.5. Resource Evaluation 117 6. CHALLENGES WITH DATA ACQUISITION AND MITIGATION MEASURES FOR FUTURE EXPLORATION 122 6.1. Data to be Acquired During Exploration Programmes 122 6.2. Guidelines for CBM Exploration Data Collection, Sampling and Reporting 123 6.2.1. Programme Planning and Logistics 125 6.2.1.1. Drilling Techniques 125 6.2.1.2. Desorption Equipment 126 6.2.1.2.1. Desorption Canisters 126 6.2.1.2.2. Canister Spacers 128 6.2.1.2.3. Water Baths and Hot Boxes 128 6.2.2. In-Field Sampling 129 6.2.2.1. Sampling Strategy 130 6.2.2.2. Sample Identification and Collection 130 6.2.3. Gas Content Measurements 134 6.2.3.1. Measureable Gas 134 6.2.3.2. Lost Gas 138 6.2.3.3. Residual Gas 141 6.2.3.4. Total Gas Content 142 6.2.4. Wireline Logging 144 6.2.5. Post-Desorption Sample Analyses 147 6.2.5.1. Basic Analyses 147 6.2.5.2. Specialised Analyses 147 6.2.6. Data Reporting 152 iii 7. SUMMARY 154 8. CONCLUSIONS 158 9. RECOMMENDATIONS 159 10. REFERENCES 160 11. APPENDICES 171 iv LIST OF FIGURES Figure 1 The geology of conventional and unconventional hydrocarbons (Armaretti, 2014). 2 Figure 2 Projected contributions of specific hydrocarbon sources to the fossil fuel energy pool (U.S. Energy Information Administration, 2011). 3 Figure 3 Petroleum exploration and production activities in South Africa with the Waterberg CBM (blue) and Karoo shale gas (red) projects highlighted (after Petroleum Agency of South Africa, 2015; Dowling, 2006 and Shell, 2012). 4 Figure 4 Location of the study area superimposed onto a Google Earth image. 6 Figure 5 The coalification process (Alberta Energy, 2012). 7 Figure 6 Flow dynamics in coals (Al-Jubori, et al., 2009). 8 Figure 7 Coal cleat geometries (Laubach, et al., 1998). 9 Figure 8 Methane adsorption in coal cleats and pores (Flores, 2002). 10 Figure 9 CBM extraction methods. 12 Figure 10 The effect of saturation on the production from a CBM well (after Aminian, 2005 & Crain, 2015). 14 Figure 11 Locations of the areas previously assessed for CBM potential. 16 Figure 12 Permian basins of southern Godwana. 18 Figure 13 Geological time scale (Walker, et al., 2012). 19 Figure 14 The study area (red polygon) superimposed onto the Karoo basins of Southern Africa, (after Catuneanu, et al., 2005). 20 Figure 15 Location of the Smith (1984) and Anglo Coal Botswana (2010) boreholes in North East Botswana superimposed onto the SRTM image (after National v Aeronautics and Space Administration, 2006; Smith, 1984 and Anglo Coal Botswana, 2010). 22 Figure 16 Major structural provinces and tectonic units of Botswana (Potgieter & Andersen, 2012). 24 Figure 17 Ice flow directions in the Kalahari Karoo Basin (Jansson, 2010). 25 Figure 18 Simplified Pre-Karoo basement of Botswana (after Geological Survey Department, 1984). 27 Figure 19 Distribution of the Karoo basins and formations in Botswana (after Smith, 1984). 28 Figure 20 Distribution of the Karoo Supergroup in North East Botswana (after Smith, 1984). 29 Figure 21 Cross section of the postulated Nata Sub-Basin (after Smith, 1984). 29 Figure 22 The descriptive subdivisions of the Mid-Zambezi Basin as used by Oesterlen & Lepper (2005). 31 Figure 23 Boreholes that intersected the lower Karoo formations in north-eastern Botswana, superimposed onto the outline of the Kalahari-Karoo and Mid- Zambezi Basins after (Anglo Coal Botswana, 2010; Pitfield, 1996; Mothibi, 1999 and Persits, et al., 2011). 33 Figure 24 Southwest–northeast trending cross-section of correlation of the Karoo lithostratigraphic units through the Aranos, Kalahari, Mid-Zambesi and Cabora Bassa basins with the study area stratigraphic correlation highlighted (Catuneanu, et al., 2005). 34 Figure 25 Distribution of the Upper and Lower Karoo across the study area (after Mothibi, 1999; Pitfield, 1996 and Persits, et al., 2011). 36 Figure 26 Location of the Smith (1984) and Anglo Coal Botswana (2010) boreholes in Botswana. 41 vi Figure 27 Stratigraphy of the lower Karoo Supergroup in the Mid-Zambezi Basin in Zimbabwe (after Thompson, 1981; Moyo, 2012 and Oesterlen & Lepper, 2005). 43 Figure 28 Distribution map of the Late Carboniferous-Early Jurassic Karoo Supergroup in the Kalarhari Karoo Basin of Botswana showing the regional divisions of the basin, the borehole localities and palaeo-current directions in the coal-bearing Ecca Group (Bordy, 2009). 46 Figure 29 Postulated depositional environments of the coal bearing formations in the Mid-Zambezi Basin (Oesterlen & Lepper, 2005). 49 Figure 30 Lower Lebung Group distribution throughout Botswana Bordy, et al. (2010)b. 56 Figure 31 Location of the major Karoo igneous unit throughout Southern Africa (Jourdan, et al., 2004). 60 Figure 32 Map of African Karoo flood basalts, sills, and related dyke swarms (Jourdan, et al., 2005). 60 Figure 33 Isopach and distribution of the Kalahari Group (Haddon & McCarthy, 2005). 62 Figure 34 Representative borehole logs from different locations across the Kalahari basin (Haddon & McCarthy, 2005). 63 Figure 35 Map of Botswana showing the location of the Makgadikagi Pans (SA-Venues). 65 Figure 36 Lake Paleo-Makgadikgadi levels (Himmelsbach, et al., 2008). 68 Figure 37 Neotectonism of Lake Paleo-Makgadikgadi (Himmelsbach, et al., 2008). 69 Figure 38 Lake Palaeo-Makgadikgadi extents and bounding ridges (Partridge & Maud, 2000). 70 Figure 39 Coal occurrences in Southern Africa with the basins of interest highlighted (Cairncross, 2001). See Table 8 for a brief description of the coal occurrences. 72 vii Figure 40 Investigation areas and regions used in this evaluation. 74 Figure 41 Alteration of peat into coal (Kentucky Geological Survey, 2011). 76 Figure 42 Coal types and uses (World Coal Institute, 2005). 76 Figure 43 Graphical differentiation of coal constituent distributions, based on proximate analysis (constructed after Krishan, 1940; Middelkoop, 2009 and Cardott, 2012). 78 Figure 44 The Wankie Main Seam (k2-3) lithofacies changes at the Wankie Concession (Oesterlen & Lepper, 2005). 81 Figure 45 A typical vertical section through the Wankie Main Seam, Zimbabwe (Cairncross, 2001). 81 Figure 46 Shangani Energy exploration and production grants in Zimbabwe showing the test location from which CBM was produced (Maponga, 2014). 83 Figure 47 Location of the study area showing investigation areas in Zimbabwe, exploration boreholes in north- eastern Botswana and the Kubu Energy boreholes. 85 Figure 48 Extent of the mapped Karoo Supergroup in the study area (after Pitfield, 1996; Mothibi, 1999 and Persits, et al., 2011). 86 Figure 49 Distribution of total coal thickness data. 87 Figure 50 Formation density logging tool and compensated density log indicating coal seams. 88 Figure 51 Distribution of densities from the compensated density logs of all values less than 1.75g/cm³ collected from 9 coal exploration boreholes in Botswana (after Kubu Energy, 2014). 89 Figure 52 Investigation areas in Zimbabwe and boreholes in Botswana used in this evaluation (after Thompson, 1981; Palloks, 1984; Smith, 1984; Oesterlen & Lepper, 2005; Barker, 2006 and Anglo Coal Botswana, 2010). 92 viii Figure 53 Correlation of maturity and coal type (Corrado, et al., 2010). 94 Figure 54 The temperature transformation of kerogen with increased depth and temperature (McCarthy, et al., 2011). 94 Figure 55 Coal rank classification based on maturity, moisture content, volatile matter content and heating value (Smith, et al., 1994). 95 Figure 56 Relative gas production amounts from coal in selected Australian basins (Faiz, et al., 2012). 96 Figure 57 Simplified elevation cross-section across the Kubu area showing the encountered coal seams and dolerite intrusions (Faiz, et al., 2013). 98 Figure 58 Langmuir isotherm parameters (IHS Inc., 2014). 101 Figure 59 Relationship between rank, depth, and sorptive capacity (Eddy, et al., 1982). 104 Figure 60 Digitised trend lines of the relationship between rank, depth, and sorptive capacity after Eddy, et al. (1982). 105 Figure 61 Correlation between the Langmuir isotherm and Eddy, et al. (1982) trend line equation gas content values. 106 Figure 62 Desorption testing results from Zimbabwe (Barker, 2006). 110 Figure 63 Digitised gas contents from the Shangani Energy measurement data graph compared to the maximum sorptive capacity (after Barker, 2006 and Eddy, et al., 1982). 111 Figure 64 Evaluations of the Permian coals collected during the Kubu Energy exploration campaign in Botswana (Faiz, et al., 2014). 112 Figure 65 Gas measurement data from the Shangani graph plotted on theoretical sorptive capacities of a high ix volatile bituminous A coal type (after Barker, 2006 and Eddy, et al., 1982). 113 Figure 66 Distribution of gas content values from the calculated, digitised and measured datasets. 116 Figure 67 Distribution of the results of the GeoX Monte Carlo resource calculation. 120 Figure 68 Well stratigraphy and coal measure zonation as used in the guidelines. 124 Figure 69 Coring sizes (Sandvik Mining and Construction, 2015). 125 Figure 70 Test sample canister (Stoeckinger, 1991). 127 Figure 71 Clamp type aluminium HQ3 canisters (Potgieter, 2015). 127 Figure 72 Water bath (GEO Data, n.d.). 129 Figure 73 Desorption canisters in a water bath (Waechter, et al., 2004). 129 Figure 74 Desorption sample collection strategy. 131 Figure 75 The wireline coring system collection mechanism (Massenga Drilling Rigs, n.d.) 133 Figure 76 Sample identification and collection (CBM Asia Development Corporation, 2012) 133 Figure 77 Coal sample selected for desorption on digital scale (Potgieter, 2015) 133 Figure 78 Desorption canister with purge and thermocouple valve (GEO Data, n.d.) 133 Figure 79 Single sample desorbed gas content measuring apparatus (Weatherford Laboratories, n.d.). 135 Figure 80 Continuous multiple sample desorbed gas content measuring apparatus (CSG Exploration & Production Services, n.d.). 135 Figure 81 Cumulative measureable desorbed gas curve (Faiz, et al., 2013). 136 Figure 82 IsoTube gas sampling receptacle (Fieldwork Group, n.d.). 138 x Figure 83 Curve fit lost gas estimations (Waechter, et al., 2004). 139 Figure 84 Comparison of linear and polynomial fits in a coal with high gas content and high diffusion rate over a 4.4 hour period (Waechter, et al., 2004). 140 Figure 85 Core slabbing equipment (GeoGas Pty Ltd, 2016). 141 Figure 86 Residual gas content measurement milling canister (Weatherford Laboratories, n.d.). 142 Figure 87 Residual gas mill pot in a shaker (GeoGas Pty Ltd, 2016). 142 Figure 88 Desorption summary sheet (Kubu Energy, 2014). 143 Figure 89 Examples of wireline logging units. 146 Figure 90 Hypothetical production dynamics of 2 coal types and similar depths. 148 Figure 91 Isotherm sample selection. 150 Figure 92 Example of desorption and coal data over a heterogeneous sampling zone. 151 xi LIST OF TABLES Table 1 Corner coordinates of the study area. 6 Table 2 Lithortratigraphic subdivisions of the Karoo Supergroup in the Mid-Zambezi Basin (Oesterlen & Lepper, 2005). 30 Table 3 Correlation of the Karoo Supergroup formations in the Ellisras (Lephalale), North East Botswana and Northern Belt and Mid-Zambezi basins. 35 Table 4 The Post-Ecca Formations across the study area. 51 Table 5 Karoo stratigraphic units Upper Karoo in Southern Africa (Catuneanu, et al., 2005). 52 Table 6 Stratigraphic nomenclature of the Lebung Group used in this study with relation to Green (1966), Smith (1984), Anglo Coal Botswana (2010) and Bordy, et al., (2010)b. 55 Table 7 Attempted correlation of the Kalahari Group stratigraphy across the basin (Haddon & McCarthy, 2005). 64 Table 8 Main characteristics of the coal occurrences shown in Figure 39 after, (Cairncross, 2001; Sparrow, 2012 and Barker, 2012) 73 Table 9 Coal classification properties on ash free basis (constructed after Krishan, 1940 and Cardott, 2012). 77 Table 10 Coal ranks across the study area derived from ash- free proximate analyses. 79 Table 11 Minimum, maximum and average coal thicknesses and top depths from borehole records. 82 Table 12 CBM recovery factors for three North American plays. 84 Table 13 Summarised statistics of all total coal thickness values across the study area. 87 xii Table 14 Summarised statistics of density values less than 1.75g/cm³ obtained from the Kubu Energy (2014) wireline logs. 89 Table 15 Data sources and types used throughout this evaluation. 91 Table 16 Kerogen types as determined by visual kerogen analysis, origin, and hydrocarbon potential (SPE UGM SC, 2014). 93 Table 17 Selection parameters and thresholds. 99 Table 18 Subset of samples used in the gas content evaluations. 100 Table 19 Data evaluation of the select Kubu samples (after Kubu Energy, 2014). 103 Table 20 Trend line equation calculations derived from the sorptive capacity graphs by Eddy, et al. (1982). 105 Table 21 Langmuir isotherm and Eddy, et al. (1982) trend line equations gas content calculations for the Kubu sample subset. 107 Table 22 Calculated gas contents for the coal seams using the trend line equations based on the coal qualities and depth. 108 Table 23 Summarised statistics of the gas content data digitised from the Shangani Energy measurement data graph (after Barker, 2006). 110 Table 24 Coal saturation levels of the Kubu data subset (after Kubu Energy, 2014). 114 Table 25 The effect of gas saturation state of the coal on the calculated gas content data using the trend lines derived from Eddy, et al. (1982). 115 Table 26 Summarised statistics measured, digitised and calculated gas content values with incorporating the effect of saturation levels of the coal. 116 Table 27 Summary of original and filtered data inputs used in GeoX. 118 xiii Table 28 Summary of the inputs used in GeoX. 119 Table 29 Result of the GeoX volumetric resource calculation showing the P10, P50, Pmean and P90 values. 120 Table 30 Resource densities for the basins used in this (after APF Energy, 2004). 121 Table 31 Aspects addressed as part of the guidelines for CBM exploration data collection and sampling. 123 Table 32 Sampling sequence of events. 132 Table 33 Suggested desorption measurement intervals (Potgieter, 2015). 137 Table 34 Wireline logging tool specifications and logging speeds (Farr, 2012). 145 Table 35 Proposed coding library for CBM exploration borehole, sampling and analysis information. 153 xiv LIST OF EQUATIONS Equation 1 Ash-free content estimation formulae (Snyman, 1998). 77 Equation 2 Calculation of gas in place volumes (Aminian, 2005). 83 Equation 3 Determination of gas content from a Langmuir isotherm (IHS Inc., 2014). 102 Equation 4 Determination of dry, ash-free gas content from a Langmuir isotherm (IHS Inc., 2014). 102 Equation 5 Determination of dry, ash-free gas content (after Snyman, 1998). 102 Equation 6 Resource density calculation method. 121 LIST OF APPENDICES Appendix A Schedule of borehole data, indicating coal depth and thickness used in this study. 172 Appendix B Schedule of borehole data, indicating coal quality and coal rank estimated from the ash-free fixed carbon, volatile matter and moisture values used in this evaluation. 180 Appendix C Schedule of borehole data showing the Gas Content Calculated from the Eddy, et al. (1982) trend line Equations used in this evaluation. 196 Appendix D List of isotherm samples collected and analysed by Kubu Energy (after Faiz, et al., 2013). 205 Appendix E Gas content values from the Shangani Energy exploration data digitised from the Barker (2006) graph. 207 xv 1. INTRODUCTION According to the World Coal Association (2010) coal is still the most widely used energy source worldwide and accounts for approximately 41% of electricity generation. With South Africa’s coal resources diminishing and political instability in Zimbabwe, Southern African exploration activities are primarily being focused on Southern Botswana and Mozambique. However, the quality of coal in Wankie is of great importance as there is an economic coking grade fraction in the succession (Sable Mining Africa Ltd, 2011). Any extension of this coal province into the politically more stable Botswana is of cardinal economic importance to Southern Africa. 1.1. Gas as an Alternative Energy Source to Coal This growing energy demand coupled with finite coal supply has resulted in industry leaders identifying and investigating new energy sources for future use. According to Origin Energy (2015) natural gas is an important transitionary fuel during the period where reliable, affordable, safe and low-carbon alternatives to coal and nuclear sources are investigated. In North America natural gas is being used extensively as the preferred energy source for domestic use and is one of the cleanest fossil fuels used for electricity generation (Alberta Energy, 2008). One trillion cubic feet (Tcf) of natural gas is capable of supplying a 1000MW power station with fuel for approximately 20 years (Rycroft, 2014). Currently there are two primary types of gas resources being exploited (Figure 1). Conventional gas resources, hosted in highly permeable sandstone reservoirs that can be reached with traditional well-drilling techniques (Origin Energy, 2015). Unconventional gas resources are exploited from formations with much lower permeability such as shale and siltstone, and is very technology driven (Armaretti, 2014). The most well-known of the unconventional gasses is Shale Gas that gained notoriety as a result of the completion method known as fraccing, also referred to as fracking, hydraulic fracturing or hydraulic stimulation. Another unconventional resource, currently being exploited in North America and Australia, is coal bed methane (CBM) where deep coal seams are exploited and gas produced. 1 Figure 1 The geology of conventional and unconventional hydrocarbons (Armaretti, 2014). Southern Africa has very few producing conventional gas fields, mostly off-shore South Africa and Namibia. Currently the only commercially producing onshore field is in Mozambique, operated by Sasol. Worldwide the number of conventional fields being discovered continues to decline year on year. As a result of this, unconventional gas resources have in the past two decades, became much more important in the global energy market and so too in Southern Africa. Forecasts show that shale gas and CBM could account for up to 56% (Figure 2) of the United States energy pool (U.S. Energy Information Administration, 2011). The vast marine shales of the Main Karoo Basin, in South Africa, and coal fields in Southern Africa have been the focus of these exploration efforts. The most notable programmes are the Waterberg CBM near Ellisras, operated by Anglo Coal (Dowling, 2006) and planned Karoo shale gas project, operated by Shell (Shell, 2012), in South Africa (Figure 3). The coal fields of north-eastern Botswana and north-western Zimbabwe, for their CBM potential, will be the focus of this evaluation. 2 Figure 2 Projected contributions of specific hydrocarbon sources to the fossil fuel energy pool (U.S. Energy Information Administration, 2011). 3 Figure 3 Petroleum exploration and production activities in South Africa with the Waterberg CBM (blue) and Karoo shale gas (red) projects highlighted (after Petroleum Agency of South Africa, 2015; Dowling, 2006 and Shell, 2012). 4 1.2. Study Aim This study aimed to evaluate the CBM resource potential within the study area with respect to the gas in place (GIP) CBM volumes. GIP values are one of the criteria to determine exploration success. 1.3. Evaluation Methodology The evaluation of available borehole information over the area of interest with respect to key aspects of coal and CBM exploration, formed the basis of the study. The most accurate geological information was obtained from historic borehole logs and published reports. For this study, a detailed examination of all available published information was completed as the primary source of data. Parameters that were extracted are coal quality, gas content measurements, stratigraphic depths and nett coal thicknesses, determined from geological borehole logs. It was not possible to view any core as the mudstones of the Karoo Supergroup tend to weather very quickly if not stored properly. This deterioration affects both the geological description and made correct depth correlation impossible. The regional geological continuity and correlations were determined from existing literature and supplemented by drilling records derived primarily from Anglo Coal Botswana exploration operations from 2008 to 2010 (Anglo Coal Botswana, 2010). The review of the data included an investigation into the nett thickness of the coal in the region. During the evaluation the rank of the coal and gas generation and holding capability was established and combined with gas saturation measurements taken from analogous fields in the region. These datasets were used as inputs to the GIP calculations in GeoX. For comparative purposes the resource evaluation results were compared to a number of other basins globally. 5 1.4. Study Area An area with a surface extent of 166 931 km² covering the north-eastern part of Botswana and the north-western part of Zimbabwe was selected as the focus for this study (Table 1 and Figure 4). The study area covers portions of the Kalahari Karoo and Mid Zambezi Karoo Basins. Table 1 Corner coordinates of the study area. Corner Latitude Longitude West 19°15'22"S 23°49'18"E North 16°19'41"S 27°16'29"E East 18°27'4"S 29°32'53"E South 21°26'57”S 26°13'48"E Figure 4 Location of the study area superimposed onto a Google Earth image. 6 2. COAL BED METHANE AS AN UNCONVENTIONAL RESOURCE Coal Bed Methane (CBM) is the term used for the natural gas that is generated by thermogenic alterations of coal or by biogenic action of indigenous microbes on the coal (Simpson, 2008). CBM along with shale gas are the two most prominent unconventional gas resources currently being exploited. An unconventional source is defined as a natural gas source where the source rock acts as the reservoir with no or very little gas migration. These unconventional plays are often associated with very low permeability and porosity. 2.1. Coal bed methane Generation, Storage and Migration Thermogenic methane is generated during the coalification process (Figure 5) when organic debris is deposited in swamps, swamp-like lakes and overbank levees where peat is formed. As the peat is buried deeper it changes to brown coal, lignite, bituminous coal and ultimately anthracite depending on the pressure and temperature the coals are exposed to. During this process the decomposition of the organic material produces methane gas which along with other gases, including nitrogen and carbon dioxide, is adsorbed in the coal (Alberta Energy, 2012). Biogenic methane is generated by microbial activity post coalification under anaerobic conditions to produce methane (Faiz, et al., 2012). The generation capability of biogenic methane is very difficult to measure or predict. Biogenic enhancement has, however, been investigated as a possible reservoir enrichment technique (Fallgren, et al., 2013). Figure 5 The coalification process (Alberta Energy, 2012). 7 CBM is often not pure methane but a mixture of gasses of with the most prominent three being methane, nitrogen and carbon dioxide. During economic evaluations of small scale projects the understanding of the gas composition of the CBM is essential. Carbon dioxide is corrosive and requires specialised completion and reticulation equipment whereas nitrogen is thermally inert and can be seen as the equivalent of ash in coal. Gas composition changes are often localised and inconsistencies in sampling procedures could have significant effects on the gas content values (Potgieter, 2015). The majority of the gas (>95%) in coal is stored in micropores that are estimated to have diameters ranging from 0.5 to 1 nm (Laubach, et al., 1998). These small diameters mean the coal matrix has little to no effective porosity. The cleat-fracture porosity in coal to be between 0.5 and as much as 2.5% and is regarded as the primary conduits for flow and migration (Figure 6). The remainder of the gas in the coal is free gas that exists in fracture systems (Laubach, et al., 1998). Figure 6 Flow dynamics in coals (Al-Jubori, et al., 2009). 8 Cleats are natural opening-mode fractures that usually occur in two sets that are mutually perpendicular and also perpendicular to bedding in coal beds (Laubach, et al., 1998). These cleats account for most of the permeability and much of the porosity of CBM reservoirs and can have a significant effect on the stimulation and production of a reservoir (Laubach, et al., 1998 and Flores, 2002). Figure 7 illustrates coal cleat geometries (a) depicts cleat-trace patterns in plan view and (b) cleat hierarchies in cross-section view. These conventions used for cleat measurement are: • LENGTH is parallel to cleat surface and parallel to bedding • HEIGHT is parallel to cleat surface and perpendicular to bedding • APERTURE is perpendicular to fracture surface • SPACING between two cleats of the same set is a distance between them at right angles to the cleat surface (Laubach, et al., 1998) Face and butt cleat systems are the primary and secondary permeability fractures, respectively, used by gas and water flows in the coal. Methane molecules are adsorbed along the surfaces of these cleats and related porosity by weak van der Waals bonds (Flores, 2002), Figure 8. Figure 7 Coal cleat geometries (Laubach, et al., 1998). 9 Figure 8 Methane adsorption in coal cleats and pores (Flores, 2002). Coal Bed Methane Production In the United States, CBM has been produced commercially since the mid 1970’s when operators started to modify existing petroleum industry technology. This led to a new branch of unconventional reservoir enhancement and production techniques such as long reach, shallow horizontal drilling and multi stage hydraulic fracturing (Hollub & Schafer, 1992). One limitation that did exist was that conventional oil and gas technology did not always work, mainly because the geology of the coals differed from that of conventional oil and gas deposits (Hollub & Schafer, 1992). Formation water that saturates the coal provides the hydrostatic pressure to hold the CBM in an adsorbed state (Dowling, 2006). Only when this hydrostatic pressure is reduced will the gas molecules be capable of being desorbed (Figure 9). Dewatering reduces the hydrostatic pressure and promotes gas desorption from coal (Al-Jubori, et al., 2009). The production of gas is governed by the rate at which gas desorbs from coal. The permeability of the gas-water system in the cleat network and 10 stimulated fractures controls the flow of gas through the beds (Al-Jubori, et al., 2009) and (Laubach, et al., 1998). Once the dewatering is ceased and the hydrostatic pressure returns to normal production will cease too. Gas producing coal seams with no water have been discovered and commercially exploited. In these reservoirs, the adsorbed gas is held in place by free gas in the cleats. Consequently, gas production consists of both free gas from the cleat system and desorbed gas from the matrix (Al-Jubori, et al., 2009). The CBM capability of the Bowen Basin in Australia is regarded as world class and will act as the main feeder for the Australia Pacific Liquefied Natural Gas (APLNG) Project in Queensland (Australia Pacific LNG, 2011). 11 a) CBM extraction showing the hydrostatic pressure cone of depression (Montana Bureau of Mines and Geology, n.d.) b) CBM production and associated water production using a separator from a vertical well in Australia (Australia Pacific LNG, 2011) Figure 9 CBM extraction methods. 12 2.2. The Importance of the Gas Saturation State of Coal The saturation state of a coal seam is determined by comparing the measured gas content to the maximum sorptive capacity of the coal. The maximum sorptive or gas holding capacity of the coal is measured in a laboratory by isotherm analysis (Eddy, et al., 1982; Stoeckinger, 1991 and Faiz, et al., 2013). In an area where measured gas content, permeability testing and isotherm data is available the saturation state information is used to determine the production dynamics of an asset (Swindell, 2007). CBM production is associated with the simultaneous abstraction of water from the coal seam. The pumping of water reduces the hydrostatic pressure in the reservoir resulting in unassisted flow of gas from the production well. Aminian (2005) demonstrated that the ratio between the produced water and gas at different times of the life of a well is determined by the saturation. A saturated coal seam will produce gas nearly simultaneous to the initiation of the water pumping, whereas there is a long period of water abstraction required prior to any gas production in under-saturated seams. The instance where the hydrostatic pressure has been reduced sufficiently to start the production of gas from the coal seam, is referred to as the critical desorption pressure (CDP). Once the well has been depressurised to a point where no gas and only water is abstracted, it is plugged and abandoned. This point is known as the abandonment pressure (AP) (Crain, 2015). Under-saturated coal seams have a shorter production life than wells with saturated coals (Figure 10). 13 Figure 10 The effect of saturation on the production from a CBM well (after Aminian, 2005 & Crain, 2015). 14 2.3. Coal Bed Methane in Southern Africa The primary target for these unconventional resources in Southern Africa is the Karoo Supergroup, specifically the Ecca Group for its terrestrial coal and marine shale deposits as possible CBM, shale gas and conventional hydrocarbon source rock targets (Hiller & Shoko, 1996; Segwabe, 2008; Potgieter & Andersen, 2012 and Faiz, et al., 2014). According to Catuneanu, et al. (2005) the Karoo Supergroup in north-eastern Botswana is structurally, depositionally and sedimentologically controlled, and the uniform continuation of the Mid-Zambezi Basin into Botswana. The deposition is limited to a small localized sub-basin, the Nata sub-basin, as described by (Smith, 1984). Taking Oesterlen & Lepper (2005) into account, CBM as well as some minor shale gas plays can be hosted by the Karoo Supergroup. The CBM resources in Botswana and Zimbabwe have been regarded as potentially exploitable gas deposits and over time, a substitute for coal as the primary energy source in the region. Current convention is that terrestrial deposits are likely to host coal resources and marine shale deposits are considered to be prospective for shale gas (Boyer et al., 2011). To date there has been a great deal of speculation on the size of the potential resource, with values ranging from as high as 27Tcf in just the Hwange/Lupane Fields (Mukwakwami, 2013) to values as low as 0.2Tcf for the Lupane-Binga area (Mthandazo, 2015). Sibanda (2015) reported resource values of 40Tcf in Lupane- Lubimbi (Figure 11). The resource estimation values are often based on either proprietary data or single point datasets that have been extrapolated to fit a regional study area (Potgieter, 2015). Currently there are no commercially producing CBM fields in Southern Africa. However, Anglo Coal has had exploration success in the Waterberg Basin in South Africa with a pilot production study commencing in 2004 (Dowling, 2006) while Tlou Energy plans to commence their full scale pilot study on Central Botswana in 2015/2016 (Tlou Energy, 2014). 15 Figure 11 Locations of the areas previously assessed for CBM potential. One of the major limitations noted with previous CBM resource evaluations was the lack of compensation for lower saturations. In a number of the existing evaluations full saturation levels were presumed (Potgieter, 2015) as opposed to lower saturation values noted in a number of exploration assessments by Faiz, et al. (2014) and Rainbow Gas and Coal Exploration (Pty) Ltd, (2011) in Central Botswana. The change in assumed saturation has a notable effect on the CBM resource potential across the study area and will be addressed in this evaluation. 16 3. REGIONAL GEOLOGICAL SETTING The study area is underlain by formations ranging from the Precambrian to Cenozoic ages. The main focus of the study was the formations of Palaeozoic and Mesozoic rocks of the Karoo Supergroup (Figure 13). The Carboniferous to Jurassic ages of the Karoo Supergroup are highlighted by the red shaded blocks. The Karoo Supergroup is appreciated for both its geological value and for its variety of well-preserved animals and plant fossils. The well preserved fossil records of the Karoo provide distinct indications of the climate, ecology, fauna and flora of the Permian and Triassic times (Potgieter & Andersen, 2012). The term Karoo Supergroup refers to sedimentary basins which occurred as the result of a major inversion tectonic event along the southern margin of Gondwana (Figure 12) during Late Carboniferous times (Catuneanu, et al., 2005). Sedimentation in these basins continued until the Middle Jurassic, around 178Ma, when widespread basalt flows and mafic dyke and sill intrusions occurred across the super continent Gondwana (Jourdan, et al., 2004). For this study, the focus area will be the northeastern part of the Kalahari Karoo Basin in Botswana and Mid-Zambezi Basin in Zimbabwe as indicated on Figure 14. Green (1966); Smith; (1984), Catuneanu, et al. (2005) and Modie (2007) postulated that the north-eastern portion of the Kalahari Karoo Basin extend eastwards into the Mid-Zambezi Karoo basin in Zimbabwe where the Wankie coal field is one of the most important coal deosits in Southern Africa (Figure 14). This extension led explorers and the Botswana Geological Survey to believe that the North East Botswana basin has a high potential of hosting economic coal deposits (Cairncross, 2001). 17 a) Reconstruction of Pangaea (McCarthy & Rubidge, 2005) b) The ongoing accretion tectonics in the foreland basins along the southern margin of Gondwana during the late Palaeozoic (Adelmann & Fiedler, 1998) Figure 12 Permian basins of southern Godwana. 18 Figure 13 Geological time scale (Walker, et al., 2012). 19 Wankie Coal Field Figure 14 The study area (red polygon) superimposed onto the Karoo basins of Southern Africa, (after Catuneanu, et al., 2005). 20 In the study area, the Karoo is poorly exposed and only a few outcrop descriptions could be made by Green (1966). The stratigraphic descriptions by Smith (1984) were mainly obtained from limited deep boreholes drilled by Shell Coal and Anglo Botswana Coal in the 1970’s aided by a deep resistivity survey by Shell Coal (Smith, 1984). The most complete drilling records through the coal measures in north- eastern Botswana are from the Dukwi area. For correlation and formation identification purposes this area was used as the stratigraphic analogue by Smith (1984). This was however, subjective, as at the time of the correlation very little deep Karoo beds were intersected in the boreholes north of Nata and the correlation with the condensed Karoo beds around Dukwi proved to be extremely tentative (Smith, 1984). As a result of the increased CBM interest in Botswana since the publication of the Advanced Resources International, Inc. (2003) report on the CBM and shale gas potential of the Central Kalahari Basin, a number of companies applied for prospecting licences (PL). Anglo Coal Botswana (ACB) was the most notable contributor to additional deep level drilling in north-eastern Botswana. A total of twelve exploration boreholes were drilled by ACB over 23 PLs from 2007 to 2009 (Figure 15), to further delineate the lower Karoo strata north of Nata. The coordinates for the ACB exploration boreholes were obtained from the Anglo Coal Botswana (2010) relinquishment report submitted to the Department Geological Surveys and the historic borehole coordinates were obtained by georeferencing and orthorectifying the maps by Smith (1984). 21 Figure 15 Location of the Smith (1984) and Anglo Coal Botswana (2010) boreholes in North East Botswana superimposed onto the SRTM image (after National Aeronautics and Space Administration, 2006; Smith, 1984 and Anglo Coal Botswana, 2010). 22 3.1. Development and Preservation of the Karoo Supergroup The development of the Kalahari Karoo Basin began in the late Carboniferous times to early Permian and was mainly influenced by tectonics and climate. The tectonic development of the Kalahari Karoo Basin is not well documented but there is evidence of rejuvenation of faults related to the Zoetfontein Fault (Figure 16) and a series of uplift and sagging events over the interior of the basin (Potgieter & Andersen, 2012). Le Gall, et al. (2002) found that one of the mafic dykes from the Okavango Dyke Swarm (ODS) yielded a minimum age of 883 ± 4 Ma. This dyke was chemically distinct (low-Ti tholeiite) from the other ODS dykes, showing that the ODS contains both Proterozoic and Jurrassic dykes (Potgieter & Andersen, 2012). This indicates that the failed rift (triple junction) as postulated by Jourdan, et al. (2006) probably propagated an ancient zone of weakness. The tectonic regimes in the study area vary from predominantly flexural systems in the south related to the subduction, accretion and mountain building processes along the Panthalassan (Palaeo-Pacific) margin to predominantly extensional regimes, related to the spreading of the Tethyan margin, in the north of Gondwana (Catuneanu, et al., 2005). Further to the tectonic influences, the regional climate changes had a notable control of the stratigraphic deposition from cold, semi-arid environments in the Late Carboniferous to increasingly warmer climates with fluctuating levels of precipitation (Catuneanu, et al., 2005). The most recent glaciations in Africa lasted from 302Ma to 290Ma and during the maximum glaciations the South Pole was located in Southern Africa. This glacial advance occurred in a number of phases starting north of the Polar Regions and moving towards the tropical latitudes resulting in approximately 150Ma of major climatic change prior to the final ice sheet retreat (Catuneanu, et al., 2005 and Jansson, 2010). This retreat led to deposition of sedimentary rocks that record a change in geological environment from glacial cool, moist conditions during which the Dwyka Group sediments were deposited (Jansson, 2010). Figure 17 shows the minor and major ice-flow directions in and around the Kalahari Basin controlled by changes in topography or differences in deglaciation between ice sheets. 23 Figure 16 Major structural provinces and tectonic units of Botswana (Potgieter & Andersen, 2012). 24 Figure 17 Ice flow directions in the Kalahari Karoo Basin (Jansson, 2010). During the Permian period organic-rich postglacial sedimentary rocks were deposited in lacustrine, deltaic and fluvial environments (Johnson, et al., 1996). The rocks of the Permian is suggestive of tundra-type peat bog deposition caused by a northward shift of Africa from polar to sub-polar regions (Segwabe, 2008). Prograding deltas caused the formation of extensive plains capable of suppuration stable vegetation growth (Segwabe, 2008). The Permian deposits in the Kalahari- Karoo basin comprise fluvio-deltaic sands, muds and peat (Smith, 1984; Segwabe, 2008) The Beaufort Group strata, deposited from the late Permian to middle Triassic, consist dominantly of mudstones and siltstones with lenticular and tabular sandstones deposited by a variety of fluvial systems (Potgieter & Andersen, 2012). There was a gradual change in the mechanism responsible for the sedimentary deposits from flexural subsidence to extensional tectonics which took place during the Beaufort (Potgieter & Andersen, 2012). 25 A significant tectonic event ended the Beaufort sedimentation, as depicted by the base-Molteno angular unconformity which is developed in many basins where it can be seen overstepping the older Karoo units onto basement rocks (Potgieter & Andersen, 2012). The rocks of the Molteno Formation were deposited by large braided rivers. A climate change resulted in the formation of the Red Beds of the Elliot Formation in South Africa. Continued global warming led to increasing aridification with the deposition of regional aeolian sandstones widely referred to as cave sandstones (Catuneanu, et al., 2005; Potgieter & Andersen, 2012 and Palloks, 1984). Sedimentation in the Karoo Basin was terminated abruptly approximately 180 Ma ago when the crust ruptured and large volumes of basaltic lava flowed out covering virtually the whole of southern Africa. These eruptions heralded the breakup of Gondwanaland and occurred mainly from long crack-like fissures through which the magma welled. Lava flows were typically between 10m and 20m thick, and flow after flow erupted building up a pile of lava over 1 600m in South Africa, but usually not more than 400m in Botswana and Zimbabwe (Potgieter & Andersen, 2012;, Jones, et al., 2001 and Jourdan, et al., 2004). The magma that did not reach the surface was injected under pressure into the sedimentary layers of the Karoo rocks crystallizing to form dolerite sills. These vary in thickness from a few centimetres to more than 100m (Jourdan, et al., 2004 and Rainbow Gas and Coal Exploration (Pty) Ltd, 2011). Magma also solidified in the fissures producing dolerite dykes. This Karoo Volcanic event was very short lived, lasting only about 2 million years. The Okavango Dyke Swarm, formed a prominent feeder to the magmatic event in Botswana (Jourdan, et al., 2005 and Potgieter & Andersen, 2012). 3.1.1. The Karoo in Botswana and Zimbabwe The Karoo Supergroup in north-east Botswana overlies the Ghanzi-Chobe foldbelt to the north and west of the basin. This foldbelt is believed to be a palaeotopographic high onto which the Karoo sediments onlapped during sedimentation (Smith, 1984). This onlapping nature of the Karoo Supergroup was noted in a number of the boreholes reported by Anglo Coal Botswana (2010). As shown on Figure 18 north- eastern Botswana is underlain by Archaean Basement that is represented as a ridge, 26 south of Dukwi. This ridge has been postulated by Smith (1984), Green (1966) and Stansfield, (1973) to have affected the Karoo sedimentation and is generally regarded as the southern limit of the North East Botswana Karoo Basin. Figure 18 Simplified Pre-Karoo basement of Botswana (after Geological Survey Department, 1984). 27 a) Spatial distribution of the Karoo basins in Botswana. b) Formations of the Karoo Supergroup – This study will focus on the Northern Belt of the Central Kalahari and North East Botswana basins. Figure 19 Distribution of the Karoo basins and formations in Botswana (after Smith, 1984). 28 29 Figure 20 Distribution of the Karoo Supergroup in North East Botswana (after Smith, 1984). Section Location shown on Figure 20 Figure 21 Cross section of the postulated Nata Sub-Basin (after Smith, 1984). The Karoo Supergroup was deposited in a number of basins in Zimbabwe (Table 2) of which the Mid-Zambezi is economically the most prospective basin as it hosts the world famous Wankie and Entuba coal deposits (Thompson, 1981; Palloks, 1984 and Sable Mining Africa Ltd, 2011). The search for coal in North West Zimbabwe dates back to 1894 with the discovery of the Wankie coal deposits which has delivered an abundance of geological exploration data (Palloks, 1984). Table 2 Lithortratigraphic subdivisions of the Karoo Supergroup in the Mid-Zambezi Basin (Oesterlen & Lepper, 2005). The Wankie Black Shale and Coal unit of the Ecca Group has been studied in great detail as a result of the economic potential of the coal seams in the region as well as the postulated hydrocarbon potential as investigated by Hiller & Shoko (1996) and CBM exploration companies such as Afpenn, Lupane Gas and Shangani Energy. Thompson (1981) described the Wankie Black Shale and Coal, hosting the most economic coal seams, as the formation directly underlying the Madumabisa mudstones and overlying the Lower Wankie sandstone. In their re-evaluation of the 30 Wankie Black Shale and Coal, Oesterlen & Lepper (2005) confirmed the findings of Duguid (1986) that the drilling records of the Wankie coalfield and other areas in the basin showed great lithological variability within the unit. As a result of this variability Oesterlen & Lepper (2005) defined the basin in a number of subdivisions as shown in Figure 22. Figure 22 The descriptive subdivisions of the Mid-Zambezi Basin as used by Oesterlen & Lepper (2005). 31 3.2. Karoo Supergroup in the Study Area All boreholes drilled by Anglo Coal Botswana (2010) were terminated in the basement. An onlap of the upper Karoo onto the Precambrian Basement was noted towards the north-east with the lower Karoo being absent in all but 4 of the wells (Anglo Coal Botswana, 2010) (Figure 23). Catuneanu, et al. (2005) showed a correlation between the Mid-Zambezi and North East Botswana Karoo Basins (Figure 24). In this correlation it was indicated that the formations of the Karoo are correlatable with some minor adjustments to formations noted in Botswana. These adjustment can be attributed to both thinning of the deposits and/or lack of regional drilling data in Botswana. The study is focused on the Ecca Group coal measures and this stratigraphic unit was isolated as an individual unit and correlated across the study area. For ease of reference the formations described were correlated with the Ellisras (Lephalale) basin in South Africa. This correlation is shown in Table 3 along with the informal nomenclature that was used for the identification of the units of interest during this evaluation. • The “Pre-Ecca Formations” comprise the Dwyka Group equivalents; • The “Ecca Formations” hosting the coal measures encompasses all coal bearing formations hosted in the Ecca Group equivalents. Further subdivided into the Upper and Lower units and; • The “Post-Ecca Formations” comprises all formations from the top of the Ecca to the Jurassic volcanic formations. 32 Figure 23 Boreholes that intersected the lower Karoo formations in north-eastern Botswana, superimposed onto the outline of the Kalahari- Karoo and Mid-Zambezi Basins after (Anglo Coal Botswana, 2010; Pitfield, 1996; Mothibi, 1999 and Persits, et al., 2011). 33 Figure 24 Southwest–northeast trending cross-section of correlation of the Karoo lithostratigraphic units through the Aranos, Kalahari, Mid-Zambesi and Cabora Bassa basins with the study area stratigraphic correlation highlighted (Catuneanu, et al., 2005). 34 Table 3 Correlation of the Karoo Supergroup formations in the Ellisras (Lephalale), North East Botswana and Northern Belt and Mid-Zambezi basins. PERIOD EPOCH GROUP ELLISRAS BASIN NORTH EAST BOTSWANA MID-ZAMBEZI BASIN THIS STUDY* AND NORTHERN BELT OF THE CENTRAL KALAHARI BASINS FORMATION Letaba Formation Stormberg lava Group Batoka basalt JURASSIC Early Clarens Formation Ntane Formation Forest Sandstone Formation STORMBERG Pebbly Arkose Formation Late Lisbon Formation GROUP Fine red marly sandstone TRIASSIC Mosolotsane Formation Ripple marked Flagstone Middle Greenwich Formation POST-ECCA FORMATIONS Escarpment Grit Early Upper Madumabisa Mudstones BEAUFORT Eendragtpan Formation Tlhabala Formation GROUP Middle Madumabisa Mudstones Late PERMIAN Lower Madumabisa Mudstones Upper Grootegeluk Formation Tlapana Formation Upper Wankie Sandstone ECCA GROUP Black shale and Coal Group ECCA FORMATIONS Early Mea Arkose Formation Lower Swartrand Formation Lower Wankie Sandstone Tswane Formation Wellington Formation PRE-ECCA FORMATIONS CARBONIFEROUS Late DWYKA GROUP Dukwi Formation Dwyka glacial Beds Waterkloof Formation Sources Bordy, et al., (2010)a; Catuneanu, et al., (2005); Smith, (1984); Anglo Coal Botswana, (2010); Bordy, et al., (2010)b; Palloks, (1984); Thompson, (1981) and Oesterlen & Lepper, (2005) * The nomenclature will be used for this study for the combination of units into chronostratigraphic equivalents across the study area 35 LOWER KAROO UPPER KAROO Figure 25 Distribution of the Upper and Lower Karoo across the study area (after Mothibi, 1999; Pitfield, 1996 and Persits, et al., 2011). 36 3.2.1. The Pre-Ecca Formations All glaciogenic sediments of the Dwyka Group in Botswana were grouped into a single formation known as the Dukwi Formation by Stansfield (1973). Smith (1984) noted the presence of this formation in two boreholes drilled near the town of Dukwi, ACB intersected the glacial sediments of the Dukwi Formation in 5 boreholes. The base of this formation is regarded as the sediments unconformably overlying the Precambrian Basement and the top is taken as the youngest beds with glacial characteristics (Smith, 1984). Drilling records show that the formation consists of a lower member approximately 16m thick, comprising a tillite with siltstones and sparse pebbly siltstones (Stansfield, 1973). A re-evaluation of the sediment descriptions by Smith (1984) suggested that they are more likely to be proglacial, water lain deposits rather than true glacial debris deposits. The 3 m upper member encountered comprises varved siltstones and mudstones with a thin conglomerate towards the top of the member. Smith (1984) found that during the early Dwyka Group times an ice sheet moved in a south-westerly direction from central Botswana which coincides with the minimal striation records available along the Molopo River. A basal tillite was deposited beneath this ice sheet and thickens in basement depressions. Smith (1984) proposed that the pockets of tillite or reworked till were deposited on an uneven pre- Karoo surface and was subsequently overlain by glaciolacustrine sediment deposits. Green (1966) showed that variations in the sedimentation rates were related to palaeoclimatic effects of glacial retreat. This theory is supported by the “patchy” nature of the formation specifically in the eastern regions suggesting that the primary under-sheet process was that of erosion. It was postulated that the Precambrian basement formed a topographical high and that the current Dwyka Group distribution is close to the original depositional extent (Smith, 1984). Glacial tillite deposits of the Dwyka Group have been noted in many parts of the Mid- Zambezi basin, predominantly from exploration drilling records. Thompson (1981) refered to the glacially deposited formations as the Lubimbi Glacials of the Dwyka Series, whereas Oesterlen & Lepper (2005) classified these formations as the undivided Dwyka Group (Table 2). The thickness distribution of the Dwyka Group is 37 extremely variable as a result of the uneven nature of pre-Karoo topography and the thickest intersection, 100m, was encountered in the Matabola borehole approximately 60km north-east of Lubimbi (Thompson, 1981). Thompson (1981) described the rocks of the Dwyka Group as largely consisting of coarse tillite and fine- to medium grained sandy material. The sandy material is indicative of outwash sands from retreating glaciers. From the outcrops noted in the Bari, Lubimbi and Gwaai River areas it was noted that coarse, pebbly deposits occur frequently in major river beds with rounded fragments up to 30cm in diameter. The glacial deposits were found to be fairly heterogeneous and described to be hard, pale grey to greyish yellow colour, unevenly tinged and containing red iron oxides (Thompson, 1981). In the Lubimbi area dull coal and bituminous shales, with intercalated siltstone and shale layers, were frequently intersected, indicating that during the Dwyka times conditions were already favourable for the accumulation of coaly material in localised embayments (Thompson, 1981). 3.2.2. Ecca Formations The Ecca Formations in the study area (Table 3) is defined as all sediments that directly overly the Dwyka Group up to the youngest carbonaceous mudstone or coal (Smith, 1984; Catuneanu, et al., 2005 and Palloks, 1984). 3.2.2.1. Lower Ecca Formations 3.2.2.1.1. Botswana According to Smith (1984) the broad pattern of the lower Ecca in Botswana is analogous with sedimentation in a widespread body of water opening to the sea. The sediments show that the basin was filled with prodeltaic sediments followed by increasingly arenaceous deposits indicating the presence of a fluviatile dominated delta system (Smith, 1984). 38 3.2.2.1.1.1. Tswane Formation Stansfield (1973) described the sediments directly overlying the Dukwi Formation as consisting of red and black shales with grey mudstones and refered to the unit as the Dukwe Mudstone. Although the naming of the unit seems to suggest association with the glacial sediments of the Dukwi Formation, Green (1966) grouped the beds with the Lower Ecca Group. Smith (1984) named the unit Tswane Formation, the currently accepted formation name, after a town by the same name approximately 20km southwest of the discovery borehole. There is no Tswane outcrop in the region and the lithological description by Green, (1966); Stansfield (1973) and Smith (1984) were based on drilling records from boreholes providing the most complete intersection of 7.5m. The base of this formation is characterised by grey mudstones grading into black, carbonaceous mudstones and a shaly coal with minor vitrinite bands. Towards the top of the unit the beds are black carbonaceous shales and red fissile shales. Smith (1984) postulated that the deposition initially occurred in open, aerobic conditions gradually becoming more euxinic and that the red colouration of the upper shales relates to the overlying unconformity with the Mea Arkose Formation as postulated by Stansfield (1973). During the ACB exploration programme the Tswane Formation was intersected in three boreholes (Y1-02, Y1-03 and PDM011, Figure 23) with the formation reaching a maximum thickness of 24.55m in Y1-03. The intersections noted in the three ACB boreholes showed a sequence of grey to black, carbonaceous mudstones and minor coal bands with some bright stringers in the middle of the unit (Anglo Coal Botswana, 2010). The argillaceous sediments of the Tswane formation were probably deposited conformably over the glaciolacustrine Dukwi Formation in broad lake systems which developed as a result of the final glacial retreat. This accumulation of the carbonaceous sediments soon after the glacial event suggests a cool to temperate environment (Smith, 1984). 39 3.2.2.1.1.2. Mea Arkose Formation The term Mea Arkose was first described by Stansfield (1973) from widely spaced “patchy” outcrops in the Shuane and Lepashe Rivers and at Mea Pan. Drilling records showed an even greater lateral extent of the formation. Green (1966) defined the formation as part of the Middle Ecca and describe samples as unique from any other formation in the area. Smith (1984) extrapolated the formation name Mea Arkose to the North East Botswana Basin and described it as the arenaceous unit directly overlying the Tswane Formation in turn overlain by the first carbonaceous unit. The base of the formation is described a coarse grained feldspathic sandstone directly overlying either the Tswane Formation or Pre-Karoo rocks. The top of the formation has been described as a cream-white fine to coarse-grained feldspathic sandstone. Grey-green shale partings have been noted towards the base (Smith, 1984). Historic drilling records show that the unit may also contain a number of thin shale beds with the thickest Mea Arkose intersection being 109.73m (Stansfield, 1973). ACB reported Mea Arkose intersections in six boreholes (Y1-01, Y1-02, Y1-03, Y1- 04, PDM009 and PDM011) with the thickest intersection of 52.44m being in Y1-03 (Anglo Coal Botswana, 2010). Stansfield (1973) postulated a fluviatile sediment transport direction from east to west based on local provenance and crossbedding. In the thicker sequences to the north a deltaic sandstone sequence with mudstone and coaly horizons may have developed. The Mea Arkose was recognised as an aquifer by Chilume (2002) in North East Botswana and from personal experience, posed difficulties with massive water intersections and losses during the ACB exploration drilling programme. It was not possible to analyse water samples but the water qualities varied greatly from highly saline to potable (Potgieter, 2015). 40 Figure 26 Location of the Smith (1984) and Anglo Coal Botswana (2010) boreholes in Botswana. 41 3.2.2.1.2. Zimbabwe In Zimbabwe, the basal succession, i.e. the Lower Wankie Sandstone, is invariably arenaceous with occasional fluvioglacial sediments and is the formation upon which the Wankie Main Seam rests (Figure 27). Thompson (1981) described the Lower Wankie Sandstone as a widely distributed fluvial deposit consisting of subangular to subrounded, coarse-grained, cross-bedded feldspathic sandstones, grits and pebble layers which outcrop along the edge of Kamitivi Inlier and gently dips eastwards with a maximum thickness of 45m. The rocks of the Lower Wankie Sandstones are commonly light coloured with some iron oxide staining giving rise to brown or reddish patches and the feldspar content is high enough in certain areas to term the lithological unit an arkose (Thompson, 1981). The deposition of this formation was most likely soon after the end of glaciation and poor sorting of the sediments in the region was noted by Thompson (1981) and Palloks (1984) suggests short transport distances of the material in a medium to high energy environment. 42 Figure 27 Stratigraphy of the lower Karoo Supergroup in the Mid-Zambezi Basin in Zimbabwe (after Thompson, 1981; Moyo, 2012 and Oesterlen & Lepper, 2005). 43 3.2.2.2. Upper Ecca Formations The Upper Ecca is defined as the unit that directly overlies the sediments containing the greatest amount of carbonaceous sediments and coal (Smith, 1984). This unit is believed to have been deposited in swampy, shallow water deltas over a widespread area in Botswana being the most favoured environment for the development of peat swamps and bogs (Smith, 1984). 3.2.2.2.1. Botswana 3.2.2.2.1.1. Northeastern Botswana The Tlapana Formation is arguably the most important Karoo Formation in north- eastern Botswana from an economic perspective because of potentially large scale coal deposits. Extensive coal exploration programmes were undertaken by Shell Coal and Anglo Botswana with drilling focussed around the Dukwe area and minor regional reconnaissance drilling and geophysical surveys between Nata and Pandamatenga. In 2007 ACB acquired 2 prospecting licences from Sekaname for CBM exploration and drilled 4 exploration boreholes with 7 additional holes being drilled on 19 further licences acquired in 2009. This data greatly aided in the further understanding of the Lower Karoo as outcrops of the sediments are very rare. The Tlapana Formation, mainly identified in the N series boreholes, was described as the mudstones, siltstones, carbonaceous mudstones and coals that overly the Mea Arkose Formation and which are overlain by the non-carbonaceous mudstones and siltstones of the Beaufort Group (Stansfield, 1973). Smith (1984) extrapolated the name Tlapana Formation to the North East Botswana Basin from the northern belt of the Central Kalahari basin. This formation was intersected in a number of the historic and ACB boreholes that contained coal seams thicker than 0.3 m with the maximum thickness intersected in N10/1 being 77.71m (Smith, 1984). The thickest intersection in the recent ACB boreholes was 66m in borehole Y1-01 (Anglo Coal Botswana, 2010). Smith (1984) used the drilling records from borehole N10/1 to describe the Tlapana Formation (Figure 26). The lower section of the formation is characterized as a 24m 44 thick succession hosting at least 26 bands of mixed bright and dull coal with carbonaceous and thin brown-grey mudstone interbeds. Of the 26 coal bands only 6 are thicker than 30cm. Siderite and pyrite nodules are common. A 1.2m thick hard, brown sideritic siltstone separates the middle and lower sections. The middle section is characterized as a succession of thin coal and coaly shales with siderite, intercalated with carbonaceous mudstones. The upper section consists of pale grey and dark grey shales with plant imprints capped by a 67cm coal seam and a further 38cm of carbonaceous mudstone. This upper unit is also regarded as the top of the Ecca Group (Smith 1984). Smith (1984) proposed that the coals of the Tlapana Formation were probably deposited in a gently subsiding swamp into which herbaceous material and debris drifted with interspersed mud flows during periods of fluctuating energy and flow rates. A distinct facies change was noted from borehole N10/1 toward the Precambrian basement high to the extent that in borehole N8/2 (Figure 26) the formation is thinner but a 6.42m coal zone, mainly consisting of dull coal with thin pyritic bands and carbonaceous mudstone partings, developed at the base of the formation (Smith, 1984). Above the coal in N8/2 the presence of intercalated sandstone sequence suggesting deposition in an impersistent channel that cannot be correlated in any other borehole supports this postulated facies change (Smith, 1984). This sandstone sequence was not reported in the ACB drilling records either. In a detailed sedimentological study for Anglo Coal Botswana, Bordy (2009) described the unit as intersected in four boreholes (Y1-01, Y1-02, Y1-03 and Y1-04) as being mudstone dominated with rare upward fining cycles suggesting deposition in a fluctuating energy environment (Figure 26). This was consistent with the findings by Smith (1984). During this study Bordy (2009) also re-evaluated the palaeo-flow directions throughout Botswana but was not able to improve on the findings by Smith (1984) in northeast Botswana (Figure 28). 45 Figure 28 Distribution map of the Late Carboniferous-Early Jurassic Karoo Supergroup in the Kalarhari Karoo Basin of Botswana showing the regional divisions of the basin, the borehole localities and palaeo-current directions in the coal-bearing Ecca Group (Bordy, 2009). 3.2.2.2.2. Zimbabwe 3.2.2.2.2.1. Wankie, Entuba and Western Areas Coalfields In the Wankie, Entuba and Western Areas coalfields the Wankie Black Shale and Coal formation grades from a thick basal coal seam, with coking coal, and mudstone succession to a carbonaceous mudstone unit with coal being replaced by pelitic or 46 clastic sediment around Entuba (Oesterlen & Lepper, 2005). In the Wankie Concession the formation typically consists of the Main Seam at the base, up to 14m thick, which is overlain by a carbonaceous mudstone succession, approximately 20m thick, and in some places intersected in the upper part by a thin coal seam and a 6m thick fireclay horizon. This pelite–coal lithology changes in the Western Areas Concession gradationally replacing the coal with clastic intercalations in the Main margin on one side representing the shore of the ancient Mid-Zambezi lake, and its down-dip lacustrine facies in the other direction (Oesterlen & Lepper, 2005). The Wankie Main Seam grades from a discrete coal seam to carbonaceous shale both laterally and vertically. The Upper Wankie sandstone overlies the main coal seam and these sandstones thin towards the centre of the palaeodepositional valley and into Zambia (Cairncross, 2001; Oesterlen & Lepper, 2005 and, Thompson, 1981). 3.2.2.2.2.2. Lubimbi Coalfield The lithology of the Lubimbi coalfields was found to be markedly different from that of the Wankie coalfields. The 40 to 50m thick succession consisting of bright and dull coal, carbonaceous mudstone, mudstone and a grey shale marker horizon, petrolgraphically similar to the fireclay at Wankie and usually containing six coal horizons (Oesterlen & Lepper, 2005). Palloks (1984) described the Black shale and coal Formation at Lubu as reaching a thickness of 50 to 70m, hosting the Main Coal Seam. This formation is overlain by carbonaceous mudstone containing a number of subordinate coal seams with some intercalated sandstone. 3.2.2.2.2.3. Sengwa Coalfield The Sengwa area has been divided into 2 further areas, Sengwa North and Sengwa South, by Palloks (1984) based on the geographic distribution north and south of the Sijarira Inlier. Oesterlen & Lepper (2005) also described the lithologies of the Wankie black shale and coal to be almost identical in the two areas. The base of the sequence is the Main Coal Seam overlain by the lower carbonaceous shale, the Upper Coal Seam and finally the upper carbonaceous shale. Both the lower and upper carbonaceous shales can be categorised as carbonaceous mudstones with thin barcoded coal laminae. Some of the differences between the areas are that the 47 fireclay is developed in the north but not in the south and that in some cases the Upper Coal Seam is poorly developed or even absent in the South (Palloks, 1984). 3.2.2.2.2.4. Gokwe Coalfield The coal bearing formation around Gokwe varies greatly from the aforementioned areas and is composed of various lithologies changing rapidly in a lateral direction (Oesterlen & Lepper 2005). Occasionally the Main Seam occurs at the base, with a maximum of 9 m thickness, overlain by siltstone and from other drilling records it appears that the sequence is represented only by carbonaceous mudstone, siltstone or sandstone and in cases it is completely missing. The package is thinner in comparison with an average thickness of only 15m. 3.2.2.2.2.5. Tjolotjo, Sawmills, and Insuza Areas Oesterlen & Lepper (2005) provided further information on the coal-bearing succession resulting from the three deep research boreholes drilled at Tjolotjo, Sawmills, and Insuza; all located in the Nyamandlovu district approximately 200km southeast of Wankie. Similar lithologies were encountered in the 3 holes and described by Oesterlen & Lepper (2005) as one or several thin coal seams are interbedded in an alternation of carbonaceous mudstone, with siltstone or sandstone. In general the sequence is upward coarsening with a decrease in organic material towards the contact with the overlying formations indicative of a deltaic deposition (Oesterlen & Lepper, 2005). It was found that the sequences closely resembled those of Gokwe indicating deposition on an alluvial plain as well. Figure 29 shows the depositional dynamics as postulated by Oesterlen & Lepper (2005) showing the locations of the interpreted alluvial plane, deltas and Mid-Zambezi Lake. 48 Figure 29 Postulated depositional environments of the coal bearing formations in the Mid-Zambezi Basin (Oesterlen & Lepper, 2005). 3.2.2.2.2.6. Upper Wankie Sandstone Formation Thompson (1981) described the Upper Wankie Sandstone Formation as coarse, cross-bedded deltaic sandstones, grits and pebble layers deposited on a relatively level surface. The Upper Wankie Sandstone and equivalent Waterfall Sandstone (Figure 27) is widely encountered across Zimbabwe and marks the end of a major accumulation of organic matter within the basin. The unit is predominantly arenaceous with only one argillaceous parting noted at Lubimbi. The thickest development described is at Gwaai where it forms a 70m escarpment (Thompson, 1981). 49 3.2.2.2.2.7. Tshale Formation Following the deposition of the Upper Wankie Sandstone, is the Tshale Formation a sequence of alternating sandstones and shales. Thompson (1981) postulated that the Tshale Formation is equivalent to the argillaceous parting noted in the Upper Wankie Sandstone at Hwange but is much thicker, with an average thickness of 37m and could host potentially economic coal deposits. The Tshale formation distribution parallels that of the Waterfall Sandstone on a regional scale and notable outcrops of black carbonaceous shale occur along the banks of the Tshale River. Tshale coals, in general, have higher ash contents than the lower coal measures (Thompson, 1981). 3.2.2.2.2.8. Ridge Sandstone Formation The Ridge Sandstone Formation (Figure 27) is regarded to be the continuation of the Waterfall Sandstone and is well exposed on the Dhalia-Lubimbi road (Thompson, 1981). Where the unit directly overlies the Waterfall Sandstone it is difficult to distinguish between the lithologies. The unit varies in thickness from 67m to 192m, averaging 30m, thinning east wards (Thompson, 1981). Overlying the Ridge Sandstone is a thick unit consisting of massive mudstone with minor siltstone and sandstone lenses known as the Madumabisa Mudstone, the uppermost unit of the Lower Karoo in Zimbabwe. There is no lithological break between the Madumabisa Mudstone and the carbonaceous mudstones of the Tshale Formation at Wankie (Mapani, et al., 2013). 50 3.2.3. The Post-Ecca Formations 3.2.3.1. Botswana The Post-Ecca Karoo deposits comprise formations ranging from late Permian to Cenozoic in age, distributed throughout the study area (Table 4) (Raath, et al., 1992) and (Oesterlen & Lepper, 2005). All groups, with the exception of the Stormberg Volcanic Group, are sediments. The Ntane Formation of the Lebung Group has been investigated widely, for its geohydrological wealth, in Botswana. Table 5 shows the stratigraphic units of the late Triassic and Jurassic formations of the Upper Karoo in Southern Africa compared to the Main Karoo Basin in South Africa (Catuneanu, et al., 2005). Approximate thicknesses are shown as the values in brackets, and ages are the italics. Table 4 The Post-Ecca Formations across the study area. 51 Table 5 Karoo stratigraphic units Upper Karoo in Southern Africa (Catuneanu, et al., 2005). 52 3.2.3.1.1. Tlhabala Formation The Beaufort Group in north east Botswana is represented by a single formation, the Tlhabala Formation (Smith, 1984 and Potgieter & Andersen, 2012). The formation continues from the Central Kalahari Basin over the Makgadikgadi basement high into the North East Botswana Basin (Smith, 1984). The base of the formation is regarded to be the contact with the carbonaceous mudstones and coal of the Tlapana Formation while the top is taken at the junction between the non- carbonaceous unit and the red beds of the Lebung Group. The 100m borehole intersection described by Stansfield (1973) showed deep weathering of the top of the formation and the true contact between the Tlhabala Formation and Lebung Group could not be established by Stansfield (1973) or Smith (1984). The unit mainly consists of brittle, grey, non-carbonaceous mudstones and siltstones and some minor limestone bands. The base of the formation was described as a 29cm thick non-carbonaceous mudstone with some carbonaceous fossil fragments directly overlying the youngest coal followed by a 3m bed of greenish mud-flake breccia. The 60m succession of mudstones that follow gradually becomes khaki yellow in colour and contains a number of limestone beds with interspersed calcite stringers up to 30cm thick Smith (1984). During his regional evaluation of the Karoo Supergroup, Smith (1984) had no data available of the Tlhabala Formation being intersected north of Nata but postulated that the formation could have been intersected in N12/1 had it been drilled deeper (Figure 26). ACB intersected this formation in six boreholes (Y1-01, Y1-02, Y1-03, Y1-04, PDM009 and PDM011) with the thickest intersection, 122m, achieved in Y1-03 (Figure 26). The ACB drilling strategy and basic borehole design was to drill percussion or mud rotary pre-collars to within the Tlhabala Formation and cored sections to below the Dukwi Formation (Anglo Coal Botswana, 2010). As a result of this the sections of the base of the Tlhabala Formation were described from drill chips and not core. The Tlhabala Formation was most likely deposited in a shallow, fairly quiet open water system into which very little arenaceous detrital material flowed and the basal fossil rich mudstones are indicative of a change from a peat swamp to an open widespread lake system (Smith, 1984). 53 3.2.3.1.2. Lebung Group The fluvial and aeolian deposits of the Lebung Group in Botswana has an affinity for the development for red beds and have previously been compared to the Stormberg Group (Molteno, Eliott and Clarens Formations) of South Africa by Green (1966) and Carney, et al. (1994). The ~150 m thick Group consists of red mudstones, sandstones and medium- and coarse-grained, orange to white sandstones which are either massive or cross-bedded and contain sand grains with frosted surfaces, indicating accumulation under aeolian conditions (Segwabe, 2008). The Lebung Group consists of a succession of red mudstones, siltstones and fine- to coarse- grained, red, orange and white, massive and cross-bedded sandstones. The group is underlain by a well-documented regional unconformity and is mostly conformably overlain by volcanic rocks of the Stormberg Lava Group over most of the Kalahari Karoo Basin (Bordy, et al., 2010b). In North East Botswana the group is represented by the Pandamtenga, Ngwasha and Ntane Sandstone Formations. The latter being the primary of potable aquifer in the region (UNESCO, 2004). Borehole P8 (Figure 26), although it did not intersect the base of the Pandamatenga Formation, was regarded as the most complete intersection and used to describe the lithology. The formation comprises medium-grained calcareous sandstones that become gritty parts or containing mud-flake breccias and conglomerates. Some intercalated purple-brown siltstones, silty mudstones and impure concretionary limestones were also identified (Smith, 1984). It is believed that the argillaceous beds were contorted by possible water-escape or quick-sand structures indicative of a rapid deposition in a relatively high energy aqueous environment (Smith, 1984). The lack of transportation of some of the mudstone fragments was interpreted to be suggestive of a bank-collapse fluviatile regime, however, the development of the concretionary limestones are indicative of a semi-arid terrestrial depositional environment (Smith, 1984). The sediments Ngwasha Formation was correlated with the red beds of the Karoo Supergroup by Green (1966), but Smith (1984) named the formation after Ngwasha Pan close to borehole P8 near the border with Zimbabwe. The base of this formation is characterized by a 4.86m thick red muddy siltstone with calcareous mudstone followed by a sequence of greyish cross-bedded and laminated sandstones and red-brown siltstones. The upper 24m consists of grey, 54 fine-grained sandstone and siltstone succeeded by grey sandstone with purple argillaceous stringers (Smith, 1984). The environment of deposition has been described as a semi-arid fluviatile environment and carbonate rich ground water evaporation, oxidising conditions giving rise to the red colouration (Smith, 1984). The Pandamtenga and Ngwasha Formations were not described separately by Anglo Coal Botswana (2010) and Bordy, et al. (2010)b and will be referred to as the Lower Lebung Group for the purposes of this study (Table 6). Table 6 Stratigraphic nomenclature of the Lebung Group used in this study with relation to Green (1966), Smith (1984), Anglo Coal Botswana (2010) and Bordy, et al., (2010)b. Group Formation Green (1966) Smith (1984) ACB (2010) Bordy (2010) This Study Cave Ntane Sandstone Formation Sandstone Stage Red Beds Ngwasha Mosolotsane Formation Lower Stage Formation Lebung Molteno Stage Pandamatenga Group Formation ACB obtained full intersections of the Lower Lebung Group in six boreholes (Y1-01, Y1-02, Y1-03, Y1-04, PDM009 and PDM011) with the thickest intersection, 148m, achieved in Y1-04 (Anglo Coal Botswana, 2010) (Figure 26). A regional distribution map produced by Bordy, et al. (2010)b shows the Lower Lebung possibly attains a thickness greater than 100m in the far north-eastern portion of Botswana (Figure 30). The ACB distribution data correlates with this thickness distribution but shows development further west. 55 Lebung Group Figure 30 Lower Lebung Group distribution throughout Botswana Bordy, et al. (2010)b. The Ntane Formation, the uppermost sedimentary unit of the Karoo Suppergroup, described by Stansfield (1973) in the Central Kalahari Basin was extrapolated to the North East Botswana basin because of the uniform aeolian sandstone deposits underlying the Stormberg Lava Group by Smith (1984). This formation is the primary source of potable groundwater throughout the majority of Botswana (Chilume, 2002), resulting in great number of borehole drilling records being available for regional mapping. This formation forms an extensive cover over the majority of the older Karoo formation overstepping basement highs and the base generally unconformably, in some cases condensed, overlies the older rocks (Smith, 1984). At 56 the base of the formation lies a thin greyish breccia containing polymict clasts suspected by Smith (1984) to lie above an unconformity marking a certain change from a silty to sandy facies as described in borehole P8. Similar breccia zones were noted throughout the sequence in some of the other boreholes described by Smith, (1984). As with the Lower Lebung ACB intersected the Ntane Formation in six boreholes (Y1-01, Y1-02, Y1-03, Y1-04, PDM009 and PDM011), with 88m being intersected in Y1-03 (Anglo Coal Botswana, 2010). The depositional environment is believed to be dry, aeolian with a predominant wind direction from east to west (Smith, 1984). 3.2.3.2. Zimbabwe 3.2.3.2.1. Madumabisa Mudstones In Zimbabwe, the basal formation of the upper Karoo is a thick unit consisting of massive mudstone with minor siltstone and sandstone lenses known as the Madumabisa Mudstone. There is no lithological break between the Madumabisa Mudstone and the carbonaceous mudstones of the Tshale Formation at Wankie (Mapani, et al., 2013). The Clay Ranch Formation described at Lubimbi is considered to be the equivalent of the lower section and the Hakano Beds the middle section of the Madumabisa Mudstones (Thompson 1981). At Lubimbi Thompson, (1981) found the Sidaga Mudstones of the Beaufort Group to be the equivalent to the lower Madumabisa Mudstones and the first true Triassic Formation. 3.2.3.2.2. Escarpment Grit In Zimbabwe, the Escarpment Grit was described as a fluvially deposited, coarse- grained massive bedded sandstone formation by Raath, et al. (1992). Titley (2013) described the Escarpment Grit to consist of coarse to very coarse-grained sandstone, locally conglomeratic, that fines upwards into more fine grained sandstones and intercalated mudstones. The unit has been subdivided into two informal members based on the facies. The lower member, called the braided facies is characterised by poorly sorted sandstones and pebbly sandstones with mudclasts, whereas the overlying meandering facies comprises of well sorted, upward fining 57 sandstones with mudclasts and pebble lag layers with laterally extensive mudstones (Titley, 2013). The Escarpment Grit sediments were observed at Sengwa by Palloks (1984). Best described as soft, earthy, red siltstones or very fine sandstones, the Triassic Fine Red Marly Sandstone Formation overly the Escarpment Grits and are poorly exposed and rarely described in borehole records. The clay minerals derived from weathered feldspar partly act as matrix cement and iron oxides introduced laterally give the sediment the distinct reddish colouring (Thompson, 1981). 3.2.3.2.3. Pebbly Arkose Formation Outcrops of the Pebbly Arkose Formation are more common than that of the Escarpment Grits and are believed to be a more transgressive unit. The arkose is coarse grained with randomly scattered quartz pebbles of varying sizes in irregular disturbed bands (Thompson, 1981). The formation is often a reddish brown due to the presence of iron oxides, however white to light yellow varieties of the arkose has been noted. The unit has been intersected in a number of boreholes with one intersection of 28.5m of Pebbly Arkose (Thompson, 1981). 3.2.3.2.4. Forest Sandstones The Forest Sandstones were the final sediments deposited in the Mid-Zambezi Basin prior to the eruption of the regional basalts of the Jurassic. Although outcrops are confined to small areas Thompson (1981) described the formation, from borehole logs and small scale mapping, as fine grained white to cream coloured quartzose aeolian sandstones with feldspar contents of up to 50%, iron oxide stained outcrops show a reddish colour. The general thickness of the formation is believed to be less than 30m. 3.2.3.3. Volcanic Rocks in the Study Area Green (1966) described the igneous unit directly overlying the youngest sediments of the Karoo Supergroup as equivocal to the Drakensberg Lavas found in South Africa. Stansfield (1973) named this unit of rocks the Stormberg Lava Group as encountered in the Central Kalahari sub-basin, a name that was extrapolated to the 58 remainder on Botswana, except in the Tuli Basin, where it is known as the Bobonong Lava Formation by Smith (1984). The succession generally consists of a number of amygdaloidal basalt flows up to 50m thick with the basal flows being finer grained and richer in amygdales, vesicles and thin tuffacious bands. The vesicles and amygdales often constitute zeolites, chlorite and calcite with partial quartz infill (Smith, 1984). ACB intersected the Stormberg Lavas in every hole drilled (Anglo Coal Botswana, 2010). The wide-spread non explosive nature of the basalts suggest the flows emanated as relatively quiet pulses from fissures and plugs from the northeast (Smith, 1984). The majority of the Karoo aged dolerite intrusions (Figure 31), visible as both dykes and sills, dated by Jourdan et al. (2004) were found to have been emplaced between 178.4 and 180.9Ma (Figure 32). It was also suggested that the dykes were emplaced at the same time as the basalt flows noted in north-west Zimbabwe as part of the greater Karoo Igneous Province (Jourdan, et al., 2004 and Jourdan, et al., 2005). Jones, et al. (2001) describes the Batoka Basalts, equivalent to the Stormberg Lava, as a succession of up to thirteen near horizontal flows ranging from 10m to 80m in thickness that form a flat plateau. The lack of sedimentary interbeds between the flows is suggestive of a very short eruption time for the entire formation (Jones, et al., 2001). The Botaka Basalts is chronologically and mineralogically identical to the Stormberg Lavas in Botswana and was deposited between 178Ma and 180Ma ago during the Jurassic (Jourdan, et al., 2005). 59 Figure 31 Location of the major Karoo igneous unit throughout Southern Africa (Jourdan, et al., 2004). Figure 32 Map of African Karoo flood basalts, sills, and related dyke swarms (Jourdan, et al., 2005). Notes: Dyke Swarms Mapped ODS: Okavango dyke swarm,ORDS: Olifants River dyke swarm (undated; intruding basement) (Jourdan, et al., 2004 and Jourdan, et al., 2005) SBDS: south Botswana dyke swarm (undated; intruding Karoo formations) SLDS: Sabi –Limpopo dyke swarm (mostly undated; intruding basement and Karoo formations) SleDS: south Lesotho dyke swarm (undated; intruding Karoo lava pile) SMDS: south Malawi dyke swarm (undated; intruding basement and Karoo group) RRDS: Rooi Rand dyke swarm (undated, intruding Karoo lava pile) NLDS: north Lebombo dyke swarm (undated, intruding Karoo lava pile) GDS: Gap dyke swarm (undated, intruding Karoo sediments). Notes on the Mapping of Data Botswana and western Zimbabwe are mostly covered by desert sand and that the Karoo volcanic rocks are therefore extrapolated from scarce outcrops, boreholes (Jourdan, et al., 2004 and Jourdan, et al., 2005) and aeromagnetic data 60 3.3. The Post-Karoo Sediments The Post-Karoo Sediments in the study area consist of the Late Cenozoic to Cretaceous Kalahari Group and some younger pan sediments, most notably those of the Makgadikgadi Pans in Botswana. The sediments of the Kalahari Group were deposited in a large basin stretching some 2200 km from South Africa in the south northwards through Botswana and Angola into the Democratic Republic of the Congo (Haddon & McCarthy, 2005). The thickness of these sediments can vary from less than 1m to 450m. The average thickness across the study area is approximately 100m thinning from west to east and being absent east of the Hwange Park in Zimbabwe (Figure 33). The accumulation of gravels continued as the down-warp of the basin progressed with interbedding of the gravel layers with sand and finer sediment carried by the rivers. Thick clay beds accumulated in the lakes that formed as a result of the back-tilting of rivers, with sandstone being deposited in braided streams interfingering with the clays (Haddon & McCarthy, 2005). A period of relative tectonic stability during the mid-Miocene saw the silcretisation and calcretisation of older Kalahari Group lithologies (Figure 34 & Table 7). This was followed in the late Miocene by relatively minor uplift of the eastern side of southern Africa and along certain epeirogenic axes in the interior. More significant uplift that followed in the Pliocene along epeirogenic axes may have elevated the Karoo Supergroup and basal Kalahari Group sedimentary rocks above the Kalahari basin floor where they were exposed to erosion (Haddon & McCarthy, 2005). The eroded sand was washed into the basin where it was reworked and redeposited by aeolian processes during drier periods, resulting in the extensive dune fields that are preserved today (Haddon & McCarthy, 2005). 61 Figure 33 Isopach and distribution of the Kalahari Group (Haddon & McCarthy, 2005). 62 Figure 34 Representative borehole logs from different locations across the Kalahari basin (Haddon & McCarthy, 2005). 63 Table 7 Attempted correlation of the Kalahari Group stratigraphy across the basin (Haddon & McCarthy, 2005). 64 Figure 35 Map of Botswana showing the location of the Makgadikagi Pans (SA-Venues). The best studied pans in the region are those of the Makgadikgadi Pan System (Figure 35) and the focus will remain on these for discussion. The pans can be regarded as an analogue for the smaller pans found towards the eastern boundary of Botswana (Potgieter, 2015). The Makgadikgadi Pans is a large hyper saline lake system in Central Botswana. The system is composed of a number of ephemeral pans with the largest ones being the Sua and Nwetwe Pans (Hogan, 2011). The paleo-lake that occupied the greater Makgadikgadi Basin was much larger than the present day extents. As shown on Figure 36 to Figure 38, the palaeo-lake covered a total area of 37 000km², stretching 65 from about 100km east of the present day Okavango Delta, to which it is joined by the Boteti River (Figure 38). The long axis of the basin is controlled by recent faults and it is bounded to the north and west by the Gidikwe Ridge (Himmelsbach, et al., 2008). The crest elevation of this feature is 940-945m above sea level, indicating unity of Ngami-Mababe-Makgadikgadi System at the time of its maximum extent. The entire system has been named Lake Paleo-Makgadikgadi and had a maximum areal extent in excess of 80 000km² which was larger than the present day Lake Victoria (Partridge & Maud, 2000). This Lake Paleo-Makgadikgadi probably formed during the Late Pleistocene times (~500ka ago) with the Zambezi, Okavango and Chobe Rivers entering the system. The lake reached a maximum level of 945m above sea level ~35ka ago after which the tectonically induced inclination of the system cut off the Zambezi River and this maximum water level would never be reached again (Himmelsbach, et al., 2008). Subsequent tectonism reduced the volume of water fed into the system by the Okavango and Chobe Rivers and drying out of the lake increased the salinity (Himmelsbach, et al., 2008). The development of the Makgadikgadi-Okavango-Zambezi (MOZ) basin was controlled by a series of mainly NE–SW trending faults that formed grabens in the underlying basement complex and the Karoo sequence. Tectonic activity along this trend resulted in uplift along the Zimbabwe-Kalahari axis and displacement along northeast–southwest trending faults (Himmelsbach, et al., 2008 and Kinabo, et al., 2007). This neotectonic activity resulted in the impoundment of the proto Okavango, Kwando, and upper Zambezi rivers and the development of the proto Makgadikgadi, Ngami and Mababe sub-basins (Kinabo, et al., 2007). Neotectonic activity related to the rifting in the Okavango Rift Zone (ORZ) has greatly influenced the geomorphology and drainage patterns of the MOZ basin resulting in the formation of the intra-continental Okavango alluvial fan (one of the world’s largest inland fan/deltas). Although the timing of initial rifting within the ORZ is not known, palaeoenvironmental reconstruction suggests that feeder rivers promoted extensive flow beyond the Thamalakane and Kunyere faults circa and beyond 120ka ago into the Makgadikgadi pans. However, between 120ka ago and ~40ka ago vertical movements along these rift-related faults caused the impoundment of the Okavango River and cutting off water supply to the pans. Thus it is possible that the 40ka ago 66 age represents a lower estimate of when active rifting was initiated within the ORZ (Kinabo, et al., 2007). The large pans Sua and Nwetwe are primarily composed of saline clays and efflorescence approximately 50 to 100 metres deep. Equilibrium between stabilised dunes and pans is driven by aeolian forces. Fluctuations in groundwater levels during interpluvials has led to hardpan formation of calcretes and silcretes resulting in low permeability. Annual rainfall accrues here averaging 500mm (Hogan, 2011). The highly saline water table is quite near the surface for such a semi-arid region, resulting from the fact that these pans are actually the termini of a large closed drainage basin (Hogan, 2011). 67 Figure 36 Lake Paleo-Makgadikgadi levels (Himmelsbach, et al., 2008). 68 Figure 37 Neotectonism of Lake Paleo-Makgadikgadi (Himmelsbach, et al., 2008). 69 Figure 38 Lake Palaeo-Makgadikgadi extents and bounding ridges (Partridge & Maud, 2000). 70 4. COAL DEVELOPMENT AND CHARACTERISTICS IN THE STUDY AREA Historically South Africa has enjoyed the greatest level of coal mining activity in Southern Africa, mainly due to better infrastructure and access to local and export markets. It has been estimated that Zimbabwe has in situ reserves of 11 billion tonnes of which 2.5 billion tonnes are believed to be shallow enough for opencast exploitation (Cairncross, 2001). In Zimbabwe the coal deposits are found in 2 main regions Save-Limpopo in the South and Mid-Zambezi in the north (Figure 39 and Table 8) (Cairncross, 2001). Abundant coal seams and interbedded carbonaceous mudstones are found in the upper Ecca Formations in Botswana, which could be a source rock for hydrocarbons (Hiller & Shoko, 1996; Cairncross, 2001 and Faiz, et al., 2013). Carney, et al. (1994) postulated that the thicker and better quality coal seams are found along the eastern margin of the Karoo basin. As a generalisation, the coal has high ash content and is of medium calorific value (Cairncross, 2001). The best coals located to-date are found in the Kgaswe coal field, near Palapye (Morupule Colliery) and, at the Mmamabula coal field in southern Botswana. In Botswana the furthest northern coal field is found at Dukwe (Cairncross, 2001 and Smith, 1984). In northeast Botswana the coal typically occurs in thin seams with mudstone and carbonaceous mudstone partings in the Tlapana Formation with minor stringers in the Tshwane Formation (Anglo Coal Botswana, 2010).Economic coal deposits are found throughout the Mid- Zambezi Basin in Zimbabwe with the best known deposits found at Wankie and Western Areas. The general quality of the coal in the Mid-Zambezi Basin is a high ash low rank bituminous coal with pockets of semi-anthracite. These pockets of higher rank coals have been attributed to localised thermal maturation by dolerite intrusions by Cairncross (2001). Key exploration reports, covering a range of coal fields and prospective regions, were used in this evaluation (Figure 40). The coordinates provided for the majority of the boreholes in Zimbabwe are on a local survey reference as used by the mine surveyors it was not possible to plot these in the map. For the evaluation the data was grouped per study area and evaluated as such. 71 Figure 39 Coal occurrences in Southern Africa with the basins of interest highlighted (Cairncross, 2001). See Table 8 for a brief description of the coal occurrences. 72 Table 8 Main characteristics of the coal occurrences shown in Figure 39 after, (Cairncross, 2001; Sparrow, 2012 and Barker, 2012) Occurrence Country Basin Occurrence Name Formation Age Number 1. South Africa Main Karoo Free State Vryheid Early Permian Artinskian 2. North Eastern Coalfield Vryheid Early Permian Artinskian 3. Kwazulu-Natal Coalfield Vryheid Early Permian Artinskian 4. Springbok Flats Springbok Flats Coalfield Warmbad Late Permian Kazanian Turfpan Early Permian Artinskian 5. Lephalale Ellisras Grootegeluk Late Permian Kazanian Vryheid Early Permian Artinskian 6. Limpopo Limpopo Coalfield Mikabeni Late Permian Kazanian Madzaringwe Early Permian Artinskian 7. Tshipise Pafuri Coalfield Mikabeni Late Permian Kazanian Madzaringwe Early Permian Artinskian 8. Swaziland Swaziland Swaziland Volksrust Late Permian Kazanian Vryheid Early Permian Artinskian 9. Botswana Kalahari Karoo Southwest No coal intersections 10. Kweneng Boritse Late Permian Kazanian 11. Mmamabula Mmamabula Early Permian Artinskian 12. Morupule Serowe Late Permian Kazanian Morupule Early Permian Artinskian 13. Northeast Tlapana Late Permian Kazanian 14. Northwest No coal intersections 15. Tuli Seswe Early Permian Artinskian 16. Namibia Karasburg Karasburg No coal intersections 17. Aranos Aranos Prince Albert Early Permian Artinskian 18. Waterberg Waterberg Teverede Early Permian Artinskian 19. Ovambo Ovambo Prince Albert Early Permian Artinskian 20. Huab Huab Verbrande Berg Early Permian Artinskian 21. Kaokoland / Damaraland Kaokoland / Damaraland No coal intersections 22. Angola Luanda Luanda No coal intersections 23. Zimbabwe Mazunga No coal intersections 24. Mid-Zambezi Mid-Zambezi Black Shale and Coal Early Permian Artinskian Wankie Main 25. Sabi-Lundi Sabi-Lundi Marare Late Permian Kazanian Malilongwe Early Permian Kungurian Lower Mkushuwe Early Permian Artinskian 26. Zambia Gwembe Gwembe Main Coal Seam Early Permian Artinskian (Mid-Zambezi) (Mid-Zambezi) 27. Luano Luano Gwembe Coal Early Permian Kungurian 28. Luangwa Luangwa Luwumbu Early Permian Artinskian 29. Barotse Barotse Luampa Early Permian Artinskian 30. Malawi Malawi Southern CoalfIeld Unnanmed Coal & Sandstone Late Permian Tatarian 31. Ngana Area Coal Measures Early Permian Artinskian 32. Livingstonia Area Unnanmed Coal & Sandstone Early Permian Artinskian 33. Mozambique Moatize/Tete Moatize/Tete Productive Series Early Permian Artinskian 34. Tanzania Ruhuru Ruhuru Upper Coal Measures Late Permian Ufimian Lower Coal Measures Early Permian Artinskian 35. Mhukuru Mhukuru Upper Coal Measures Late Permian Ufimian 36. Luwegu Luwegu No coal intersections 73 A FULL LIST OF THE DATA POINTS USED CAN BE FOUND IN Appendix A Figure 40 Investigation areas and regions used in this evaluation. 74 4.1. Coal Quality and Rank Coal is ranked based on the constituents, physical properties and thermal maturity changes as the raw peat is transformed to anthracite (World Coal Institute, 2005). The primary characteristics of the coal used for ranking are 1) the amount of carbon present in the sample, termed the Fixed Carbon Content, 2) the amount of moisture 3) the amount of non-combustible material referred to as the Ash Content, 4) the volatile matter content and 5) the heat value expressed as energy per weight. In the Mid-Zambezi Basin an apparent decrease in the coal rank over relatively short distance north-eastwards form Wankie to Sengwa and between Lusulu and Sengwa, has been noted (Cairncross, 2001). In Botswana, the Panadamatenga field has not been investigated extensively due to the inhibitive coal depths (Smith, 1984). One government borehole showed that the coal seams could be up to 700m deep as a result of thick Kalahari Group and Upper Karoo Supergroup development. Evaluations of the Dukwi field indicated that the coal is also of low rank (Cairncross, 2001). Two ACB boreholes, Y1-02 and Y1-03 intersected coal at a 705m, reinforcing these depth postulations (Anglo Coal Botswana, 2010). Proximate analyses are used to determine the fixed carbon, ash, moisture and volatile matter contents as percentages on air dried coal samples, the sum of the constituents must add up to 100%. The physical changes within the coal are caused by temperature and pressure resulting from the burial of the sediments containing the coal measures (Figure 41). As the coal is matured in high pressure, high temperature environments the ash, moisture and volatile matter components decrease (Figure 42) causing a relative increase in fixed carbon per weight and this increase causes an increase in the heating value (World Coal Institute, 2005). 75 Figure 41 Alteration of peat into coal (Kentucky Geological Survey, 2011). Figure 42 Coal types and uses (World Coal Institute, 2005). Thompson (1981) and Palloks, (1984) reported detailed proximate analytical data for a number of coal occurrences in the Mid-Zambezi Basin and; generalised quality information was obtained from a number of other sources. Anglo Coal Botswana, (2010) evaluated the coals intersected in four CBM exploration boreholes drilled in the Nata area, Cairncross (2001) reported key quality parameters for the Dukwe Field in Botswana. The variation in depth and rank across the study area is reflected in the level of exploration drilling activity in each of exploration areas. For the evaluation the ASTM standard on coal rank classification was used as it is relatable 76 to the maximum amount of gas that the coal can generate and store as determined by Eddy, et al., (1982). Krishan (1940) and Cardott (2012) demonstrated that the general ranking of coal can be determined based on the ash-free fixed carbon, and moisture contents (Figure 43 and Table 9). For these evaluations all analyses were corrected to ash-free values using the equations (Equation 1), as shown by Snyman (1998), were used. The coal qualities over the study area were derived from the available data and related to the Cardott (2012) & Krishan (1940) classification system (Table 10). C( C x 100 ash-free) = 100 - A V( = V x 100 ash-free) 100 - A M( M x 100 ash-free) = 100 - A Where: A = Ash content (%) C = Fixed carbon content (%) V = Volatile matter content (%) M = Moisture content (%) Equation 1 Ash-free content estimation formulae (Snyman, 1998). Table 9 Coal classification properties on ash free basis (constructed after Krishan, 1940 and Cardott, 2012). Coal Rank Coal Constituents (Ash-Free Basis) Fixed Volatile Bed Carbon Matter Moisture Lignite 32 38 30 Subbituminous - C 37 36 27 Subbituminous - B 43 35 22 Subbituminous - A 45 38 17 High Volatile Bituminous - C 45 40 15 High Volatile Bituminous - B 53 40 7 High Volatile Bituminous - A 62 32 6 Medium Volatile Bituminous 69 25 6 Low Volatile Bituminous 77 17 6 Semi Anthracite 85 12 3 Anthracite 92 5 3 77 INCREASING RANK Figure 43 Graphical differentiation of coal constituent distributions, based on proximate analysis (constructed after Krishan, 1940; Middelkoop, 2009 and Cardott, 2012). 78 Table 10 Coal ranks across the study area derived from ash-free proximate analyses. Country Area Source(s) Minimum Maximum Average General Coal Rank Comments Zimbabwe Western Areas Palloks (1984) 63 1 23 61 3 37 75 2 30 69 High Volatile Bituminous A to Summarised borehole logs and analyses. Medium Volatile Bituminous Entuba 125 0 15 71 8 28 84 1 23 75 Medium Volatile Bituminous Summarised borehole logs and analyses. Lubu 28 1 27 55 4 42 71 2 35 63 High Volatile Bituminous B to Summarised borehole logs and analyses. High Volatile Bituminous A Sengwa South 10 3 25 62 6 33 70 5 28 67 High Volatile Bituminous A Summarised borehole logs and analyses. Sengwa North 11 3 26 64 6 33 69 5 29 66 High Volatile Bituminous A Summarised borehole logs and analyses. Lusulu Palloks (1984); 3 14 30 51 16 34 56 15 32 53 High Volatile Bituminous C to Summarised borehole logs and analyses. Mapani, et al. (2013); High Volatile Bituminous B Padcoal (Pvt) Ltd (2011) Wankie Palloks (1984) 2 1 26 73 1 26 73 1 26 73 High Volatile Bituminous C to Only averages for the Wankie seams given Medium Volatile Bituminous by Mapani et al. (2013). High ash bright thin bands with interbedded mudstone reported, some Fischer oil reported by Padcoal (Pvt) Ltd (2011). Gokwe Oesterlen & Lepper 1 5 29 65 5 29 65 5 29 65 High Volatile Bituminous C to Reported by Padcoal (Pvt) Ltd (2011) as (2005); Padcoal (Pvt) Medium Volatile Bituminous part of an investment brochure. Ash values Ltd (2011) reported as between 20 & 30 % by Oesterlen & Lepper (2005). Lubimbi Oesterlen & Lepper 1 * High ash bright thin bands with interbedded High Volatile Bituminous C Described in the text only. (2005) mudstone reported Busi 1 * High ash lower quality coal reported Subbituminous No quality data is available. Tjolotjo, Sawmills, 1 * High ash lower quality coal reported Subbituminous Described in the text only. and Insuza Botswana Northeast Botswana Smith (1984), Anglo 39 ** Smith (1984) and Cairncross (2001) reported high Subbituminous Proximate data not published. Personal Coal Botswana, ash low quality coal around Dukwe, Anglo Coal experience on the project. (2010) Potgieter Botswana (2010) only intersected the coal in 4 (2015) boreholes and reported generally poor quality. * Quality estimated from literature described as very high ash and lower quality. Low quality subbituminous coal assumed. ** Personal experience. Very high ash and very low carbon contents. Subbituminous coal encountered. 79 Number of Data Points Evaluated Moisture Content (%) Volatile Matter (%) Fixed Carbon (%) Moisture Content (%) Volatile Matter (%) Fixed Carbon (%) Moisture Content (%) Volatile Matter (%) Fixed Carbon (%) 4.2. Coal Thickness, Depth and Regional Continuity The total coal thickness was evaluated across the study area as this is a pivotal component to the resource assessment. For the purposes of this study the full coal measures were assessed. Once an evaluation of the production capacity is attempted, in a localised field, it is of utmost importance to isolate the discreet primary production seams and establish the continuity or possible compartmentalisation of these seams. However, with the sparse data this is not possible nor is it required at the regional scale of the assessment and the composited coal thickness in a borehole can be used. Composite coal thicknesses for each of the boreholes were calculated and used for this study. The composite was limited to the Ecca Group coals. In Botswana only four of the Anglo Coal Botswana exploration boreholes intersected coal. These were all placed in the Nata Sub-Basin as identified by Smith (1984). The thickest intersections were towards the west where 12m coal was intersected in boreholes Y1-01 and Y1-03 (Figure 26) at a depth of approximately 500m below surface (Anglo Coal Botswana, 2010). In the Mid-Zambezi basin the main focus area for coal extraction is in the Wankie Coalfield, a collective name for the coal deposits at the Wankie Concession, Entuba, Western Area, Lubu, Sengwa, Lusulu, Sinamatella and Lukosi, and the Lusulu Coalfield (Oesterlen & Lepper, 2005). In the Wankie Concession the Main Seam (k2-3) varies in depth from 60 to 70m (Figure 44) below ground level (Oesterlen & Lepper, 2005) and in thickness from 2m – 12m with the lower portion having excellent coking properties (Figure 45) with low ash (<10%) values. Some measurements of high sulphur were noted by Cairncross (2001). 80 Figure 44 The Wankie Main Seam (k2-3) lithofacies changes at the Wankie Concession (Oesterlen & Figure 45 A typical vertical section through the Wankie Main Seam, Zimbabwe (Cairncross, 2001). Lepper, 2005). 81 Table 11 shows the maximum, minimum and average measured coal thicknesses and top depths from borehole records and published literature for each of the investigated areas. The Botswana measurements were compiled from wireline and geological logs (Anglo Coal Botswana, 2010) and in Zimbabwe the data was taken from historic reports by Palloks (1984) and Thompson (1981). For the resource evaluation all thickness measurement data was combined and statistically analysed. Table 11 Minimum, maximum and average coal thicknesses and top depths from borehole records. Country Area Source(s) Depth (metres Composite below ground Thickness level) (metres) Zimbabwe Western Areas Palloks (1984) 63 4 336 162 2 14 7 Entuba 125 6 560 118 3 20 11 Lubu 28 11 112 48 2 18 8 Sengwa South 10 6 161 82 9 17 12 Sengwa North 11 0 145 75 8 15 12 Lusulu Palloks (1984); 3 98 197 92 4 9 6 Mapani, et al. (2013); Padcoal (Pvt) Ltd (2011) Wankie Palloks (1984) 2 100 700 265 8 12 10 Gokwe Oesterlen & 1 200 300 250 0 9 5 Lepper (2005); Padcoal (Pvt) Ltd (2011) Lubimbi Oesterlen & 1 12 190 101 2 47 25 Busi Lepper (2005) 1 60 80 70 10 20 15 Tjolotjo, 1 270 330 300 0 9 5 Sawmills, and Insuza Botswana Northeast Smith (1984), 39 5 793 96 1 24 10 Botswana Anglo Coal Botswana, (2010) Potgieter (2015) 82 Number of Data Points Evaluated Minimum Maximum Average Minimum Maximum Average 5. ASSESSMENT OF THE CBM RESOURCE OF THE STUDY AREA Production of CBM in Zimbabwe, has been proven in a number of key wells by Shangani Energy, falling within the study area, indicated in Figure 46 (Maponga, 2014). No production has been proven in north-eastern Botswana to date. For the study Schlumberger GeoX software was used to determine the gas in place (GIP) volumes. The determination of the GIP was achieved by a Monte Carlo simulation of the Aminian (2005) CBM resource equation. GIP = A x h x RHOB(c) x G(c) Where: A = Area (km2) h = Coal thickness (m) RHOB(c) = Coal density (g/cm 3) G(c) = Gas content (scf/tonne) Equation 2 Calculation of gas in place volumes (Aminian, 2005). LUPANE I SG 1731 – Shangani Energy – C-5 Well Figure 46 Shangani Energy exploration and production grants in Zimbabwe showing the test location from which CBM was produced (Maponga, 2014). Not all the inputs required for the resource evaluation were directly measured and reported in the drilling record as some data was not applicable to coal exploration. 83 The coal thickness measurements (h) were taken from regional drilling records and reports. The extent of the Karoo Supergroup from GIS data was used to determine aerial component (A) of the resource evaluation. Due to a lack of widely measured Coal Density (RHOB(c)) and Gas Content (G(c)) data these values had to be inferred using the existing data compared to some sparse measurements taken by mainly Anglo Coal Botswana (2010) in north-eastern Botswana and Kubu Energy (2014) from a coal field in central Botswana. The Kubu Energy (2014) data, comprising nine CBM exploration wells (Figure 47), is one of the most comprehensive collected in the region (Potgieter, 2015). This dataset includes comprehensive geological, gas desorption, proximate, adsorption isotherm and petrological information from all nine boreholes drilled (Kubu Energy, 2014). The Kubu Energy exploration boreholes marginally fall outside the study area within the Northern Belt Central Kalahari sub-basin. Smith (1984) determined that the lithostratigraphic divisions of the Northern Belt Central Kalahari and North East Botswana sub-basins are the same (Figure 19). The Kubu Energy boreholes were not included in the assessment but were used as an analogue for the determination of the poorly measured data that is required for the CBM resource assessment. Without key production capacity parameters such as permeability tests, detailed isotherm measurements and gas contents it is impossible to estimate a recovery factor for a basin of this size. Reviewing other regional studies where this information was available, in some form, a great deal of variation was noted (Table 12). Recovery factors can also be influenced by adjusting the production well spacing, drilling method, type of reservoir stimulation and biogenic or carbon dioxide enhancement methods (Boyer, et al., 2007; Swindell, 2007; Litynski, et al., 2014 and Fallgren, et al., 2013). Table 12 CBM recovery factors for three North American plays. Area Recovery Factor Source (%) Horseshoe Canyon 26 - 39 Jenkins (2008) Mannville 21 - 38 Jenkins (2008) United States (Lower 48 States) - Generalised 14 Nuccio (2000) 84 Figure 47 Location of the study area showing investigation areas in Zimbabwe, exploration boreholes in north-eastern Botswana and the Kubu Energy boreholes. 85 5.1. Area For the Area (A) component of the investigation the mapped Karoo Supergroup from GIS datasets by (Pitfield, 1996), (Mothibi, 1999) and (Persits, et al., 2011) was extracted for only the study area (Figure 48). Even though the study area has a surface extent of 167 057km² the area occupied by Karoo Supergroup rocks is only 134 666km². Figure 48 Extent of the mapped Karoo Supergroup in the study area (after Pitfield, 1996; Mothibi, 1999 and Persits, et al., 2011). 5.2. Coal Thickness A total of 250 coal thickness (h) measurements available in the reports by Anglo Coal Botswana (2010), Oesterlen & Lepper (2005) Palloks (1984) and Thompson (1981) and Smith, (1984) were statistically analysed (Table 13) to compile a histogram (Figure 49) of the total coal thicknesses. The distribution of the data is lognormal with thicknesses ranging from 1m to 23.65m. 86 Table 13 Summarised statistics of all total coal thickness values across the study area. Summary Statistics of Total Coal Thickness Data (m) Mean 9.58 Median 9.66 Mode 11.66 Standard Deviation 3.67 Range 22.65 Minimum 1.00 Maximum 23.65 Count 250 Figure 49 Distribution of total coal thickness data. 5.3. Coal Density The coal density (RHOB(c)) values of the coal are used to calculate the bulk weight of the coal along with the thickness (h) and area (A) data. The density can be determined from laboratory analyses and using wireline geophysics. The wireline tools can also be used to identify clean coal in the borehole. 87 The primary tool used by Anglo Coal Botswana (2010); and Kubu Energy, (2014) for coal identification from exploration boreholes is the formation density logging tool. The tool is sidewall tracking (Figure 50a) with a single arm calliper, measuring the geometry of the borehole. The calliper and density (RHOB(c)) data is processed together to remove any false density readings based on sidewall rigousity. The resultant log is referred to as the compensated density log. Anglo Coal Botswana, (2010) used a bulk density cut-off of 1.8g/cm³ and Kubu Energy (2014) a cut-off of 1.75g/cm³, where all densities lower than the cut-off density are regarded as coal intervals (Figure 50b). a) Formation Density Logging Tool (Crain, b) Compensated density log showing 2015) interpreted coal horizons (Kubu Energy, 2014) Figure 50 Formation density logging tool and compensated density log indicating coal seams. Computer Support Group (2011) reported the laboratory determined density of solid bituminous coal to be 1346kg/m³ (1.346g/cm³) and solid anthracite as 1506kg/m³ (1.506g/cm³). An analysis of the wireline logs from the Kubu Energy drilling campaign in Botswana showed that all measurements less than 1.75g/cm³ measurements were distributed between 1.1g/cm³ and 1.75g/cm³ (Kubu Energy, 2014), the statistically determined mode was 1.70g/cm³ (Table 14 and Figure 51). 88 Table 14 Summarised statistics of density values less than 1.75g/cm³ obtained from the Kubu Energy (2014) wireline logs. Summary Statistics of Wireline Density Data less than 1.75g/cm³ (g/cm³) Mean 1.53 Median 1.55 Mode 1.70 Standard Deviation 0.14 Range 0.64 Minimum 1.11 Maximum 1.75 Count 13427 Figure 51 Distribution of densities from the compensated density logs of all values less than 1.75g/cm³ collected from 9 coal exploration boreholes in Botswana (after Kubu Energy, 2014). 89 5.4. Gas Content The measurement and determination of the gas content (G(c)) forms an integral part of the resource evaluation. As very little CBM exploration has taken place in the study area it is necessary to infer the potential gas content values of the coal from the coal quality data. This was achieved by evaluating the coal quality measurements and calculating a possible gas content for the coal seams using the graphs published by Eddy, et al. (1982) using the measured depths of the coal seams. Saturation evaluations require accurate gas content measurements combined with the adsorption isotherm measurements, however, previous investigations in the region have not been consistent in the quality control of measurements and there is a lack of reliable adsorption isotherm data in the public domain (Potgieter, 2015). For the evaluation a range of saturations will be used based on the evaluations by Kubu Energy (Faiz, et al., 2013) and Shangani Energy (Barker, 2006). A number of sources were used to obtain the depth and thickness of the coal measures. ACB drilled 12 CBM exploration boreholes in north-eastern Botswana (Anglo Coal Botswana, 2010); Thompson (1981), Palloks (1984) and Oesterlen & Lepper (2005) evaluated a series of datasets from the main coal fields in Zimbabwe. Shangani Energy drilled a number of CBM exploration boreholes in Zimbabwe, these borehole results were illustrated by (Barker, 2006) at the Botswana resources sector conference. Figure 52 and Table 15 show the locations and types of data available for this evaluation. There is a lack of regionally available gas composition data in the public domain with the only freely available dataset being from central Botswana (Kubu Energy, 2014). The incorporation of gas content values in this evaluation was impossible and with the aim of evaluating the total resource in place did not add any material value. In more localised evaluations where gas composition data is available it is essential to fully understand the impact of composition on commerciality. 90 Table 15 Data sources and types used throughout this evaluation. Source Area Data Types Anglo Coal Northeastern Botswana Borehole data, gas content measurements Botswana (2010) and report on exploration findings Smith (1984) Northeastern Botswana Borehole data, report on regional coal information Thompson Lubimbi Report on coal occurrences and quality (1981) Dahlia & Hankano Palloks (1984) Report on coal occurrences and quality Entuba Lubu Lusulu Sengwa Western Areas Wankie Oesterlen & Reporting of coal intersections and general Lepper (2005) Bari coal quality data Busi Insuza Kaonga Lubimbi Lubu Lusulu Sawmills Sebungu Sengwa North Senwa South Sessami Tsholotsho Wankie Barker (2006) – Conference Presentation: Maps and graphs of Shangani Entuba depths and gas content information Energy Gwaai Lupane Sengwa Wankie 91 Zimbabwe Figure 52 Investigation areas in Zimbabwe and boreholes in Botswana used in this evaluation (after Thompson, 1981; Palloks, 1984; Smith, 1984; Oesterlen & Lepper, 2005; Barker, 2006 and Anglo Coal Botswana, 2010). 92 5.4.1. Hydrocarbon Generation Potential of Coal Hydrocarbon generation within carbonaceous material is controlled by three components, 1) carbon content, 2) kerogen type and 3) thermal maturity. The carbon content and kerogen type are mainly controlled by the depositional system and provenance of sediments in a basin and the thermal maturity is controlled by the maximum pressures and temperatures to which the kerogen and organic carbon has been subjected to. Coal contains predominantly Type III and IV kerogens (Table 16) and the resulting hydrocarbons are predominantly gas, however, it is possible that some oils may be generated (SPE UGM SC, 2014). Evidence of oil in the coal seams has been noted at Wankie by Palloks (1984) and Thompson (1981) with up to 2.5% oil content in some samples. Thompson (1981) regarded the oil as a Fischer- Tropsch oil and the regional distribution is not understood fully, thus it will not be evaluated as part of this study. Table 16 Kerogen types as determined by visual kerogen analysis, origin, and hydrocarbon potential (SPE UGM SC, 2014). Thermal maturity is mainly measured by 1) the reflectance of vitrinite (RoV or RV) during petrological examination and 2) maximum kerogen temperature (Tmax) calculated during Rock-Eval measurements (Figure 53). The maturity is controlled by pressure and temperature which in turn is controlled by the depth of burial. 93 Different types of hydrocarbons are generated within specific maturity ranges (Figure 54) (McCarthy, et al., 2011). Figure 53 Correlation of maturity and coal type (Corrado, et al., 2010). Figure 54 The temperature transformation of kerogen with increased depth and temperature (McCarthy, et al., 2011). 94 As the coal is subjected to greater pressures and temperatures the vitrinite, derived from cell wall wood material, undergoes different stages of maturation resulting in an increase of the reflectance of vitrinite. Vitrinite Reflectance (RoV) is a measurement of the percentage of light reflected off the vitrinite maceral at 500X magnification in oil immersion (Cardott, 2012). As part of the Western Canada Sedimentary Basin (WCSB) Atlas Smith, et al. (1994) produced a table outlining the expected (RoV) ranges for the volatile matter, moisture and heating value for specific coal ranks (Figure 55). Figure 55 Coal rank classification based on maturity, moisture content, volatile matter content and heating value (Smith, et al., 1994). The generation of hydrocarbons in source rocks are primarily controlled by the process where kerogens are transformed into “dead carbon”, this process is known as cracking and is controlled by depth and pressure increases. The three primary stages of the maturation process are 1) diagenesis, 2) catagenesis and 3) metagenesis which are controlled by thermal and pressure increases, mainly due to an increase in the burial depth as a result of increased sediment load and basin subsidence. During the early stages of diagenesis biologically controlled gas is 95 mainly formed (McCarthy, et al., 2011). The generation of biogenic methane has been noted as the dominant gas source in the Central Kalahari Basin in Botswana by Faiz (2014). As part of the Kubu Energy drilling campaign a comprehensive sampling and analysis programme was followed (Faiz, et al., 2013). During this programme a far more expanded isotope sampling project of the desorbed methane was conducted compared to the previous ACB campaigns in Botswana (Anglo Coal Botswana, 2010; Faiz, et al., 2014 and Potgieter, 2015). The dominance of biogenic gas has a noted adverse effect on the saturation levels of the coals and subsequently the gas production capacity (Zheng, et al., 2011). A lack of widespread sample data across the region remains one of the shortcomings in the available database for CBM evaluation (Potgieter, 2015). Figure 56 Relative gas production amounts from coal in selected Australian basins (Faiz, et al., 2012). 96 During catagenesis, resulting from further burial, oil and gas is generated with rich and dry simple gasses being formed at even greater burial depths during metagenesis (McCarthy, et al., 2011). Faiz (2012) showed that the Permian coals of Australia have the ability to generate thermogenic gas across a wide range of thermal maturities. The Bowen Basin in eastern Australia has the potential to produce methane and higher hydrocarbons in a range from 0.6% Vitrinite Reflectance (VR) to greater than 2% VR with peak production around 1.2%VR (Figure 56). 5.4.2. Estimation of the Gas Content of the Coal in the Study Area As part of the Central Kalahari Exploration Campaign in Botswana Kubu Energy sampled the coal intersections extensively and collected a total of 41 isotherm samples (Kubu Energy, 2014). The coals were extensively intruded by dolerite sills that had a noted effect on the coal quality and gas content measurements (Kubu Energy, 2014; Faiz, et al., 2013; Faiz, et al., 2014 and Potgieter, 2015). However, it remains difficult to determine the true effect of intrusives on the apparent rank and maturity of the coal. Faiz (2014) found that in Central Botswana the dolerite intrusion had the potential to increase specific samples from the 0.5%VR average to >4%VR and in a study of coals from the Gunnedah Basin, Australia Gurba & Weber (2001) determined that the intrusions were capable of increasing the rank from the average 0.67%VR to 6%VR. Faiz (2014) demonstrated the effects of the intrusions are localised a generalised rank of the coal across the region was used to determine the potential gas holding capacity. 97 Figure 57 Simplified elevation cross-section across the Kubu area showing the encountered coal seams and dolerite intrusions (Faiz, et al., 2013). 98 The isotherm samples collected and analysed by Kubu made it possible to calculate the maximum gas holding capacity for each of the coal zones intersected. The dataset was reviewed and boreholes were selected to be evaluated with respect to the gas generation and storage capacity, see Appendix D for the full dataset. For this selection of the data to be analysed additional criteria were used and only samples that comply with the thresholds were evaluated further (Table 17). Of the original 41 samples ten were extracted for further isotherm data evaluation (Table 18). Table 17 Selection parameters and thresholds. Parameter Threshold Threshold Description 1 Dolerite Intrusives Proximity of The effect of the intrusives is difficult sample may not to fully quantify however, Faiz (2014) be less than 30m demonstrated that the effects in from a dolerite borehole 134C7 the coal rank was intrusive significantly increased with respect to the surrounding samples. The average thickness of the intrusives encountered is 29.9m. A minimum proximity of 30m was selected to compensate for 1:1 thermal effect range around intrusives. 2 Measured Gas Measured gas Gas content lower than 20scf/T are Content content values regarded as low and was regarded must be greater as contributing factors to the sub than 20scf/T economic status of the project (Kubu Energy, 2014 and Potgieter, 2015). 99 Table 18 Subset of samples used in the gas content evaluations. Borehole Depth From Depth To Sample Sample Zone Sampling Intrusives Mid-Point Number Isotherm Analyses (m) (m) (m) 12 134C7 462.86 463.14 463.00 CH-7-021 Z2 ✔ ✔ ✔ ✔ 14 134C6 319.59 320.19 319.89 CH-6-002 Z3 ✔ ✔ ✔ ✔ 15 134C6 328.84 329.40 329.12 CH-6-008 Z3 ✔ ✔ ✔ ✔ 16 134C6 340.05 340.64 340.35 CH-6-013 Z2 ✔ ✔ ✔ ✔ 25 135C4 450.82 451.40 451.11 CH-04-D7 Z2 ✔ ✔ ✔ ✔ ✔ 28 136C3 364.70 365.00 364.85 CH-03-005 Z3 ✔ ✔ ✔ ✔ 38 136C1 268.38 268.98 268.68 CH-01 D004 Z3 ✔ ✔ ✔ ✔ 39 136C1 275.24 275.44 275.34 CH-01 D005 Z3 ✔ ✔ ✔ ✔ 40 136C1 277.30 277.90 277.60 CH-01 D006 Z3 ✔ ✔ ✔ ✔ ✔ 41 136C1 279.96 280.17 280.07 CH-01 D008 Z3 ✔ ✔ ✔ ✔ ✔ ✔ 100 Sample Sequence Gas Desorption Methane Nitrogen Carbon Dioxide Proximate Analysis Vitrinite Reflectance Proximity to Intrusive <30m Vertical Thickest Intrusive Thickness (m) The isotherm analyses provide information that can be used to determine the maximum sorptive capability of a sample at a specific reservoir pressure. This pressure is related to the depth of a coal seam if the pressure gradient is known. The coal seams evaluated for the Kubu Energydrilling campaign generally were not over-pressured and a hydrostatic pressure gradient of 0.433psi/ft was used in the evaluations (Kubu Energy, 2014 and Potgieter, 2015). The key parameters (Figure 58) that were derived during the isotherm analysis were the Langmuir Volume (VL), the maximum volume of gas that can be adsorbed by coal at infinite pressure, and Langmuir Pressure (PL) also known as the critical desorption pressure (CDP), the pressure at which one half of the Langmuir volume can be adsorbed by the coal (IHS Inc., 2014). Langmuir Isotherm Parameters a) Langmuir Volume (VL) b) Langmuir Pressure (PL) Figure 58 Langmuir isotherm parameters (IHS Inc., 2014). IHS Inc. (2014) provided an equation to determine the maximum gas holding capacity for specific pressures (Equation 3). This equation assumes that the entire sample analysed contributes to the gas generation and storage capacity. The ash, volatile matter and moisture contents in the coal are inert in the generation and storage capacity. As a result of this IHS Inc. (2014) showed an equation for calculating the dry, ash-free (DAF) gas contents (Equation 4). The DAF gas content calculation can be simplified, in a similar way as calculating DAF volatiles or fixed carbon equation by Snyman (1998), as used in this evaluation (Equation 5). 101 VL ρ G(c) = PL +ρ Where: G(c) = Gas content (scf/T) VL = Langmuir Volume (scf/T) PL = Langmuir Pressure (psi) ρ = Sample Pressure Equation 3 Determination of gas content from a Langmuir isotherm (IHS Inc., 2014). DAF VL ρ G(c) = (1- Ca – Cw) PL +ρ Where: DAFG(c) = Dry, Ash-Free Gas Content (scf/T) Ca = Ash Content (decimal fraction) Cw = Moisture Content (decimal fraction) VL = Langmuir Volume (scf/T) PL = Langmuir Pressure (psi) ρ = Sample Pressure Equation 4 Determination of dry, ash-free gas content from a Langmuir isotherm (IHS Inc., 2014). DAF G(c) G(c) = (100%- Ca – Cw) Where: DAFG(c) = Dry, Ash-Free Gas Content (scf/T) G(c) = Raw Gas content (scf/T) Ca = Ash Content (%) Cw = Moisture Content (%) Equation 5 Determination of dry, ash-free gas content (after Snyman, 1998). The subset of ten samples was evaluated and the maximum gas holding capacities, both raw and DAF were calculated (Table 19). The maximum DAF gas holding capacities ranged from 67scf/T to 239scf/T whereas, the DAF measured gas contents 118scf/T to 319scf/T. 102 Table 19 Data evaluation of the select Kubu samples (after Kubu Energy, 2014). Sample Analyses Data Interpretation Measured Proximate Analysis Isotherm Analysis Isotherm Data Interpretation Gas Content Air Dried Ash-Free % VR (m) scf/T scf/T % % % % % % % psia scf/T scf/T psi/ft ft psi scf/T scf/T (mean) 12 134C7 463.00 CH-7-021 26.78 32.12 3.72 12.91 32.05 51.33 4.27 36.80 58.94 0.55 749 224 364 0.43 1519.01 672.43 105.97 172.20 14 134C6 319.89 CH-6-002 21.78 42.05 5.99 42.21 23.38 28.41 10.37 40.46 49.17 0.47 1073 223 454 0.43 1049.50 469.13 67.84 138.11 15 134C6 329.12 CH-6-008 37.11 47.18 5.27 16.07 34.62 44.04 6.28 41.25 52.47 0.51 707 307 404 0.43 1079.78 482.24 124.49 163.82 16 134C6 340.35 CH-6-013 39.94 49.05 4.98 13.60 32.00 49.41 5.77 37.04 57.19 0.60 700 308 408 0.43 1116.60 498.19 128.06 169.64 25 135C4 451.11 CH-04-D7 56.73 67.23 2.31 13.30 28.53 55.86 2.66 32.91 64.43 0.84 580 450 601 0.43 1480.00 655.54 238.76 318.87 28 136C3 364.85 CH-03-005 37.55 50.12 2.10 22.98 29.07 45.84 2.73 37.75 59.52 0.83 709 371 534 0.43 1197.00 533.00 159.21 229.16 CH-01 38 136C1 268.68 33.23 44.71 5.45 20.23 31.50 42.82 6.84 39.49 53.68 0.47 867 262 378 0.43 881.49 396.38 82.20 118.60 D004 CH-01 39 136C1 275.34 33.13 45.05 5.43 21.04 30.70 42.84 6.87 38.87 54.25 0.49 757 254 359 0.43 903.34 405.84 88.65 125.29 D005 CH-01 40 136C1 277.60 33.32 51.03 4.71 29.99 25.84 39.46 6.73 36.91 56.36 0.47 771 225 384 0.43 910.75 409.05 77.99 133.11 D006 CH-01 41 136C1 280.07 32.33 39.16 5.08 12.37 32.94 49.62 5.79 37.59 56.62 0.50 894 323 429 0.43 918.84 412.56 101.99 135.46 D008 103 Sample Sequence Borehole Sample Mid-Point Depth Sample Number Raw Dry, Ash-Free Moisture Ash Volatile Matter Fixed Carbon Moisture Volatile Matter Fixed Carbon Vitrinite Reflectance Langmuir Pressure Langmuir Volume Langmuir Volume (Dry, Ash-Free) Hydrostatic Pressure Gradient Depth Formation Pressure Gas Content (Raw) Gas Content (Dry, Ash-Free) Based on laboratory measurements Eddy (1982), reported by Stoeckinger (1991), evaluated the sorptive capacity for different coal types and presented it as a gas content versus depth graph (Figure 59). This graph was digitised and trend lines of the sorptive capacity of the coals created (Figure 60). It was possible to determine equations for these trend lines (Table 20) that could be used to calculate the sorptive capacities based on depth and quality. In all cases a R2 value greater than 0.9 was found. This is indicative of a strong correlation between the digitised data points and trend line. Figure 59 Relationship between rank, depth, and sorptive capacity (Eddy, et al., 1982). 104 Figure 60 Digitised trend lines of the relationship between rank, depth, and sorptive capacity after Eddy, et al. (1982). Table 20 Trend line equation calculations derived from the sorptive capacity graphs by Eddy, et al. (1982). Coal Rank Coal Rank Trend line Equation R² Abbreviation Anthracite ANT y = 192.21ln(x) - 451.44 0.9656 Low Volatile Bituminous LVB y = 141.59ln(x) - 316.94 0.9715 Medium Volatile Bituminous MVB y = 122.88ln(x) - 305.91 0.9887 High Volatile Bituminous A HVB-A y = 78.864ln(x) - 193.00 0.9824 High Volatile Bituminous B HVB-B y = 52.803ln(x) - 141.04 0.921 High Volatile Bituminous C HVB-C y = 30.948ln(x) - 69.666 0.9809 Subbituminous SBIT Y = 6.2975ln(x) - 7.8369 0.9575 By classifying the coal types in the Kubu samples subset, using the vitrinite reflectance and ash-free fixed carbon, volatile matter and moisture measurements it was possible to evaluate the correlation between the Langmuir isotherm and the Eddy (1982) trend line equations (Table 21). 105 The sorptive capacity values calculated using the Eddy (1982) equations differed from the isotherm determined values. For correlative purposes a ratio between the trend line and DAF isotherm results was calculated. The trend line values were generally less with one sample only proving 0.67 of the isotherm calculated value. Of the 2 trend line values higher than the isotherm results the highest ratio was 1.19 (Table 21). The distribution of the ratios was studied and it was found that 8 out of the 10 samples were within the range between 0.75 and 1.1 (Figure 61). This finding indicates that there is a high probability for either under or over estimation of the gas content values using the Eddy (1982) trend line equations. However, by utilising probabilistic simulation methods it is capable to compensate for this, specifically when looking at large datasets for the distribution determination. Figure 61 Correlation between the Langmuir isotherm and Eddy, et al. (1982) trend line equation gas content values. 106 Table 21 Langmuir isotherm and Eddy, et al. (1982) trend line equations gas content calculations for the Kubu sample subset. Gas Content Measured Gas Determined from Content Langmuir Isotherms (m) scf/T scf/T ft psi scf/T scf/T scf/T 12 134C7 463.00 CH-7-021 26.78 32.12 1519.01 672.43 105.97 172.20 High Volatile Bituminous - C y = 30.948ln(x) - 69.666 183.05 1.06 14 134C6 319.89 CH-6-002 21.78 42.05 1049.50 469.13 67.84 138.11 High Volatile Bituminous - C y = 30.948ln(x) - 69.666 108.84 0.79 15 134C6 329.12 CH-6-008 37.11 47.18 1079.78 482.24 124.49 163.82 High Volatile Bituminous - C y = 30.948ln(x) - 69.666 109.72 0.67 16 134C6 340.35 CH-6-013 39.94 49.05 1116.60 498.19 128.06 169.64 High Volatile Bituminous - B y = 52.803ln(x) - 141.04 166.80 0.98 25 135C4 451.11 CH-04-D7 56.73 67.23 1480.00 655.54 238.76 318.87 High Volatile Bituminous - A y = 78.864ln(x) - 193.00 288.99 0.91 28 136C3 364.85 CH-03-005 37.55 50.12 1197.00 533.00 159.21 229.16 High Volatile Bituminous - A y = 78.864ln(x) - 193.00 272.26 1.19 38 136C1 268.68 CH-01 D004 33.23 44.71 881.49 396.38 82.20 118.60 High Volatile Bituminous - C y = 30.948ln(x) - 69.666 103.44 0.87 39 136C1 275.34 CH-01 D005 33.13 45.05 903.34 405.84 88.65 125.29 High Volatile Bituminous - C y = 30.948ln(x) - 69.666 104.20 0.83 40 136C1 277.60 CH-01 D006 33.32 51.03 910.75 409.05 77.99 133.11 High Volatile Bituminous - C y = 30.948ln(x) - 69.666 104.45 0.78 41 136C1 280.07 CH-01 D008 32.33 39.16 918.84 412.56 101.99 135.46 High Volatile Bituminous - C y = 30.948ln(x) - 69.666 104.73 0.77 107 Sample Sequence Borehole Sample Mid-Point Depth Sample Number Raw Dry, Ash-Free Depth Formation Pressure Gas Content (Raw) Gas Content (Dry, Ash-Free) Coal Rank determined from vitrinite reflectance and ash-free fixed carbon, volatile matter and moisture measurements Stoeckinger (1991) Derived Trend Line Equation Gas Content Calculated using the Stoeckinger (1991) Derived Trend Line Equation (Dry, Ash-Free) Comparative Ratio (Trend line: Dry, Ash- Free Isotherm) The borehole information was evaluated and gas content values calculated using the Eddy (1982) trend line method. A complete database of information is shown in Appendix C. Table 22 shows the summarized calculated gas contents for each of the areas. In the absence of detailed regional evaluation data this proves to be a valuable tool for the resources assessment. Coal occurring at a depth of 30m or less was assigned a gas content of 1 scf/T. Table 22 Calculated gas contents for the coal seams using the trend line equations based on the coal qualities and depth. Country Area Source(s) Calculated Gas Content (scf/T) Zimbabwe Western Palloks (1984) 63 (1) 363 235 Areas Zimbabwe Entuba Palloks (1984) 125 (1) 486 221 Zimbabwe Lubu Palloks (1984) 28 (1) 180 73 Zimbabwe Sengwa Palloks (1984) 10 (1) 486 198 South Zimbabwe Sengwa Palloks (1984) 11 (1) 145 112 North Zimbabwe Lusulu Palloks (1984); 3 54 94 72 Mapani, et al. (2013); Padcoal (Pvt) Ltd (2011) Zimbabwe Wankie Palloks (1984) 2 176 447 291 Zimbabwe Gokwe Oesterlen & Lepper 1 160 182 172 (2005); Padcoal (Pvt) Ltd (2011) Zimbabwe Lubimbi Oesterlen & Lepper 1 (1) 93 73 (2005) Zimbabwe Busi Oesterlen & Lepper 1 18 20 19 (2005) Zimbabwe Tjolotjo, Oesterlen & Lepper 1 27 29 28 Sawmills, (2005) and Insuza Botswana Northeast Smith (1984), Anglo 39 (1) 34 23 Botswana Coal Botswana, (2010) Potgieter (2015) Values in brackets indicate values that were below the measurement limit. A default value of 1 was assigned to these estimates The full dataset evaluated can be viewed in Appendix B 108 Number of Data Points Evaluated Minimum Maximum Average 5.4.3. The Impact of Gas Saturation Levels within the Coal Seams Analysis of the digitised Shangani data (Appendix E) shows that there is a wide distribution of measurements throughout the sample set. When comparing the data from the trend line data interpreted from Eddy (1982) the maximum measurement in the area, in well C6-Wankie, generally coincides with the High Volatile Bituminous A trend line (Figure 63) inferring that the coal is either of slightly lower quality than in the main mining areas or that the coal is possibly under-saturated. Barker (2006) described the coal as being deposited in a zone with a thickness greater than 100m and of good quality. However, no mention of coking coal was made alluding that the coal is of a slightly lower quality than at the Wankie Mine. Table 23 shows the summarised descriptive statistics of the data that was digitised from the graph. These wide distributions of gas content values have been observed in the most Kubu Energy and Shangani Energy drilling campaigns are related to the gas saturation states within the coals. Faiz, et al. (2014) showed that the saturation of the coal seams in Botswana was related to the thermal maturity of the coal and that the gas was predominantly of biogenic origin. Figure 64 shows stratigraphic zonation, maceral composition, burial history and gas origin determined by isotopic analyses. Although the coals are vitrinite dominant they are generally immature and so incapable of generating thermogenic gas. The measurements with a higher maturity correlate to the proximity of dolerite intrusions and are localised phenomenon. Although these thermally enhanced samples did have higher gas content measurements as well as a mixed (thermogenic and biogenic) isotopic signature the saturation levels were still very low (Faiz, et al. 2014). 109 SEE APPENDIX E FOR FULL DATASET Figure 62 Desorption testing results from Zimbabwe (Barker, 2006). Table 23 Summarised statistics of the gas content data digitised from the Shangani Energy measurement data graph (after Barker, 2006). Summary Statistics of Gas Content Data in scf/T Mean 90.12 Standard Error 4.16 Median 70.69 Mode 29.09 Standard Deviation 73.55 Range 408.34 Minimum 0.63 Maximum 408.97 Count 313 110 Figure 63 Digitised gas contents from the Shangani Energy measurement data graph compared to the maximum sorptive capacity (after Barker, 2006 and Eddy, et al., 1982). 111 a) Stratigraphic zonation of the Permian coal seams b) Maceral composition of the coals c) Burial history chart for the Permian d) Isotopic analysis showing the thermogenic dominance Figure 64 Evaluations of the Permian coals collected during the Kubu Energy exploration campaign in Botswana (Faiz, et al., 2014). 112 The estimation of saturation levels in this study forms an important basis of the gas content component as the trend line calculated gas contents assume 100% saturation levels. The information digitised from the Shangani presentation show that there is a wide range of saturation levels in Zimbabwe with the majority of the measurements in well C6-Hwange indicating a saturation level less than 75% (Figure 65). Saturation levels in the the Kubu data subset (Table 24) is evidence of generally under-saturated coal (Faiz, et al., 2014; Kubu Energy, 2014; and Potgieter, 2015). Table 25 demonstrates the effect of saturation levels varying from 100% to 25% on the calculated gas contents. These drastic changes in the gas content will have a notable effect on the final resource determinations as well as the postulated production profiles and economic evaluations that would be completed for a project as part of the New Ventures Screening Process. Figure 65 Gas measurement data from the Shangani graph plotted on theoretical sorptive capacities of a high volatile bituminous A coal type (after Barker, 2006 and Eddy, et al., 1982). 113 Table 24 Coal saturation levels of the Kubu data subset (after Kubu Energy, 2014). Sample Analyses Measured Isotherm Data Gas Content Sample Mid-Point Borehole Depth Sample Number (m) scf/T scf/T scf/T scf/T scf/T % % 12 134C7 463.00 CH-7-021 26.78 32.12 105.97 172.20 183.05 30.31 17.54 14 134C6 319.89 CH-6-002 21.78 42.05 67.84 138.11 108.84 61.99 38.64 15 134C6 329.12 CH-6-008 37.11 47.18 124.49 163.82 109.72 37.90 43.00 16 134C6 340.35 CH-6-013 39.94 49.05 128.06 169.64 166.80 38.31 29.41 25 135C4 451.11 CH-04-D7 56.73 67.23 238.76 318.87 288.99 28.16 23.26 28 136C3 364.85 CH-03-005 37.55 50.12 159.21 229.16 272.26 31.48 18.41 38 136C1 268.68 CH-01 D004 33.23 44.71 82.20 118.60 103.44 54.39 43.23 39 136C1 275.34 CH-01 D005 33.13 45.05 88.65 125.29 104.20 50.82 43.23 40 136C1 277.60 CH-01 D006 33.32 51.03 77.99 133.11 104.45 65.43 48.86 41 136C1 280.07 CH-01 D008 32.33 39.16 101.99 135.46 104.73 38.39 37.39 114 Sample Sequence Raw Dry, Ash-Free Gas Content (Raw) Gas Content (Dry, Ash- Free) Gas Content Calculated using the Eddy, et al., (1982) Derived Trend Line Equation (Dry, Ash-Free) Saturation levels calculeted from Isotherm Data (DAF) Saturation levels calculated from Trendline Equations (DAF) Table 25 The effect of gas saturation state of the coal on the calculated gas content data using the trend lines derived from Eddy, et al. (1982). Country Area Source(s) Estimated Gas Content (scf/T) Fully 75% Saturated 50% Saturated 25% Saturated Saturated Zimbabwe Western Areas Palloks (1984) 63 (1) 363 235 (1) 272 176 (1) 182 117 (1) 91 59 Zimbabwe Entuba Palloks (1984) 125 (1) 486 221 (1) 365 166 (1) 243 110 (1) 122 55 Zimbabwe Lubu Palloks (1984) 28 (1) 180 73 (1) 135 55 (1) 90 37 (1) 45 18 Zimbabwe Sengwa South Palloks (1984) 10 (1) 486 198 (1) 365 149 (1) 243 99 (1) 122 50 Zimbabwe Sengwa North Palloks (1984) 11 (1) 145 112 (1) 108 84 (1) 72 56 (1) 36 28 Zimbabwe Lusulu Palloks (1984); Mapani, et 3 54 94 72 41 71 54 27 47 36 14 24 18 al. (2013); Padcoal (Pvt) Ltd (2011) Zimbabwe Wankie Palloks (1984) 2 176 447 291 132 335 218 88 223 146 44 112 73 Zimbabwe Gokwe Oesterlen & Lepper 1 160 182 172 120 137 129 80 91 86 40 46 43 (2005); Padcoal (Pvt) Ltd (2011) Zimbabwe Lubimbi Oesterlen & Lepper (2005) 1 (1) 93 73 (1) 70 55 (1) 46 37 (1) 23 18 Zimbabwe Busi Oesterlen & Lepper (2005) 1 18 20 19 13 15 14 9 10 9 4 5 5 Zimbabwe Tjolotjo, Sawmills, and Oesterlen & Lepper (2005) 1 27 29 28 21 22 21 14 14 14 7 7 7 Insuza Botswana Northeast Botswana Smith (1984), Anglo Coal 39 (1) 34 23 (1) 26 17 (1) 17 12 (1) 9 6 Botswana, (2010) Potgieter (2015) Values in brackets indicate values that were below the measurement limit. A default value of 1 was assigned to these estimates The full dataset evaluated can be viewed in Appendix B 115 Number of Data Points Evaluated Minimum Maximum Average Minimum Maximum Average Minimum Maximum Average Minimum Maximum Average Figure 66 is a distribution curve constructed from the measured, digitised and calculated gas content values. All calculated values were subjected to saturation corrections of 100%, 75%, 50% and 25% prior to the construction of the histogram. A statistical analysis of the data showed is summarised in Table 26. Figure 66 Distribution of gas content values from the calculated, digitised and measured datasets. Table 26 Summarised statistics measured, digitised and calculated gas content values with incorporating the effect of saturation levels of the coal. Summary Statistics of Gas Content Data in scf/T Mean 141 Median 97 Mode 1 Standard Deviation 139 Range 774 Minimum 1 Maximum 775 Count 2642 116 5.5. Resource Evaluation GeoX is purely a probabilistic volumetric calculator. The software has a CBM component used in this evaluation. Users have the ability to set the parameters used for the resource estimations based on two methods, the first is called the direct method where the gas content information is directly entered into the system as opposed to the indirect method where the gas content is calculated using Langmuir isotherm volumes and pressures. The latter is a very good method, however, it is heavily dependent on the acquisition of reliable desorption and isotherm data that is not readily available across the study area. Although the distribution function compensates for anomalously high and low values to an extent, it is advised that the input data be evaluated further and a narrower band of values be select and used for the calculations. The coal thickness (h), coal density (RHOB(c)) and gas content (G(c)) data was evaluated further to determine the final GeoX inputs. The distribution of the coal thickness data was lognormal with 98% of the data falling in the range between 1m and 17.92m (Table 27). The Kubu Energy (2014) wireline density distribution was used as an analogue for the study area. The data evaluation (Table 27) indicated that 93% of 13 427 measurements were distributed between density values of 1.3g/cm³ and 1.75g/cm³ with the mode being 1.70 g/cm³. The analysis of the measure, digitised and calculated gas content database established that 98% of the measurements are between 1scf/T and 496scf/T (Table 27). For this evaluation the surface extent of 134 666km² occupied by Karoo Supergroup rocks over the study area was used as a constant for the Area (A) component of the resource calculation. Table 28 summarises the inputs and modelled distributions used during the GeoX estimation. 117 Table 27 Summary of original and filtered data inputs used in GeoX. Parameter Data Descriptive Statistics (All Distribution Curve (All Data) Descriptive Statistics Distribution Curve (Filtered Data) Retained Data) (Filtered Data) During Filtering Mean 9.58 Mean 9.39 Median 9.66 Median 9.51 Mode 11.66 Mode 11.66 Coal Thickness Standard Deviation 3.67 Standard Deviation 3.36 98% (h). Range 22.65 Range 16.92 Minimum 1.00 Minimum 1.00 Maximum 23.65 Maximum 17.92 Count 250 Count 246 Mean 1.53 Mean 1.55 Median 1.55 Median 1.56 Mode 1.65 Mode 1.70 Coal Density Standard Deviation 0.14 Standard Deviation 0.12 96% (RHOB(c)) Range 0.64 Range 0.45 Minimum 1.11 Minimum 1.30 Maximum 1.75 Maximum 1.75 Count 13427 Count 12466 Mean 141 Mean 129 Median 97 Median 93 Mode 1 Mode 1 Gas Content Standard Deviation 139 Standard Deviation 116 94% (G(c)) Range 774 Range 495 Minimum 1 Minimum 1 Maximum 775 Maximum 496 Count 2642 Count 2578 118 Table 28 Summary of the inputs used in GeoX. Parameter Area Coal Thickness Coal Density Gas Content (A) (h) (RHOB(c)) (G(c)) Unit km² m g/cm³ scf/T Distribution Constant Stretched Beta Stretched Beta Lognormal Based on Median Area 134666 Minimum 1.00 Minimum 1.3 Minimum 1 Maximum 17.92 Maximum 1.75 Maximum 496 Mode 11.66 Mode 1.70 Median 93 119 A Monte Carlo simulation with 10000 iterations was used to calculate the regional resource estimates. This simulation provides the ability to report values for the P10 (10% probability, least likelihood), P50 (mid-case), P90 (90% probability, highest likelihood). The resource evaluation results show a wide distribution of probable values (Table 29 and Figure 67). This is indicative of a poorly understood region with a great deal of assumption as opposed to good exploration data. Table 29 Result of the GeoX volumetric resource calculation showing the P10, P50, Pmean and P90 values. Estimated Resource Size INCREASING PROBABILITY OF OCCURRENCE P10 Pmean P50 P90 Billion Cubic Feet (Bcf) 60196 29582 23105 6917 Trillion Cubic Feet (Tcf) 60.1 29.5 23.1 6.9 Billion Cubic Metres (Bm³) 1595 784 612 183 Figure 67 Distribution of the results of the GeoX Monte Carlo resource calculation. To fully evaluate the significance of the resource estimates over the study area it is important to compare it to other CBM basins globally. As the basins all differ in surface extent the best comparison tool is to express the values as a concentration 120 expressed as billion cubic feet per square kilometre expressed as Bcf/km2, calculated using the formula shown in Equation 6. RD = GP50 A Where: RD = Resource Density Estimation in Bcf/km² GP50 = P50 Resource Estimate in Bcf A = Surface area in km² Equation 6 Resource density calculation method. The Study Area has a P50 Surface Area (A) 134 666 km² and P50 Resource Estimate (GP50) of 23 105 Bcf, equating to a resource density of 0.17 Bcf/km². This density was compared to a number of basins in Canada and the USA (Table 30) for comparative purposes. The major basins in Canada and the US have a significantly higher resource density than that of the Study Area indicating a lower prospectivity for CBM. Once more reliable regional data becomes available it will be possible to update this evaluation, however, from previous investigations within the region the general exploration and development potential is low and to date not a single project comparable to the North American basins have been found (Potgieter, 2015). Table 30 Resource densities for the basins used in this (after APF Energy, 2004). Basin Country Resource Density (Bcf/km²) Study Area (Kalahari Karoo and Mid-Zambezi Botswana and 0.06 - 0.3 Basins Zimbabwe Range: P90 to P10 P50 – 0.18 San Juan USA 5.8 -6.8 Black Warrior USA 3.9 - 4.8 Uinta USA 5.0 - 6.0 Powder River USA 0.8 - 1.4 Raton USA 3.9 - 4.6 Alberta plains shallow Canada 0.6 - 0.9 Alberta plains deep Canada 1.2 - 2.5 121 6. CHALLENGES WITH DATA ACQUISITION AND MITIGATION MEASURES FOR FUTURE EXPLORATION The primary challenge with the assessment of the study area was the availability of reliable gas content data. If regional data collection and reporting was standardised it would be possible to assess the area with a greater amount of certainty. This section will outline some of these challenges and suggest an achievable guideline for field data collection during CBM exploration programmes in Southern Africa. As there are no Southern African standards available, companies have been following international standards (Potgieter, 2015). The most widely applied standards for the determination of gas in coal are the Australian (AS 3980-1999) and American (D7569-10) standards (Standards Australia, 1999 and ASTM International, 2010). From personal experience the data gathering procedures in the two standards are not always practical in remote exploration areas such as the study area regarding to cost and equipment availability (Potgieter, 2015). This led to companies inconsistently following sections of the standards compromising the data quality and reliability (Potgieter, 2015). 6.1. Data to be Acquired During Exploration Programmes When evaluating CBM resources during a dedicated exploration programme it is necessary to collect the following data: • Coal thickness measured from wireline logs. • Stratigraphic depths measured during the drilling and refined using the wireline logs. • Formation temperature from wireline logs. • Proximate coal analysis. • Gas content measured from core desorption. • Gas saturations calculated from the comparison of the measured gas content analyses with the maximum gas holding capacity derived from adsorption isotherm measurements. • Gas composition measurements using gas chromatography. 122 Additional data used to further determine the reservoir production capability and gas origin that will impact on the deliverability and ultimate estimated recoverability of the CBM Field include: • Gas isotope samples for the determination of gas sourcing (biogenic vs thermogenic). • Coal formation permeability and pressure gradient measured in situ using Drill Stem Tests (DSTs) or Injection Fall-off Tests (IFTs). 6.2. Guidelines for CBM Exploration Data Collection, Sampling and Reporting The following guidelines will cover the aspects listed in Table 31. For illustrative purposes a hypothetical borehole will be used (Figure 68) that is applicable to a range of different deposits and formations. Table 31 Aspects addressed as part of the guidelines for CBM exploration data collection and sampling. 1. Programme Planning and Logistics 2. In-Field Sampling 3. Gas Content Measurements 4. Wireline Logging 5. Post Desorption Sample Analyses 6. Data Reporting 123 Figure 68 Well stratigraphy and coal measure zonation as used in the guidelines. 124 HYPOTHETICAL WELL: STRATIGRAPHY AND COAL MEASURE ZONATION Depth Stratigraphy Depth Lithology Coal Zonation Description 0 200 UPPER MARKER Carbonaceous mudstones with thin dull coal stringers. 20 205 40 210 60 215 ZONE 4 Bright coal with interbedded carbonaceous mudstone. Calcite in fractures and cleats. 80 220 100 Overburden 225 120 230 ZONE 3 Dull coal with interbedded carbonaceous mudstone. Abundant pyrite bands. 140 235 160 240 180 245 200 250 ZONE 2 Bright coal with interbedded carbonaceous mudstone towards top and base. 220 255 240 260 Coal Measures 260 265 280 270 300 275 Upper coal is dull with pyrite bands. Bright coal in ZONE 1 towards base. Dark, carbonaceous mudstone separates the upper and lower coal units. Minor calcite on fractures Pre-Coal Measure and cleats. Sediments 320 280 340 285 Precambrian Basement LOWER MARKER Carbonaceous mudstones with thin dull coal stringers. Frequent pyrite bands 360 290 Lithology Legend Mudstone Carbonaceous mudstone Siltstone Sandstone Carbonaceous mudstone with coal stringers Coal with interbedded carbonaceous mudstone Dull coal Bright coal 6.2.1. Programme Planning and Logistics When planning an exploration programme it is imperative to plan for a CBM programme and not a modified coal exploration campaign. The approach with respect to data gathering is greatly different and will come at higher costs. 6.2.1.1. Drilling Techniques The preferred drilling technique for CBM exploration should be wireline core drilling as this is the fastest method for getting core to surface from depth. HQ3 and PQ3 triple tube coring systems (Figure 69) are best suited for desorption sampling. The triple tube system causes the least damage to the core during extraction from the barrel and inner tube. Figure 69 Coring sizes (Sandvik Mining and Construction, 2015). 125 6.2.1.2. Desorption Equipment The contractor appointed to manage the desorption testing of the samples needs to be informed of the core size well in advance of mobilisation. The desorption equipment selected should be sized correctly for the project. It is important to minimize the amount of free space around the core. Depending on the remoteness of the project area it may be necessary to ensure the contractors maintain full redundancy on all essential equipment and specifically on items that may have a long lead replacement schedule such as chromatography equipment. 6.2.1.2.1. Desorption Canisters Desorption canister (Figure 70) lengths differ and may range from 30cm to 1m. When dealing with barcoded coal sequences as found in north-eastern Botswana filling a 1m canister from a three metre core run may be tricky, whereas 30cm canisters often fail to capture all available data in more discreet seams as found in Zimbabwe. A canister length of approximately 60cm has proven to work very well in Southern Africa (Potgieter, 2015). These canisters can be made of various materials such as steel, aluminium or PVC and the closing mechanism can be bolted, threaded, clamp (Figure 71) or glued in the case of PVC (Spears, et al., 2014 and Eddy, et al., 1982). The PVC canisters are cheaper to manufacture, however, they remain single use equipment. The preference will be either steel or aluminium with an o-ring in the cap or on the canister for increased seal. Some prototypes of aluminium canisters with double lead threading have been developed but not yet tested (Potgieter, 2015). 126 Figure 70 Test sample canister (Stoeckinger, 1991). Figure 71 Clamp type aluminium HQ3 canisters (Potgieter, 2015). 127 6.2.1.2.2. Canister Spacers If it is expected that some thin or barcoded coal zones may be intersected it may not be possible to fill an entire canister with a coal sample. In such cases it is necessary to place spacers in the canisters. Spacers need to be made of a substance impermeable and of which the density is consistent. High density polyethylene (HDPE) works very well as spacers due to its nature and ability to mould or mill billets to match the required specifications. The spacer billets can be prepared in two ways: 1. Supply the HDPE billets in 1m lengths and cut the appropriate lengths required on site using a hack saw. This process could be time consuming and actually impact the quality of the desorption data; 2. Have the HDPE billets pre-prepared in specific sizes to be used as spacers. It is possible to use a combination of 1cm, 5cm and 10cm billets for various spacer sizes. When ordering the spacers it is very important that the density and weight is known and that the billets are manufactured to have the same diameter as the core. 6.2.1.2.3. Water Baths and Hot Boxes The samples need to be desorbed at the temperature of the formation at the depth where the sample was taken. To ensure this temperature is maintained the desorption canisters need to be placed in either a heated water bath or a hot box with thermal lamps. If possible a water bath (Figures Figure 72 and Figure 73) should be used as water conducts and maintains temperature better than the air in the hot boxes. If the plan is to construct water baths in-house bear in mind that the heating element must be of sufficient size to heat the water evenly and rapidly. An adjustable thermostat must be added to control the water bath temperature. 128 Figure 72 Water bath (GEO Data, n.d.). Figure 73 Desorption canisters in a water bath (Waechter, et al., 2004). 6.2.2. In-Field Sampling The number of samples taken as part of a Greenfield exploration programme can be a limiting factor. More often than not costs override the value of sampling all the coal 129 encountered in the initial exploration boreholes. The ideal would be to sample all coal in at least the first couple boreholes to establish a baseline, especially if there is little or no information available regarding the coal deposits in the area. It is very rare that an exploration team is afforded this opportunity or that there is no regional information available for an area. 6.2.2.1. Sampling Strategy The hypothetical borehole and coal sequence (Figure 68) will be used to illustrate a typical sample collection approach when a limited number of desorption canisters may be used. In this scenario the maximum number of samples that may be taken is thirty (30). The sample collection strategy outlined in Figure 74 was developed to analyse the thickest and brightest coal zones more rigorously than the dull, thin and barcoded zones. When limited in the number of samples that can be taken it is advised to have a number of samples, around 10%, as contingent samples. These can either be reserved for specific zones, as in the hypothetical case, or in the event that an unexpected horizon, such as a 30cm bright stringer in a barcoded sequence or thicker than expected coal zone, is encountered. 6.2.2.2. Sample Identification and Collection Time is of the essence when collecting desorption samples. As the core is brought to surface it loses gas and it is of utmost importance to minimise the time it takes to bring the core to surface, extract it from the core barrel, identify the samples and place in the desorption canisters (Waechter, et al., 2004; Potgieter, 2015 and Halliburton, 2008). A field exploration geologist with CBM exploration experience is essential for this phase as long delays may have a detrimental effect on the data quality. Table 32 demonstrates the sequence of events and points at which time recordings have to be taken during the sample collection process. 130 Figure 74 Desorption sample collection strategy. 131 Lithology Legend Mudstone Carbonaceous mudstone Siltstone Sandstone Carbonaceous mudstone with coal stringers Coal with interbedded carbonaceous mudstone Dull coal Bright coal Table 32 Sampling sequence of events. SEQUENCE ACTION TIME MEASUREMENT DESCRIPTION 1 Start of coring run This is taken as the point when the coring bit starts cutting the core. 2 Coring mid-point Start recording time In Southern Africa 3m core barrels are used most often. In this case the mid-point will be at 1.5m. This is the point at which time recording must start, referred to as time zero (T0) (Standards Australia, 1999). 3 End of coring run This is taken as the point when the core assembly has penetrated the full barrel length (3m). 4 Core separation This process is where the base of the cut core is broken off the underlying formation by the drill rig 5 Core barrel collection The wireline overshot is deployed to collect the core barrel (Figure 75). 6 Core extraction The core barrel is brought to surface using the wireline winch mounted on the drill rig. 7 Core removal from the Once on surface the core inner barrel and catcher are unscrewed and the inner tube system is removed. The inner tube is pumped out of the inner barrel inner barrel using a water plug and hydraulic pressure this minimises the amount of damage to the core. By using the triple tube system the inner tube is a split system than can be open with minimal effort further reducing time delays and damage to the core. 8 Lithological The core has to be inspected for standard core recovery measurements and a brief lithological description taken. During this description potential description of the core samples need to be identified and marked out. It is advised to have desorption canisters on hand ready to be filled during the description process (Figure 76). Always ensure that the canister seal properly to prevent leakages prior to this phase. 9 Sample Collection The samples identified during the lithological description phase need to be verified with the sampling strategy to prevent over or under sampling. The samples need to be cut from the core using either a hand held sampling saw or bolster and hammer. Bolsters work well in the Karoo cores. A useful tip with this phase is to have some halved PVC tubing, called a slip, on hand to place the samples in. The weight of the PVC tube needs to be written on in indelible ink as the sample has to be weighed prior to placing it in the desorption canister (Figure 77). The weight of the sample is important as gas content is expressed as volume per weight. If a significant amount of the sample is crushed the readings may be affected and in such cases it is best to not take the sample (Standards Australia, 1999). 10 Transfer to desorption The selected sample on the slip can now be transferred to the desorption canisters. Ensure that all the material on the slip gets transferred to the canister canister. If a spacer was required the required length of spacer needs to be placed into the canister below the sample. Once the sample is in the canister the canister can be sealed. 11 Prepare canister for Once sealed the canisters can be moved to the hot box or water bath. Jin, et al. (2010) showed that oxygen in the canister can affect the gas the water bath or composition measurements and as a result of this it is required to add a head space filler to the canister. The ASTM and AS standards provide for hotbox the addition of head space purging substances. The ASTM standards favours the use on an inert gas such as helium for this, however it is acceptable if distilled or formation water is used (ASTM International, 2010). If a gas is used the cap of the canister need to be prepared with a purge valve (Figure 78). In cases where the canisters do not allow for gas purging and formation water from nearby boreholes is not available distilled water must be used. 12 Place canister in Stop recording time The desorption canister is transferred to the hot box or water bath that has been pre-heated to the required reservoir temperature. This hotbox or water bath temperature can be obtained from the wireline logging. If no logging has taken place the temperature can be estimated based on the average surface temperature and geothermal gradient of the exploration area. 132 Figure 76 Sample identification and collection (CBM Asia Development Corporation, 2012) Figure 77 Coal sample selected for desorption on digital scale (Potgieter, 2015) Figure 75 The wireline coring system collection mechanism (Massenga Drilling Rigs, n.d.) Figure 78 Desorption canister with purge and thermocouple valve (GEO Data, n.d.) 133 6.2.3. Gas Content Measurements Gas content determination of the coal is comprised of three components 1) measureable gas, 2) lost gas and 3) residual gas. Each component is determined by different techniques as outlined in this section. The cumulative amount of gas that is desorbed from the coal is compared to the weight of the sample to express the gas content as a factor of volume to weight. 6.2.3.1. Measureable Gas The measurable gas (Q2) refers the physical amount of gas that is desorbed from the coal. These measurements are taken from the desorption canisters by opening the valve on the canister and having the gas displace water in a measuring cylinder. To facilitate easier reading of the measurements food colouring can be added to the water. The Australian Standard allows for the measurements to be taken either based on time or volume of gas. For field measurements it is advised to take all measurements based on time. When taking the measurements there are two possible configurations. The first is a single canister measuring system where the canister either has to be removed from the water bath (Figure 79) or the measuring cylinder tube is connected to each canister individually. This is cumbersome on understaffed projects and by removing the canisters from the water bath the sample temperature is disturbed. The second and preferred method is the have multiple measuring cylinders each connected to a specific desorption canister (Figure 80). With this configuration the geologist or assistant reads the desorbed volumes from the cylinders at specific time intervals without disturbing the samples. An added advantage of this configuration is that the cumulative volumes can be read directly rather than calculated based on point values reducing the chance for errors. 134 Figure 79 Single sample desorbed gas content measuring apparatus (Weatherford Laboratories, n.d.). Figure 80 Continuous multiple sample desorbed gas content measuring apparatus (CSG Exploration & Production Services, n.d.). 135 Coal samples do not desorb at a fixed rate and as a result the measurements early on during the desorption process has to be more frequent than towards the end (Figure 81). Figure 81 Cumulative measureable desorbed gas curve (Faiz, et al., 2013). In Southern Africa the first 14 days of desorption is the key period when measurements have to be taken both often and at uniform intervals on all samples (Potgieter, 2015). With previous projects this sampling period was sub-divided into a number of time sections. Each timing section had different measurement intervals as outlined in Table 33. The end of desorption is regarded as the point where the sample equilibrates and the curve flat lines. A practical view of this point is when no additional gas is desorbed from the sample for a period of 5 days. As the project progresses it may be possible to determine the general number of days required for equilibrium e.g. 28 days. Once this timeframe is known a fixed time desorption programme can be developed. 136 Table 33 Suggested desorption measurement intervals (Potgieter, 2015). Time Section (after T1) Measurement Interval Samples to be Taken Gas Composition Isotope 1. 0 – 10 minutes 1 minute 2. 10 minutes – 1 hours 5 minutes 3. 1 – 2 hours 15 minutes 4. 2 – 6 hours 30 minutes 5. 6 – 12 hours 1 hours 6. 12 hours to 1 day 2 hours 7. 1 – 2 days 4 hours Sample Sample 8. 2 – 5 days 8 hours 9. 5 – 14 days 12 hours 10. 14 days onwards 1 day Gas composition is an important aspect as CBM is not pure methane but a mixture of gasses, mainly methane, carbon dioxide and nitrogen. Resource estimations are based on total CBM, however sales gas will only be methane. When collecting the sample it is important to ensure the pure desorbed gas is sampled. To prevent any possible contamination the best point to take the gas sample is after about 2 days (Table 33). Gas composition samples need to be taken on each canister. To fingerprint the origin of the gas (biogenic vs. thermogenic) isotope samples need to be collected. Isotope samples are collected in metal vessels known as IsoTubes (Figure 82 IsoTube gas sampling receptacle ) or gas tight packets. Due to logistics and 137 costs it is not always practical to sample every desorption canister for isotope analysis, however, it is important to generate a profile for the borehole and at least one isotope sample per zone is recommended. The samples should be taken shortly after the gas composition sampling (Table 33). Figure 82 IsoTube gas sampling receptacle (Fieldwork Group, n.d.). 6.2.3.2. Lost Gas Lost gas (Q1) volumes are determined by extrapolating the first few hours of reading back to T0 (Waechter, et al., 2004). Waechter, et al. (2004) found that the accuracy of this extrapolation is higher where the sample collection time is faster and the initial desorption measurements were taken at a higher frequency as well as based on extended desorption measurements (Figure 83). A best fit polynomial method over extended time has shown to provide a superior fit (Figure 84) and more accurate Q1 determination (Waechter, et al., 2004). 138 a) Lost gas projection: linear fit, 2.8 hours of readings. b) Lost gas projection: linear fit, 6.8 hours of readings. c) Lost gas projection: polynomial fit, 6.8 hours of readings. Figure 83 Curve fit lost gas estimations (Waechter, et al., 2004). 139 Figure 84 Comparison of linear and polynomial fits in a coal with high gas content and high diffusion rate over a 4.4 hour period (Waechter, et al., 2004). 140 6.2.3.3. Residual Gas Once the core desorption has been completed it is necessary to determine the residual gas content (Q3). The residual gas content is the amount of gas that is not extracted from the coal sample during the desorption analysis. To measure the residual gas content the core has to be removed from the desorption canister. Once the core is removed it must be cut in half using a slabbing saw (Figure 85). Half of the core will be kept for further coal analysis and half will be used to determine the Q3 content. In some cases only a quarter of the core is used for Q3 measurements, this requires a second slab on one of the core halves. The Q3 subsample has to be weighed again and placed in a gas tight Mill Pot and placed in a shaker (Figure 86 and Figure 87). The sample must be crushed to the point where 95% of the material will pass through a 212μm mesh (Standards Australia, 1999). The amount of gas liberated during the crushing is measured and reported as the residual gas content. Standards Australia (1999) requires to samples to be measured and compared. Equipment availability does not always allow for this. Figure 85 Core slabbing equipment (GeoGas Pty Ltd, 2016). 141 Figure 86 Residual gas content measurement milling canister (Weatherford Laboratories, n.d.). Figure 87 Residual gas mill pot in a shaker (GeoGas Pty Ltd, 2016). 6.2.3.4. Total Gas Content The total gas content of a sample is defined as the sum of the measurable gas, lost gas and residual gas. When the final data is reported the individual components and total gas content is provided. If the proximate analysis has been completed by the same contractor as the desorption evaluation the dry, ash-free gas content is often reported as part of the desorption summary sheet (Figure 88). 142 Figure 88 Desorption summary sheet (Kubu Energy, 2014). 143 6.2.4. Wireline Logging Wireline compensated density logs should be used as the primary coal identification tool. Along with the dual density tool a natural gamma, used for stratigraphic delineation, downhole temperature and, a multi-arm calliper, used to determine the borehole geometry, must be run as the minimum logging suite. When running the density tool it is important to log at rates slower than 4m/min and maintain a constant logging speed. Although the density tool provides a calliper log along with the density log the multi-arm calliper is a good independent gauge for the accuracy of the density compensation. The temperature log is used to 1) determine the formation temperature and 2) indicate any possible water inflows. A number of the multi-arm calliper tools has a temperature sonde included, however if this is not the case a separate temperature sonde needs to be added to the logging suite. Additional tools such as the sonic, resistivity, neutron, spontaneous potential, full waveform sonic and televiewer may be run depending on the requirement for additional petrophysical evaluations and budget constraints. Table 34 is summary of a number of tools showing tool descriptions and nominal logging speeds for a comprehensive logging suite as provided by Farr (2012). It is very important to select a logging unit capable of reaching the operations. For a basic logging suite a 4x4 vehicle, like a Landcruiser, will suffice, however for more comprehensive logging suites in large diameter, deep boreholes, larger, purpose built trucks may be required (Figure 89). 144 Table 34 Wireline logging tool specifications and logging speeds (Farr, 2012). Basic Tool Suite Information and Descriptions Tool Name Tool Description Logging Speed Dummy Weighted pipe to check if borehole has collapsed. 15m/min Three-Arm This is a three-arm calliper configuration used to measure the diameter of the borehole. It can be used in both open 10m/min Calliper and cased holes. Compensated The Compensated Density Logging Tool uses the two focused density detectors to compute borehole compensated 3m/min Density density real time while logging. No post processing is required to produce compensated bulk density. Additionally, the tool also records natural gamma, calliper and focused guard resistivity. Acoustic The Acoustic Televiewer takes an oriented "picture" of the borehole using high-resolution sound waves. This acoustic 1m/m Televiewer picture is displayed in both amplitude and travel time. This information is used to detect bedding planes, fractures, and other hole anomalies without the need to have clear fluid fill in the boreholes. The televiewer digitizes 256 measurements around the borehole at each high-resolution sample interval (.005 meters/.02 feet). This data is oriented to North and displayed real-time while logging using the Visual Compu-Log software. Analysis includes colour adjustment, fracture dip and strike determination, and classification of anomaly. It allows information to be displayed on the graphical screen, plot, and in report format. Optionally, the tool can be equipped with a natural gamma sensor. Full Wave The Full Wave Sonic Tool contains a single transmitter and dual receiver to record formation travel times. The full wave 2m/min Sonic form data is also recorded simultaneously, along with near and far travel times, borehole compensated delta time, calculated sonic porosity, receiver gains, near/far amplitudes and natural gamma. The sonic or acoustic log uses the basic principle of sound waves traveling through media. The Century sonic system uses a single transmitter and dual receiver system for recording the travel times of the formation. The receivers are spaced (2 and 3 ft.) from the transmitter. Therefore, a 0.3 m (1ft.) calculation can be made to measure this interval transit time. Spontaneous The Spontaneous Potential Resistivity Tool is a multi-parameter resistivity tool primarily used for water well logging and 5m/min Potential monitoring boreholes. The tool records nine different parameters simultaneously in one pass of the borehole. The nine Resistivity parameters are the following: natural gamma, spontaneous potential, single point resistance, 16” normal resistivity, 64” normal resistivity, 48” lateral resistivity, fluid resistivity, temperature, and differential temperature. Multi- The Multi-Parameter E-Log, Neutron Logging Tool was developed to replace the E-Log Tool (9055) which was Parameter E- historically Century's most popular tool. The tool duplicates all parameters on the 9055 while adding the 16’ normal, 64” Log, Neutron normal, and lateral resistivities. The natural gamma circuit features a low dead time and the ability to measure very high count rates making it a favourite for uranium logging. The tool records ten different parameters simultaneously in one pass of the borehole. The ten parameters are the following: natural gamma, spontaneous potential, single point resistance, 16” normal resistivity, 64” normal resistivity, 48” IateraI resistivity, neutron-neutron, temperature, delta temperature, slant angle (tilt) and azimuth (bearing). Slant angle, azimuth, and natural gamma are optional. 145 a) Light weight wireline logging unit (Weatherford, 2016) b) Weatherford's small-footprint slimline logging platform mounted on a c) Light weight wireline logging unit in Mozambique (Weatherford, 2007) 1.5-ton truck (Weatherford, 2007) d) Heavy duty logging unit (Farr, 2012) e) Medium duty logging unit (Farr, 2012) Figure 89 Examples of wireline logging units. 146 6.2.5. Post-Desorption Sample Analyses The post-desorption sample analyses are subdivided into two categories, 1) basic analyses to be conducted on all desorption samples and 2) specialised analyses to be conducted on selected samples only. 6.2.5.1. Basic Analyses All desorption samples must have proximate analyses conducted on them, as this is the key to the DAF gas content determinations and coal quality determination. Grain density measurements have to be completed on each sample. 6.2.5.2. Specialised Analyses The specialised analyses referred to in this section are isotherm and petrography analyses. When selecting samples for isotherm analysis it is important to have a representative distribution of the possible saturation values. Due to cost constraints it is rarely possible to conduct specialised analyses on all desorption samples. For representative sampling, the approach should be to have at least one sample over each zone and two contingent samples to test the heterogeneity in the most prospective zones (Figure 91). It is required to quarter the core samples for this method. The quarter to be retained for possible isotherm analysis must be stored in a manner to prevent any core degradation. Storage requirements will be provided by the laboratory responsible for the isotherm analyses. The measured gas content values can be used to determine which samples to select, where the high gas content samples are compared to low gas content samples. This method has the potential to bias the readings toward a specific saturation state of the coal. Comparatively lower gas content values are often excluded from the isotherm sampling programme. However, lower gas contents at higher saturation states could 147 be more productive across the field as shown in Figure 90. In the figure, both samples are under-saturated, however, the level of under-saturation in a lower quality coal is of such a nature that it may be able to produce gas quicker than a higher quality coal. Figure 90 Hypothetical production dynamics of 2 coal types and similar depths. It is advised to review the DAF gas content values of all samples in a zone and select the samples with values as close to the mode value as possible. This method works well in zones with a fairly uniform coal type and data distribution. In cases where a zone shows a great deal of heterogeneity with regards to the coal qualities and gas content values the data has to be evaluated further to determine the best 148 representation for the zone. Such a zone would typically require more than one sample analysed. For the selection of the samples a ratio of DAF gas content to DAF fixed carbon can be used (Figure 92). This ratio provides a qualitative comparison of the sorpotive capacity of every percent of fixed carbon of the coal. This ratio can be assumed as a proxy for the relative saturation states, but does not replace the isotherm analyses in any way. Due to different pressures encountered within different zones this ratio is not applicable for the comparison across zones. Higher ratios indicate coals where the fixed carbon desorbs greater volumes of gas per unit of carbon and the opposite is true for lower ratios. By comparing these base indices it is possible to eliminate bias in selecting subsamples related to the measured gas contents. An evaluation of this method (Figure 92) was completed based on 2 distinct coal types and compared to a sample from the Kubu exploration programme. A range of gas content values were used for each coal type to demonstrate how the ratio will change at different saturation states. The premise is that higher gas content values for a specific coal type at similar depths will indicate higher saturation states. As the Kubu sample had isotherm data available, the gas content at 100% saturation was used to compare with the measured gas content (Figure 92). In cases where the relative saturations throughout the zone remain fairly constant the decision can be made to submit only one sample for isotherm analysis. All samples selected for isotherm testing need to have a full petrography analysis with maceral typing and vitrinite reflectance measurements. Additional petrography samples may be taken for maturity profiling. 149 Figure 91 Isotherm sample selection. 150 Depth Lithology Coal Zonation Description Desorption Clean Coal Minimum Gas Maximum Gas Average Gas Isotherm Samples (m) Samples Taken Thickness from Content (DAF) Content (DAF) Content (DAF) Taken Wireline (m) 200 UPPER Carbonaceous mudstones with thin dull coal MARKER stringers. 2 2.5 35 48 42 1 205 210 215 ZONE 4 Bright coal with interbedded carbonaceous mudstone. Calcite in fractures and cleats. 6 8.9 125 147 137 1 220 225 230 ZONE 3 Dull coal with interbedded carbonaceous mudstone. Abundant pyrite bands. 6 12.1 40 122 89 2 235 240 245 250 ZONE 2 Bright coal with interbedded carbonaceous mudstone towards top and base. 9 10.7 40 156 100 2 255 260 265 270 Upper coal is dull with pyrite bands. Bright 275 coal in towards base. Dark, carbonaceous ZONE 1 mudstone separates the upper and lower 6 8.4 72 99 80 1 coal units. Minor calcite on fractures and cleats. 280 285 LOWER Carbonaceous mudstones with thin dull coal 1 1.1 30 30 30 1 290 MARKER stringers. Frequent pyrite bands Lithology Legend Mudstone Carbonaceous mudstone Siltstone Sandstone Carbonaceous mudstone with coal stringers Coal with interbedded carbonaceous mudstone Dull coal Bright coal Figure 92 Example of desorption and coal data over a heterogeneous sampling zone. 151 6.2.6. Data Reporting When reporting the sampling data in spread sheets it is imperative to quality check all information when adding the information. Adding incorrect data to the master sheet will affect all calculations and models. The best approach is to have a master sheet, to which all data pertaining to a borehole can be added, that can be used for evaluation and modelling. When preparing the master sheet limitations and idiosyncrasies of the preferred modelling package needs to be taken into account as the input methods in various packages may differ vastly. Always be mindful that a number of modelling packages have character limitations. A useful character limit to use in master sheets is twelve (12) characters and to achieve this, a coding system as shown in Table 35 can be used. This coding system allows for the creation of single row spread sheets that can be read by all modelling packages and database managers. The codes can be programmed into the package to recognise the analysis and units for quick reference decreasing the model processing time. Although it may take some time to get fully accustomed with a coding system as proposed, the advantages relating to compatibility across modelling and evaluation platforms will increase processing efficiency. 152 Table 35 Proposed coding library for CBM exploration borehole, sampling and analysis information. 153 7. SUMMARY The growing energy demand coupled with a finite coal supply has resulted in industry leaders identifying and investigating new energy sources for future use. Natural gas is a transitionary fuel during the period where low-carbon alternatives to coal and nuclear are investigated. In North America natural gas is being used extensively as the preferred energy source for domestic use and is one of the cleanest fossil fuels used for electricity generation. Currently two primary types of gas resources, conventional from high permeability reservoirs and unconventional from low permeability reservoirs, are being exploited. The most well-known of the unconventional gasses is Shale Gas that gained notoriety as a result of the completion method known as fraccing. Another unconventional resource, currently being exploited in North America and Australia, is coal bed methane (CBM) where deep coal seams are exploited and gas produced. CBM was the focus of this evaluation. In the United States CBM has been produced commercially since the mid 1970’s when operators started to modify existing petroleum industry technology. CBM is the term used for the natural gas that is sourced by thermogenic alterations of coal or by biogenic action of indigenous microbes on the coal. During the coalification process the decomposition of the organic material produces methane gas which along with other gases, including nitrogen and carbon dioxide, is adsorbed onto the coal. The generation capability of biogenic methane is very difficult to measure or predict, however, biogenic gas generation has been investigated as a reservoir enrichment technique. The saturation state of a coal seam is determined by comparing the measured gas content to the maximum sorptive capacity of the coal. A saturated coal seam will produce gas nearly simultaneous to the initiation of the water pumping, whereas there is a long period of water abstraction required prior to any gas production in under-saturated seams. This reduces the overall production capability of a seam. Southern Africa has very few producing conventional gas fields, mostly off-shore South Africa and Namibia. The vast marine shales of the Main Karoo Basin, in South Africa, and coal fields in Southern Africa have been the focus of these exploration efforts. The most notable programmes are the Waterberg CBM near 154 Lephalale, operated by Anglo Coal and planned Karoo shale gas project, operated by Shell in South Africa. The CBM resources in Botswana and Zimbabwe have for the past two decades been seen as a potentially exploitable gas deposit and potential supplement and in time a substitute for coal as the primary energy source in the region. To date, there has been a great deal of speculation on the size of the potential resource with a wide range of values reported. The values are often based on either proprietary data or single point datasets that have been extrapolated to fit a regional study area. One of the major limitations noted with previous CBM resource evaluations was the lack of compensation for lower saturations. In a number of the previous evaluations reviewed full saturation was presumed as opposed to lower saturation values noted in a number of assessments. Currently there are no commercially producing CBM fields in Southern Africa, however, a number of companies, particularly Tlou in central Botswana and Anglo Coal in the Lephalale region in South Africa, have had some exploration success. The Karoo Supergroup is the primary target for CBM exploration but is poorly exposed in Botswana and only a few outcrop descriptions could be made previously. The stratigraphic descriptions were mainly obtained from limited deep boreholes drilled in the 1970’s aided by a deep resistivity survey. In Zimbabwe there has been a long history of coal mining and the stratigraphic nomenclature was developed from outcrops, drill logs and underground maps. The coal is found in the Permian Ecca Group and can occur as discrete seams in Zimbabwe or thin stringers in Botswana. The coal measures are found throughout the study area but, in north-eastern Botswana only four of the Anglo Coal Botswana boreholes intersected the coal indicating a pinch out of the lower Karoo strata. Coal is ranked based on the constituents, physical properties and thermal maturity as the raw peat is transformed to anthracite. In the Mid-Zambezi Basin an apparent decrease in the coal rank over relatively short distance north-eastwards from Wankie to Sengwa and between Lusulu and Sengwa has been noted. In Botswana, evaluations of the Dukwi coalfield indicated that the coal is of low rank. It was possible to rank the coals within the study area using reported proximate analysis. 155 For the evaluation the ASTM standard of coal rank classification was used as it is relatable to gas holding capacities. In turn, these gas holding capacities were used to evaluate the CBM resource potential of the study area. The calculated coal rank in the area ranged from subbituminous to medium volatile bituminous. Once an evaluation on the production capacity is attempted it is of utmost importance to isolate the primary producing zones and establish the regional continuity and possible compartmentalisation of these. With the sparse data this was not possible nor was it required at the regional scale of the assessment. The nett coal thickness, collected from published literature, was used for the resource assessment. The evaluation of the Shangani Energy and Anglo Coal Botswana data indicate that there is a wide range of saturation levels present. Under-saturated coals have a long period of production where only water will be produced that lengthens the time from production start to delivery of the first commercial gas. This under-saturation combined with lower permeabilities can lead to a very tight well spacing being required and raising the overall capital investment required for full field development. A further influence of under-saturation of the coal is that the estimated gas contents from laboratory testing are skewed and ultimately higher values are assumed. For this evaluation a range of saturation states, based on analogue data, were used to produce more accurate gas content distributions. As a result of sparse field data the datasets required for the resources evaluation were separated into two categories, 1) Measured, datasets which had been obtained from published logs, papers and maps and subsequently modelled to show the regional distribution of the measurements, and 2) Inferred and Calculated datasets not explicitly or widely reported and subsequently interpreted and calculated from available data using previously reported techniques and analogues. Schlumberger GeoX software was used for a probabilistic resource calculation using Monte Carlo simulations with ten thousand iterations. For the evaluation statistically calculated data distribution parameters were used as inputs. Recoverable resource 156 estimations were not conducted as this is highly dependent on data that is not available in the public domain. Statistical distributions of the area, coal thickness, coal density and gas content data were used to determine the input values to the GeoX volumetric calculation. The resource estimation results showed a wide distribution of probable values. This is indicative of a poorly understood region with a great deal of assumption as opposed to good exploration data. The P50 resource value was 22 Tcf. This resource value was compared to major basins in Canada and the United States and found that the resource density (g/cm³) in the study area was significantly lower than the other basins. The major basins in Canada and the US have a significantly higher resource density (g/cm³) than that of the study area indicating a lower prospectivity for CBM. Once more reliable regional data becomes available it will be possible to update this evaluation, however, from previous investigations within the region the general exploration and development potential is low and to date not a single project comparable to the North American basins have been found. The primary challenge during the assessment of the study area was the availability of reliable geological and gas content data. If regional data collection and reporting was standardised it would be possible to assess the area with a greater amount of certainty. Practical guidelines, applicable on future CBM exploration programmes, were developed. These guidelines aim to ensure a uniform quality of data that can be used for regional assessments. 157 8. CONCLUSIONS Even with a resource value of 22Tcf, the major basins in Canada and the US have significantly higher resource densities than that of the Study Area indicating a lower prospectivity for CBM. If saturation and permeability measurements become available for the study area it will be possible to evaluate the production potential and subsequent economic viability. Until such time the study area can be viewed as a stranded resource with no measureable economic value. The CBM exploration industry in Southern Africa is still in its infancy. To date, because of the lack of Southern African standards, companies have placed greater emphasis on budget rather than data quality. The culture of poor data collection and lack of publically available reports increases the difficulty of any evaluation such as this one. Using actual field data rather than the inferred gas contents will have an effect on a resource evaluation. The guidelines developed during this study aim to improve the quality of data collected whilst being appreciative of cost. 158 9. RECOMMENDATIONS Similar future regional evaluations need to be based on reliable, publically available data. This data reliability must be based on acceptable, standardised data collection methods. The Kubu Energy Relinquishment Report for the 2013 Botswana campaign should be seen as the best example for data reporting as the report included all field, laboratory and interpreted datasets in the publically available pack. 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(1982) trend line Equations used in this evaluation. 196 Appendix D List of isotherm samples collected and analysed by Kubu Energy (after Faiz, et al., 2013). 205 Appendix E Gas content values from the Shangani Energy exploration data digitised from the Barker (2006) graph. 207 171 Appendix A Schedule of borehole data, indicating coal depth and thickness used in this study. Sequence Country Area Borehole ID / Field Name Borehole Coal Interval Sample Composite Data Source Total Mid-Point Coal Depth Thickness (m) From (m) To (m) (m) 1 Zimbabwe Western Areas M 53 292.12 284.19 291.57 287.88 7.38 Palloks (1984) 2 Zimbabwe Western Areas M 55 296.31 288.81 294.50 291.66 5.69 Palloks (1984) 3 Zimbabwe Western Areas M 56 257.03 249.09 254.76 251.93 5.67 Palloks (1984) 4 Zimbabwe Western Areas M 57 288.60 281.96 287.22 284.59 5.26 Palloks (1984) 5 Zimbabwe Western Areas M 58 253.24 243.00 252.28 247.64 9.28 Palloks (1984) 6 Zimbabwe Western Areas M 59 296.14 287.10 294.98 291.04 7.88 Palloks (1984) 7 Zimbabwe Western Areas M 60 289.11 279.04 287.36 283.20 8.32 Palloks (1984) 8 Zimbabwe Western Areas M 62 267.16 259.91 266.36 263.14 6.45 Palloks (1984) 9 Zimbabwe Western Areas M 63 260.35 252.67 258.78 255.73 6.11 Palloks (1984) 10 Zimbabwe Western Areas M 64 259.60 251.54 253.60 252.57 2.06 Palloks (1984) 11 Zimbabwe Western Areas M 65 105.14 88.63 103.81 96.22 9.46 Palloks (1984) 12 Zimbabwe Western Areas M 66 49.84 35.19 48.38 41.79 7.39 Palloks (1984) 13 Zimbabwe Western Areas M 67 42.27 24.70 34.33 29.52 3.90 Palloks (1984) 14 Zimbabwe Western Areas M 68 26.08 15.31 24.03 19.67 6.27 Palloks (1984) 15 Zimbabwe Western Areas M 69 112.09 100.61 109.31 104.96 5.72 Palloks (1984) 16 Zimbabwe Western Areas M 70 72.58 55.51 71.32 63.42 8.20 Palloks (1984) 17 Zimbabwe Western Areas M 71 32.79 15.75 31.62 23.69 9.20 Palloks (1984) 18 Zimbabwe Western Areas M 72 132.30 110.65 123.89 117.27 9.65 Palloks (1984) 19 Zimbabwe Western Areas M 73 117.47 99.06 116.83 107.95 8.70 Palloks (1984) 20 Zimbabwe Western Areas M 74 87.28 69.18 85.98 77.58 10.11 Palloks (1984) 21 Zimbabwe Western Areas M 75 53.74 33.00 51.43 42.22 13.91 Palloks (1984) 22 Zimbabwe Western Areas M 76 21.85 14.02 19.75 16.89 5.73 Palloks (1984) 23 Zimbabwe Western Areas M 77 115.68 87.78 113.39 100.59 7.76 Palloks (1984) 24 Zimbabwe Western Areas M 78 87.96 75.73 85.96 80.85 7.53 Palloks (1984) 25 Zimbabwe Western Areas M 79 51.58 36.51 51.28 43.90 8.86 Palloks (1984) 26 Zimbabwe Western Areas M 80 24.30 9.08 22.29 15.69 6.68 Palloks (1984) 27 Zimbabwe Western Areas M 81 108.01 90.86 106.31 98.59 8.27 Palloks (1984) 28 Zimbabwe Western Areas M 82 75.00 62.87 72.99 67.93 5.18 Palloks (1984) 29 Zimbabwe Western Areas M 83 36.13 25.38 34.13 29.76 5.82 Palloks (1984) 30 Zimbabwe Western Areas M 85 100.42 82.58 93.29 87.94 5.13 Palloks (1984) 31 Zimbabwe Western Areas M 86 67.60 56.68 65.15 60.92 3.66 Palloks (1984) 32 Zimbabwe Western Areas M 87 37.07 22.00 35.81 28.91 8.03 Palloks (1984) 33 Zimbabwe Western Areas M 88 9.36 4.20 8.90 6.55 4.70 Palloks (1984) 34 Zimbabwe Western Areas M 89 113.44 94.76 107.99 101.38 4.00 Palloks (1984) 35 Zimbabwe Western Areas M 90 92.90 75.70 86.42 81.06 4.40 Palloks (1984) 36 Zimbabwe Western Areas M 91 65.51 56.00 65.09 60.55 3.02 Palloks (1984) 37 Zimbabwe Western Areas M 92 38.70 20.31 37.26 28.79 9.12 Palloks (1984) 38 Zimbabwe Western Areas M 94 93.70 74.04 83.46 78.75 4.70 Palloks (1984) 39 Zimbabwe Western Areas M 95 58.48 43.11 57.73 50.42 8.74 Palloks (1984) 40 Zimbabwe Western Areas 1740 169.90 156.38 168.90 162.64 12.52 Palloks (1984) 172 Sequence Country Area Borehole ID / Field Name Borehole Coal Interval Sample Composite Data Source Total Mid-Point Coal Depth Thickness (m) From (m) To (m) (m) 41 Zimbabwe Western Areas 1741 188.00 179.20 187.30 183.25 8.10 Palloks (1984) 42 Zimbabwe Western Areas 1742 173.30 164.26 171.90 168.08 7.64 Palloks (1984) 43 Zimbabwe Western Areas 1743 257.50 249.92 256.60 253.26 6.68 Palloks (1984) 44 Zimbabwe Western Areas 1744 265.10 255.48 262.80 259.14 7.32 Palloks (1984) 45 Zimbabwe Western Areas 1745 258.10 251.76 257.70 254.73 5.94 Palloks (1984) 46 Zimbabwe Western Areas 1746 214.00 206.97 213.50 210.24 6.53 Palloks (1984) 47 Zimbabwe Western Areas 1747 302.40 292.29 301.20 296.75 8.91 Palloks (1984) 48 Zimbabwe Western Areas 1748 280.40 271.14 278.20 274.67 7.06 Palloks (1984) 49 Zimbabwe Western Areas 1749 241.30 229.92 239.60 234.76 9.68 Palloks (1984) 50 Zimbabwe Western Areas 1750 289.90 282.29 287.70 285.00 5.41 Palloks (1984) 51 Zimbabwe Western Areas 1751 297.50 285.21 295.80 290.51 10.59 Palloks (1984) 52 Zimbabwe Western Areas 1752 320.60 306.92 318.20 312.56 11.28 Palloks (1984) 53 Zimbabwe Western Areas 1753 0.00 Palloks (1984) 54 Zimbabwe Western Areas 1754 196.20 187.34 196.00 191.67 8.66 Palloks (1984) 55 Zimbabwe Western Areas 1755 281.00 173.98 180.10 177.04 6.12 Palloks (1984) 56 Zimbabwe Western Areas 1756 284.80 274.18 283.30 278.74 9.12 Palloks (1984) 57 Zimbabwe Western Areas 1757 299.40 290.10 296.90 293.50 6.80 Palloks (1984) 58 Zimbabwe Western Areas 1758 336.90 326.76 335.60 331.18 8.84 Palloks (1984) 59 Zimbabwe Western Areas 1759 312.30 302.67 311.30 306.99 8.63 Palloks (1984) 60 Zimbabwe Western Areas 1760 332.60 321.99 332.20 327.10 10.21 Palloks (1984) 61 Zimbabwe Western Areas 1761 308.50 297.95 306.20 302.08 8.25 Palloks (1984) 62 Zimbabwe Western Areas 1763 295.70 0.00 Palloks (1984) 63 Zimbabwe Western Areas 1764A 326.40 313.47 325.47 319.47 11.73 Palloks (1984) 64 Zimbabwe Entuba E 1 280.72 0.00 Palloks (1984) 65 Zimbabwe Entuba E 2 56.46 34.89 47.39 41.14 12.50 Palloks (1984) 66 Zimbabwe Entuba E 3 46.63 33.00 43.38 38.19 10.38 Palloks (1984) 67 Zimbabwe Entuba E 3A 46.33 33.70 44.53 39.12 10.83 Palloks (1984) 68 Zimbabwe Entuba E 4 51.51 35.25 46.18 40.72 10.93 Palloks (1984) 69 Zimbabwe Entuba E 5 63.40 49.68 61.77 55.73 12.09 Palloks (1984) 70 Zimbabwe Entuba E 6 500.50 486.16 497.13 491.65 10.97 Palloks (1984) 71 Zimbabwe Entuba E 6 500.50 486.16 497.13 491.65 10.97 Palloks (1984) 72 Zimbabwe Entuba E 7 570.10 547.62 559.60 553.61 11.98 Palloks (1984) 73 Zimbabwe Entuba E 8 82.90 69.11 80.77 74.94 11.66 Palloks (1984) 74 Zimbabwe Entuba E 8 82.90 69.11 80.77 74.94 11.66 Palloks (1984) 75 Zimbabwe Entuba E 8 82.90 69.11 80.77 74.94 11.66 Palloks (1984) 76 Zimbabwe Entuba E 9 117.50 103.33 115.52 109.43 12.19 Palloks (1984) 77 Zimbabwe Entuba E 9A 62.92 54.86 64.26 59.56 9.40 Palloks (1984) 78 Zimbabwe Entuba E 9A 62.92 54.86 64.26 59.56 9.40 Palloks (1984) 79 Zimbabwe Entuba E 9A 62.92 54.86 64.26 59.56 9.40 Palloks (1984) 80 Zimbabwe Entuba E 10 48.02 34.16 46.33 40.25 12.17 Palloks (1984) 81 Zimbabwe Entuba E 12 61.57 47.72 57.06 52.39 9.34 Palloks (1984) 173 Sequence Country Area Borehole ID / Field Name Borehole Coal Interval Sample Composite Data Source Total Mid-Point Coal Depth Thickness (m) From (m) To (m) (m) 82 Zimbabwe Entuba E 12 61.57 47.72 57.06 52.39 9.34 Palloks (1984) 83 Zimbabwe Entuba E 13 44.50 32.31 40.81 36.56 8.50 Palloks (1984) 84 Zimbabwe Entuba E 15 396.22 346.40 359.66 353.03 13.26 Palloks (1984) 85 Zimbabwe Entuba E 15 396.22 346.40 359.66 353.03 13.26 Palloks (1984) 86 Zimbabwe Entuba E 16A 63.40 49.07 62.00 55.54 12.93 Palloks (1984) 87 Zimbabwe Entuba E 16A 63.40 49.07 62.00 55.54 12.93 Palloks (1984) 88 Zimbabwe Entuba E 16A 63.40 49.07 62.00 55.54 12.93 Palloks (1984) 89 Zimbabwe Entuba E 17 46.63 0.00 Palloks (1984) 90 Zimbabwe Entuba E 17A 60.05 49.53 59.61 54.57 10.08 Palloks (1984) 91 Zimbabwe Entuba E 18 71.02 57.61 70.02 63.82 12.41 Palloks (1984) 92 Zimbabwe Entuba E 18 71.02 57.61 70.02 63.82 12.41 Palloks (1984) 93 Zimbabwe Entuba E 18 71.02 57.61 70.02 63.82 12.41 Palloks (1984) 94 Zimbabwe Entuba E 19 39.77 0.00 Palloks (1984) 95 Zimbabwe Entuba E 19A 45.87 39.01 43.84 41.43 4.83 Palloks (1984) 96 Zimbabwe Entuba E 19B 52.42 39.01 48.87 43.94 9.86 Palloks (1984) 97 Zimbabwe Entuba E 19C 54.56 41.15 53.04 47.10 11.89 Palloks (1984) 98 Zimbabwe Entuba E 19C 54.56 41.15 53.04 47.10 11.89 Palloks (1984) 99 Zimbabwe Entuba E 19C 54.56 41.15 53.04 47.10 11.89 Palloks (1984) 100 Zimbabwe Entuba E 20 55.83 0.00 Palloks (1984) 101 Zimbabwe Entuba E 21 183.49 171.00 181.98 176.49 10.98 Palloks (1984) 102 Zimbabwe Entuba E 22 45.24 0.00 Palloks (1984) 103 Zimbabwe Entuba E 24 68.05 55.44 65.84 60.64 10.40 Palloks (1984) 104 Zimbabwe Entuba E 24 68.05 55.44 65.84 60.64 10.40 Palloks (1984) 105 Zimbabwe Entuba E 25 87.13 55.91 67.57 61.74 11.66 Palloks (1984) 106 Zimbabwe Entuba E 26 109.28 94.14 104.10 99.12 9.87 Palloks (1984) 107 Zimbabwe Entuba E 27 281.64 270.05 281.18 275.62 11.13 Palloks (1984) 108 Zimbabwe Entuba E 28 29.56 0.00 Palloks (1984) 109 Zimbabwe Entuba E 29 116.13 100.58 114.66 107.62 14.08 Palloks (1984) 110 Zimbabwe Entuba E 29 116.13 100.58 114.66 107.62 14.08 Palloks (1984) 111 Zimbabwe Entuba E 30 63.40 53.34 61.57 57.46 8.23 Palloks (1984) 112 Zimbabwe Entuba E 30 63.40 53.34 61.57 57.46 8.23 Palloks (1984) 113 Zimbabwe Entuba E 31 170.99 161.39 170.38 165.89 8.99 Palloks (1984) 114 Zimbabwe Entuba E 32 115.21 105.77 114.60 110.19 8.83 Palloks (1984) 115 Zimbabwe Entuba E 32 115.21 105.77 114.60 110.19 8.83 Palloks (1984) 116 Zimbabwe Entuba E 33 101.19 89.97 100.35 95.16 10.38 Palloks (1984) 117 Zimbabwe Entuba E 33 101.19 89.97 100.35 95.16 10.38 Palloks (1984) 118 Zimbabwe Entuba E 34 174.04 161.08 173.35 167.22 12.27 Palloks (1984) 119 Zimbabwe Entuba E 34 174.04 161.08 173.35 167.22 12.27 Palloks (1984) 120 Zimbabwe Entuba E 34 174.04 161.08 173.35 167.22 12.27 Palloks (1984) 121 Zimbabwe Entuba E 35 181.05 170.69 180.74 175.72 10.05 Palloks (1984) 122 Zimbabwe Entuba E 36 215.18 204.08 212.58 208.33 8.50 Palloks (1984) 174 Sequence Country Area Borehole ID / Field Name Borehole Coal Interval Sample Composite Data Source Total Mid-Point Coal Depth Thickness (m) From (m) To (m) (m) 123 Zimbabwe Entuba E 37 266.69 256.64 265.18 260.91 8.54 Palloks (1984) 124 Zimbabwe Entuba E 38 336.76 329.79 332.38 331.09 2.59 Palloks (1984) 125 Zimbabwe Entuba E 39 67.06 53.04 66.55 59.80 13.51 Palloks (1984) 126 Zimbabwe Entuba E 40 51.26 37.80 50.90 44.35 13.10 Palloks (1984) 127 Zimbabwe Entuba E 41 56.43 43.93 55.93 49.93 12.00 Palloks (1984) 128 Zimbabwe Entuba E 42 64.92 52.58 64.58 58.58 12.00 Palloks (1984) 129 Zimbabwe Entuba E 43 67.56 55.56 67.56 61.56 12.00 Palloks (1984) 130 Zimbabwe Entuba E 44 54.86 49.99 53.77 51.88 3.78 Palloks (1984) 131 Zimbabwe Entuba E 45 21.34 8.53 20.37 14.45 11.84 Palloks (1984) 132 Zimbabwe Entuba E 46 48.92 31.23 41.80 36.52 10.57 Palloks (1984) 133 Zimbabwe Entuba E 47 48.92 37.19 48.52 42.86 11.33 Palloks (1984) 134 Zimbabwe Entuba E 48 57.00 42.98 56.69 49.84 13.71 Palloks (1984) 135 Zimbabwe Entuba E 49 61.57 50.90 60.86 55.88 9.96 Palloks (1984) 136 Zimbabwe Entuba E 50 63.40 49.02 61.23 55.13 12.21 Palloks (1984) 137 Zimbabwe Entuba E 51 48.16 33.51 46.80 40.16 13.29 Palloks (1984) 138 Zimbabwe Entuba E 52 60.00 45.09 59.21 52.15 14.12 Palloks (1984) 139 Zimbabwe Entuba E 53 55.00 42.67 52.88 47.78 10.21 Palloks (1984) 140 Zimbabwe Entuba E 54 94.79 81.08 92.81 86.95 11.73 Palloks (1984) 141 Zimbabwe Entuba E 55 116.13 102.11 115.66 108.89 13.55 Palloks (1984) 142 Zimbabwe Entuba E 56 53.03 39.93 51.77 45.85 11.84 Palloks (1984) 143 Zimbabwe Entuba E 57 150.00 137.33 147.68 142.51 10.35 Palloks (1984) 144 Zimbabwe Entuba E 58 173.02 160.43 172.73 166.58 12.30 Palloks (1984) 145 Zimbabwe Entuba E 59 52.73 35.29 51.06 43.18 15.77 Palloks (1984) 146 Zimbabwe Entuba E 60 201.00 188.06 199.17 193.62 11.11 Palloks (1984) 147 Zimbabwe Entuba E 61 201.83 185.17 200.67 192.92 15.50 Palloks (1984) 148 Zimbabwe Entuba E 62 62.79 46.35 61.73 54.04 15.38 Palloks (1984) 149 Zimbabwe Entuba E 63 224.33 210.64 222.73 216.69 12.09 Palloks (1984) 150 Zimbabwe Entuba E 64 230.42 210.08 230.42 220.25 20.34 Palloks (1984) 151 Zimbabwe Entuba E 65 100.00 89.81 99.16 94.49 9.98 Palloks (1984) 152 Zimbabwe Entuba E 66 108.20 94.67 106.96 100.82 12.29 Palloks (1984) 153 Zimbabwe Entuba E 66A 106.71 94.59 105.73 100.16 11.14 Palloks (1984) 154 Zimbabwe Entuba E 67 90.83 76.88 89.99 83.44 13.11 Palloks (1984) 155 Zimbabwe Entuba E 68 91.44 74.19 87.99 81.09 13.80 Palloks (1984) 156 Zimbabwe Entuba E 69 153.64 140.85 153.54 147.20 12.69 Palloks (1984) 157 Zimbabwe Entuba E 70 161.00 150.27 160.67 155.47 10.40 Palloks (1984) 158 Zimbabwe Entuba E 71 162.00 151.91 161.46 156.69 9.55 Palloks (1984) 159 Zimbabwe Entuba E 72 154.00 144.13 152.90 148.52 8.77 Palloks (1984) 160 Zimbabwe Entuba E 73 215.63 203.05 214.63 208.84 11.58 Palloks (1984) 161 Zimbabwe Entuba E 74 195.73 183.99 194.54 189.27 10.55 Palloks (1984) 162 Zimbabwe Entuba E 75 198.73 189.20 197.66 193.43 8.46 Palloks (1984) 163 Zimbabwe Entuba E 76 180.74 176.02 180.12 178.07 4.10 Palloks (1984) 175 Sequence Country Area Borehole ID / Field Name Borehole Coal Interval Sample Composite Data Source Total Mid-Point Coal Depth Thickness (m) From (m) To (m) (m) 164 Zimbabwe Entuba E 77 256.00 243.75 254.66 249.21 10.91 Palloks (1984) 165 Zimbabwe Entuba E 78 238.00 226.49 237.38 231.94 10.89 Palloks (1984) 166 Zimbabwe Entuba E 79 236.28 226.10 235.93 231.02 9.83 Palloks (1984) 167 Zimbabwe Entuba E 80B 256.30 246.14 255.40 250.77 9.26 Palloks (1984) 168 Zimbabwe Entuba E 81 249.85 241.28 249.18 245.23 7.82 Palloks (1984) 169 Zimbabwe Entuba E 82 333.99 325.23 333.69 329.46 8.46 Palloks (1984) 170 Zimbabwe Entuba E 83 323.48 314.62 323.22 318.92 8.60 Palloks (1984) 171 Zimbabwe Entuba E 84 269.82 261.14 269.66 265.40 8.52 Palloks (1984) 172 Zimbabwe Entuba E 85 323.86 315.49 323.26 319.38 7.77 Palloks (1984) 173 Zimbabwe Entuba E 87 12.75 6.08 10.50 8.29 4.42 Palloks (1984) 174 Zimbabwe Entuba E 88 63.94 53.54 63.85 58.70 10.31 Palloks (1984) 175 Zimbabwe Entuba E 89 54.04 48.46 52.94 50.70 4.48 Palloks (1984) 176 Zimbabwe Entuba E 90 50.10 38.60 48.87 43.74 10.27 Palloks (1984) 177 Zimbabwe Entuba E 91 63.80 49.38 61.10 55.24 11.72 Palloks (1984) 178 Zimbabwe Entuba E 92 59.10 47.50 59.08 53.29 11.58 Palloks (1984) 179 Zimbabwe Entuba E 93 77.61 64.22 64.22 Palloks (1984) 180 Zimbabwe Entuba E 94 70.91 58.92 69.31 64.12 10.39 Palloks (1984) 181 Zimbabwe Entuba E 96 212.23 0.00 Palloks (1984) 182 Zimbabwe Entuba E 97 272.59 0.00 Palloks (1984) 183 Zimbabwe Entuba E 98 122.12 110.50 121.60 116.05 11.10 Palloks (1984) 184 Zimbabwe Entuba E 99 227.61 218.85 227.13 222.99 8.28 Palloks (1984) 185 Zimbabwe Entuba E 101 240.24 229.08 238.44 233.76 9.36 Palloks (1984) 186 Zimbabwe Entuba E 102 211.65 201.80 210.60 206.20 8.80 Palloks (1984) 187 Zimbabwe Entuba E 103 102.54 93.46 101.82 97.64 8.36 Palloks (1984) 188 Zimbabwe Entuba E 104 129.85 119.41 125.83 122.62 6.42 Palloks (1984) 189 Zimbabwe Lubu LBW 1 172.52 11.12 13.14 12.13 2.02 Palloks (1984) 190 Zimbabwe Lubu LBW 1 172.52 16.17 20.23 18.20 3.73 Palloks (1984) 191 Zimbabwe Lubu LBW 1 172.52 28.82 43.33 36.08 Palloks (1984) 192 Zimbabwe Lubu LBW 1 172.52 0.00 10.53 Palloks (1984) 193 Zimbabwe Lubu LBW 2 241.86 84.71 88.66 86.69 2.80 Palloks (1984) 194 Zimbabwe Lubu LBW 2 241.86 95.94 111.56 103.75 Palloks (1984) 195 Zimbabwe Lubu LBW 2 241.86 0.00 13.57 Palloks (1984) 196 Zimbabwe Lubu LBW 4 98.98 41.51 43.51 42.51 2.00 Palloks (1984) 197 Zimbabwe Lubu LBW 4 98.98 51.90 70.13 61.02 17.92 Palloks (1984) 198 Zimbabwe Lubu LBW 5 76.81 32.76 36.41 34.59 3.26 Palloks (1984) 199 Zimbabwe Lubu LBW 5 76.81 40.53 56.83 48.68 16.20 Palloks (1984) 200 Zimbabwe Lubu LBW 6 126.64 65.61 74.10 69.86 9.09 Palloks (1984) 201 Zimbabwe Lubu LBW 6 126.64 15.00 98.00 56.50 7.96 Palloks (1984) 202 Zimbabwe Lubu LBW 6 126.64 83.56 92.70 88.13 8.65 Palloks (1984) 203 Zimbabwe Lubu LBW 7 107.08 55.05 58.99 57.02 3.69 Palloks (1984) 204 Zimbabwe Lubu LBW 7 107.08 64.65 82.28 73.47 15.68 Palloks (1984) 176 Sequence Country Area Borehole ID / Field Name Borehole Coal Interval Sample Composite Data Source Total Mid-Point Coal Depth Thickness (m) From (m) To (m) (m) 205 Zimbabwe Lubu LBW 8 78.94 25.64 29.43 27.54 3.43 Palloks (1984) 206 Zimbabwe Lubu LBW 8 78.94 34.90 46.35 40.63 9.31 Palloks (1984) 207 Zimbabwe Lubu LBW 9 73.93 14.81 16.81 15.81 1.91 Palloks (1984) 208 Zimbabwe Lubu LBW 9 73.93 26.60 34.58 30.59 7.98 Palloks (1984) 209 Zimbabwe Lubu LBW 10 99.54 63.13 67.19 65.16 3.74 Palloks (1984) 210 Zimbabwe Lubu LBW 10 99.54 73.22 84.30 78.76 10.98 Palloks (1984) 211 Zimbabwe Lubu LBW 11 64.10 32.11 36.16 34.14 1.70 Palloks (1984) 212 Zimbabwe Lubu LBW 11 64.10 44.04 57.16 50.60 13.12 Palloks (1984) 213 Zimbabwe Lubu LBW 11 64.10 0.00 12.30 Palloks (1984) 214 Zimbabwe Lubu LBW 12 93.49 39.86 50.87 45.37 6.13 Palloks (1984) 215 Zimbabwe Lubu LBW 12 93.49 66.30 79.84 73.07 12.57 Palloks (1984) 216 Zimbabwe Lubu LBW 13 151.05 97.77 102.00 99.89 4.04 Palloks (1984) 217 Zimbabwe Sengwa South S 1 115.83 96.01 113.08 104.55 17.07 Palloks (1984) 218 Zimbabwe Sengwa South S 2 80.47 63.93 77.62 70.78 13.69 Palloks (1984) 219 Zimbabwe Sengwa South S 3 18.59 6.10 15.24 10.67 9.14 Palloks (1984) 220 Zimbabwe Sengwa South S 5 110.03 90.22 107.29 98.76 17.07 Palloks (1984) 221 Zimbabwe Sengwa South S 18 166.12 151.79 160.55 156.17 8.76 Palloks (1984) 222 Zimbabwe Sengwa South S 25 165.19 147.51 159.40 153.46 11.89 Palloks (1984) 223 Zimbabwe Sengwa South S 26 25.60 11.27 21.96 16.62 10.69 Palloks (1984) 224 Zimbabwe Sengwa South S 27 100.28 85.80 97.92 91.86 12.12 Palloks (1984) 225 Zimbabwe Sengwa South S 29 85.04 70.71 80.95 75.83 10.24 Palloks (1984) 226 Zimbabwe Sengwa South S 30 53.95 40.46 49.48 44.97 9.02 Palloks (1984) 227 Zimbabwe Sengwa North M 1 94.49 78.59 90.53 84.56 11.94 Palloks (1984) 228 Zimbabwe Sengwa North M 2 128.82 96.32 111.51 103.92 15.19 Palloks (1984) 229 Zimbabwe Sengwa North M 3 97.83 78.93 93.26 86.10 14.33 Palloks (1984) 230 Zimbabwe Sengwa North M 4 152.69 135.62 145.00 140.31 9.38 Palloks (1984) 231 Zimbabwe Sengwa North M 5 82.90 69.18 78.84 74.01 9.66 Palloks (1984) 232 Zimbabwe Sengwa North M 6 82.90 71.11 78.93 75.02 7.82 Palloks (1984) 233 Zimbabwe Sengwa North M 7 123.13 108.35 118.56 113.46 10.21 Palloks (1984) 234 Zimbabwe Sengwa North M 8 86.86 71.85 83.28 77.57 11.43 Palloks (1984) 235 Zimbabwe Sengwa North M 9 76.19 21.18 34.51 27.85 13.33 Palloks (1984) 236 Zimbabwe Sengwa North M 10 14.62 0.10 11.07 5.59 11.07 Palloks (1984) 237 Zimbabwe Sengwa North M 11 42.66 25.75 38.63 32.19 12.88 Palloks (1984) 238 Zimbabwe Lusulu L 256 (Type Borehole - Main 15.00 190.00 102.50 9.17& A Seams) Palloks (1984) 239 Zimbabwe Lusulu L 252 (Type Borehole - Main 22.50 197.50 110.00 6.15Seam)* Palloks (1984) 240 Zimbabwe Lusulu L 198 (Type Borehole - 26.60 97.77 62.19 4.15Lower & Middle Seam)* Palloks (1984) 241 Zimbabwe Wankie Shallow (Average) 60.00 100.00 80.00 9.00 Mapani et al. (2013); Palloks (1984); Cairncross (2001) and Moyo (2012) 242 Zimbabwe Wankie Deep(Average) 200.00 700.00 450.00 9.00 Bakker (2006) 243 Zimbabwe Gokwe Gokwe Average 200.00 300.00 250.00 9.00 Oesterlen & Lepper (2005) and Padcoal (Pvt) Ltd 177 Sequence Country Area Borehole ID / Field Name Borehole Coal Interval Sample Composite Data Source Total Mid-Point Coal Depth Thickness (m) From (m) To (m) (m) (2011) 244 Botswana Northeast Botswana N1/1 45.10 46.70 45.90 1.00 Smith (1984) 245 Botswana Northeast Botswana N1/2 41.00 89.00 65.00 5.50 Smith (1984) 246 Botswana Northeast Botswana N1/3 24.00 91.00 57.50 7.73 Smith (1984) 247 Botswana Northeast Botswana N2/1 52.70 118.10 85.40 19.60 Smith (1984) 248 Botswana Northeast Botswana N3/1 38.30 119.00 78.65 23.65 Smith (1984) 249 Botswana Northeast Botswana N4/1 113.30 189.00 151.15 14.03 Smith (1984) 250 Botswana Northeast Botswana N5/2 5.00 41.70 23.35 6.80 Smith (1984) 251 Botswana Northeast Botswana N5/1 10.40 41.20 25.80 4.10 Smith (1984) 252 Botswana Northeast Botswana N6/1 14.70 70.50 42.60 2.50 Smith (1984) 253 Botswana Northeast Botswana N8/2 75.35 124.50 99.93 11.50 Smith (1984) 254 Botswana Northeast Botswana N12/1 79.90 150.85 115.38 12.50 Smith (1984) 255 Botswana Northeast Botswana N9/1 75.40 124.60 100.00 8.74 Smith (1984) 256 Botswana Northeast Botswana N10/1 89.40 177.30 133.35 21.76 Smith (1984) 257 Botswana Northeast Botswana N11/3 110.60 153.50 132.05 8.15 Smith (1984) 258 Botswana Northeast Botswana N7/1 0.00 Smith (1984) 259 Botswana Northeast Botswana N7/2 0.00 Smith (1984) 260 Botswana Northeast Botswana N7/3 0.00 Smith (1984) 261 Botswana Northeast Botswana N8/1 0.00 Smith (1984) 262 Botswana Northeast Botswana N8/2 0.00 Smith (1984) 263 Botswana Northeast Botswana N12/1 0.00 Smith (1984) 264 Botswana Northeast Botswana N9/1 0.00 Smith (1984) 265 Botswana Northeast Botswana N10/1 0.00 Smith (1984) 266 Botswana Northeast Botswana N11/3 0.00 Smith (1984) 267 Botswana Northeast Botswana N11/2 0.00 Smith (1984) 268 Botswana Northeast Botswana N11/1 0.00 Smith (1984) 269 Botswana Northeast Botswana N12/1 0.00 Smith (1984) 270 Botswana Northeast Botswana N12/2 0.00 Smith (1984) 271 Botswana Northeast Botswana N12/3 0.00 Smith (1984) 272 Botswana Northeast Botswana Y1-01 595.00 499.74 566.30 533.02 10.65 Anglo Coal Botswana (2010) 273 Botswana Northeast Botswana Y1-02 769.00 705.54 737.14 721.34 1.29 Anglo Coal Botswana (2010) 274 Botswana Northeast Botswana Y1-03 808.00 705.73 792.74 749.24 16.75 Anglo Coal Botswana (2010) 275 Botswana Northeast Botswana Y1-04 638.18 587.20 605.50 596.35 2.85 Anglo Coal Botswana (2010) 276 Botswana Northeast Botswana PDM006C 701.34 0.00 Anglo Coal Botswana (2010) 277 Botswana Northeast Botswana PDM007A 287.00 0.00 Anglo Coal Botswana (2010) 278 Botswana Northeast Botswana PDM008 663.00 0.00 Anglo Coal Botswana (2010) 279 Botswana Northeast Botswana PDM009 526.00 0.00 Anglo Coal Botswana (2010) 280 Botswana Northeast Botswana PDM011 633.39 0.00 Anglo Coal Botswana (2010) 281 Botswana Northeast Botswana PDM014A 434.00 0.00 Anglo Coal Botswana (2010) 282 Botswana Northeast Botswana PDM015 396.00 0.00 Anglo Coal Botswana (2010) 283 Zimbabwe Lubimbi Lubimbi 11.80 190.00 100.90 Thompson (1981) and Oesterlen & Lepper (2005) 178 Sequence Country Area Borehole ID / Field Name Borehole Coal Interval Sample Composite Data Source Total Mid-Point Coal Depth Thickness (m) From (m) To (m) (m) 284 Zimbabwe Busi Busi 60.00 80.00 70.00 10.00 Oesterlen & Lepper (2005) 285 Zimbabwe Tjolotjo, Sawmills, and Insuza Tjolotjo, Sawmills, and 270.00 330.00 300.00 5.00Insuza Oesterlen & Lepper (2005) 179 Appendix B Schedule of borehole data, indicating coal quality and coal rank estimated from the ash-free fixed carbon, volatile matter and moisture values used in this evaluation. Sample Coal Quality Information Coal Rank based on Ash-Coal Interval Mid-Point Free Fixed Carbon, Volatile Ash-Free Matter and Moisture Values Borehole ID / Field Name Analysis Code From (m) To (m) (m) Comments Long Text Samples 1 M 53 284.19 291.57 287.88 7.38 53.4 1.1 8.0 25.2 65.7 Washed at 1.4 1.2 27.4 71.4 Medium Volatile Bituminous MVB g/cm³ Samples 2 M 55 288.81 294.5 291.655 5.69 53.2 1.1 8.1 24.0 66.8 Washed at 1.4 1.2 26.1 72.7 Medium Volatile Bituminous MVB g/cm³ Samples 3 M 56 249.09 254.76 251.925 5.67 57.9 1.2 8.2 23.3 67.3 Washed at 1.4 1.3 25.4 73.3 Medium Volatile Bituminous MVB g/cm³ Samples 4 M 57 281.96 287.22 284.59 5.26 45.2 1.0 9.0 26.4 63.6 Washed at 1.4 1.1 29.0 69.9 Medium Volatile Bituminous MVB g/cm³ Samples 5 M 58 243 252.28 247.64 9.28 78.9 1.1 7.6 25.3 66.0 Washed at 1.4 1.2 27.4 71.4 Medium Volatile Bituminous MVB g/cm³ Samples 6 M 59 287.1 294.98 291.04 7.88 84.5 1.0 6.6 26.3 66.1 Washed at 1.4 1.1 28.2 70.8 Medium Volatile Bituminous MVB g/cm³ Samples 7 M 60 279.04 287.36 283.2 8.32 83.1 1.2 6.7 26.2 65.9 Washed at 1.4 1.3 28.1 70.6 Medium Volatile Bituminous MVB g/cm³ Samples 8 M 62 259.91 266.36 263.135 6.45 65.3 1.2 9.1 27.1 62.6 Washed at 1.4 1.3 29.8 68.9 High Volatile Bituminous - A HVB-A g/cm³ Samples 9 M 63 252.67 258.78 255.725 6.11 75.8 1.2 8.9 29.8 60.1 Washed at 1.4 1.3 32.7 66.0 High Volatile Bituminous - A HVB-A g/cm³ Samples 10 M 64 251.54 253.6 252.57 2.06 1.0 15.3 21.5 62.2 Washed at 1.4 1.2 25.4 73.4 Medium Volatile Bituminous MVB g/cm³ Samples 11 M 65 88.63 103.81 96.22 9.46 43.2 1.1 9.8 32.6 56.5 Washed at 1.4 1.2 36.1 62.6 High Volatile Bituminous - A HVB-A g/cm³ Samples 12 M 66 35.19 48.38 41.785 7.39 35.0 1.2 9.2 33.4 56.2 Washed at 1.4 1.3 36.8 61.9 High Volatile Bituminous - B HVB-B g/cm³ Samples 13 M 67 24.7 34.33 29.515 3.9 51.0 1.3 9.2 33.7 55.8 Washed at 1.4 1.4 37.1 61.5 High Volatile Bituminous - B HVB-B g/cm³ Samples 14 M 68 15.31 24.03 19.67 6.27 1.6 22.7 17.9 57.8 Washed at 1.4 2.1 23.2 74.8 Medium Volatile Bituminous MVB g/cm³ Samples 15 M 69 100.61 109.31 104.96 5.72 47.6 1.3 8.1 33.6 57.0 Washed at 1.4 1.4 36.6 62.0 High Volatile Bituminous - A HVB-A g/cm³ Samples 16 M 70 55.51 71.32 63.415 8.2 30.7 1.2 10.0 32.4 56.4 Washed at 1.4 1.3 36.0 62.7 High Volatile Bituminous - A HVB-A g/cm³ 17 M 71 15.75 31.62 23.685 9.2 28.3 1.4 10.2 32.1 56.3 Samples Washed at 1.4 1.6 35.7 62.7 High Volatile Bituminous - A HVB-A 180 S e q u e n c e C o m p o s i t e C o a l T h i c k n e s s ( m ) Y i e l d ( % ) M o i s t u r e ( % ) A s h ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) M o i s t u r e ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) Coal Quality Information Coal Rank based on Ash- Coal Interval Sample Mid-Point Free Fixed Carbon, Volatile Ash-Free Matter and Moisture Values Borehole ID / Field Name Analysis Code From (m) To (m) (m) Comments Long Text g/cm³ Samples 18 M 72 110.65 123.89 117.27 9.65 37.3 1.1 9.9 31.9 57.1 Washed at 1.4 1.2 35.4 63.4 High Volatile Bituminous - A HVB-A g/cm³ Samples 19 M 73 99.06 116.83 107.945 8.7 40.0 1.4 10.4 31.9 56.3 Washed at 1.4 1.6 35.6 62.8 High Volatile Bituminous - A HVB-A g/cm³ Samples 20 M 74 69.18 85.98 77.58 10.11 38.3 1.5 10.3 31.2 57.0 Washed at 1.4 1.7 34.8 63.5 High Volatile Bituminous - A HVB-A g/cm³ Samples 21 M 75 33 51.43 42.215 13.91 49.7 1.8 9.8 31.4 57.0 Washed at 1.4 2.0 34.8 63.2 High Volatile Bituminous - A HVB-A g/cm³ Samples 22 M 76 14.02 19.75 16.885 5.73 1.6 22.7 17.9 57.8 Washed at 1.4 2.1 23.2 74.8 Medium Volatile Bituminous MVB g/cm³ Samples 23 M 77 87.78 113.39 100.585 7.76 54.7 1.5 9.7 31.4 57.4 Washed at 1.4 1.7 34.8 63.6 High Volatile Bituminous - A HVB-A g/cm³ Samples 24 M 78 75.73 85.96 80.845 7.53 1.6 22.7 17.9 57.8 Washed at 1.4 2.1 23.2 74.8 Medium Volatile Bituminous MVB g/cm³ Samples 25 M 79 36.51 51.28 43.895 8.86 45.7 1.7 9.8 31.3 57.2 Washed at 1.4 1.9 34.7 63.4 High Volatile Bituminous - A HVB-A g/cm³ Samples 26 M 80 9.08 22.29 15.685 6.68 72.1 2.3 8.4 31.0 58.3 Washed at 1.4 2.5 33.8 63.6 High Volatile Bituminous - A HVB-A g/cm³ Samples 27 M 81 90.86 106.31 98.585 8.27 34.6 1.7 10.5 30.8 57.0 Washed at 1.4 1.9 34.4 63.7 High Volatile Bituminous - A HVB-A g/cm³ Samples 28 M 82 62.87 72.99 67.93 5.18 39.2 1.5 9.5 30.6 58.4 Washed at 1.4 1.7 33.8 64.5 High Volatile Bituminous - A HVB-A g/cm³ Samples 29 M 83 25.38 34.13 29.755 5.82 41.6 1.7 9.4 30.7 58.2 Washed at 1.4 1.9 33.9 64.2 High Volatile Bituminous - A HVB-A g/cm³ Samples 30 M 85 82.58 93.29 87.935 5.13 39.7 1.8 11.3 30.9 56.0 Washed at 1.4 2.0 34.8 63.1 High Volatile Bituminous - A HVB-A g/cm³ Samples 31 M 86 56.68 65.15 60.915 3.66 36.4 1.7 10.9 30.4 57.0 Washed at 1.4 1.9 34.1 64.0 High Volatile Bituminous - A HVB-A g/cm³ Samples 32 M 87 22 35.81 28.905 8.03 66.6 2.0 8.8 31.1 58.1 Washed at 1.4 2.2 34.1 63.7 High Volatile Bituminous - A HVB-A g/cm³ Samples 33 M 88 4.2 8.9 6.55 4.7 1.6 22.7 17.9 57.8 Washed at 1.4 2.1 23.2 74.8 Medium Volatile Bituminous MVB g/cm³ 181 S e q u e n c e C o m p o s i t e C o a l T h i c k n e s s ( m ) Y i e l d ( % ) M o i s t u r e ( % ) A s h ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) M o i s t u r e ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) Coal Quality Information Coal Rank based on Ash- Coal Interval Sample Mid-Point Free Fixed Carbon, Volatile Ash-Free Matter and Moisture Values Borehole ID / Field Name Analysis Code From (m) To (m) (m) Comments Long Text Samples 34 M 89 94.76 107.99 101.375 4 47.6 2.3 8.9 30.7 58.1 Washed at 1.4 2.5 33.7 63.8 High Volatile Bituminous - A HVB-A g/cm³ Samples 35 M 90 75.7 86.42 81.06 4.4 47.6 2.0 8.1 31.6 58.3 Washed at 1.4 2.2 34.4 63.4 High Volatile Bituminous - A HVB-A g/cm³ Samples 36 M 91 56 65.09 60.545 3.02 68.2 1.8 10.5 30.8 56.9 Washed at 1.4 2.0 34.4 63.6 High Volatile Bituminous - A HVB-A g/cm³ Samples 37 M 92 20.31 37.26 28.785 9.12 45.0 2.0 9.0 31.4 57.6 Washed at 1.4 2.2 34.5 63.3 High Volatile Bituminous - A HVB-A g/cm³ Samples 38 M 94 74.04 83.46 78.75 4.7 42.3 1.8 10.2 31.0 57.0 Washed at 1.4 2.0 34.5 63.5 High Volatile Bituminous - A HVB-A g/cm³ Samples 39 M 95 43.11 57.73 50.42 8.74 38.5 1.9 10.4 31.1 56.6 Washed at 1.4 2.1 34.7 63.2 High Volatile Bituminous - A HVB-A g/cm³ Samples 40 1740 156.38 168.9 162.64 12.52 1.4 17.5 21.0 60.1 Washed at 1.6 1.7 25.5 72.8 Medium Volatile Bituminous MVB g/cm³ Samples 41 1741 179.2 187.3 183.25 8.1 1.4 20.2 21.0 57.4 Washed at 1.6 1.8 26.3 71.9 Medium Volatile Bituminous MVB g/cm³ Samples 42 1742 164.26 171.9 168.08 7.64 1.7 23.3 21.3 53.7 Washed at 1.6 2.2 27.8 70.0 Medium Volatile Bituminous MVB g/cm³ Samples 43 1743 249.92 256.6 253.26 6.68 1.5 16.2 21.3 61.0 Washed at 1.6 1.8 25.4 72.8 Medium Volatile Bituminous MVB g/cm³ Samples 44 1744 255.48 262.8 259.14 7.32 1.0 15.3 21.5 62.2 Washed at 1.6 1.2 25.4 73.4 Medium Volatile Bituminous MVB g/cm³ Samples 45 1745 251.76 257.7 254.73 5.94 1.0 15.3 21.5 62.2 Washed at 1.6 1.2 25.4 73.4 Medium Volatile Bituminous MVB g/cm³ Samples 46 1746 206.97 213.5 210.235 6.53 1.3 23.7 19.7 55.3 Washed at 1.6 1.7 25.8 72.5 Medium Volatile Bituminous MVB g/cm³ Samples 47 1747 292.29 301.2 296.745 8.91 1.7 12.8 23.0 62.5 Washed at 1.6 1.9 26.4 71.7 Medium Volatile Bituminous MVB g/cm³ Samples 48 1748 271.14 278.2 274.67 7.06 2.0 13.5 22.9 61.6 Washed at 1.6 2.3 26.5 71.2 Medium Volatile Bituminous MVB g/cm³ Samples 49 1749 229.92 239.6 234.76 9.68 1.0 15.3 21.5 62.2 Washed at 1.6 1.2 25.4 73.4 Medium Volatile Bituminous MVB g/cm³ Samples 50 1750 282.29 287.7 284.995 5.41 1.1 20.0 20.1 58.8 Washed at 1.6 1.4 25.1 73.5 Medium Volatile Bituminous MVB g/cm³ 182 S e q u e n c e C o m p o s i t e C o a l T h i c k n e s s ( m ) Y i e l d ( % ) M o i s t u r e ( % ) A s h ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) M o i s t u r e ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) Coal Interval Sample Coal Quality Information Coal Rank based on Ash- Mid-Point Free Fixed Carbon, Volatile Ash-Free Matter and Moisture Values Borehole ID / Field Name Analysis Code From (m) To (m) (m) Comments Long Text Samples 51 1751 285.21 295.8 290.505 10.59 1.8 13.7 23.6 60.9 Washed at 1.6 2.1 27.3 70.6 Medium Volatile Bituminous MVB g/cm³ Samples 52 1752 306.92 318.2 312.56 11.28 1.0 15.3 21.5 62.2 Washed at 1.6 1.2 25.4 73.4 Medium Volatile Bituminous MVB g/cm³ Samples 53 1753 0 1.6 22.7 17.9 57.8 Washed at 1.6 2.1 23.2 74.8 Medium Volatile Bituminous MVB g/cm³ Samples 54 1754 187.34 196 191.67 8.66 1.0 15.3 21.5 62.2 Washed at 1.6 1.2 25.4 73.4 Medium Volatile Bituminous MVB g/cm³ Samples 55 1755 173.98 180.1 177.04 6.12 1.3 19.6 20.5 58.6 Washed at 1.6 1.6 25.5 72.9 Medium Volatile Bituminous MVB g/cm³ Samples 56 1756 274.18 283.3 278.74 9.12 1.0 15.3 21.5 62.2 Washed at 1.6 1.2 25.4 73.4 Medium Volatile Bituminous MVB g/cm³ Samples 57 1757 290.1 296.9 293.5 6.8 1.8 19.6 21.1 57.5 Washed at 1.6 2.2 26.2 71.5 Medium Volatile Bituminous MVB g/cm³ Samples 58 1758 326.76 335.6 331.18 8.84 1.3 12.2 23.6 62.9 Washed at 1.6 1.5 26.9 71.6 Medium Volatile Bituminous MVB g/cm³ Samples 59 1759 302.67 311.3 306.985 8.63 1.3 12.8 24.0 61.9 Washed at 1.6 1.5 27.5 71.0 Medium Volatile Bituminous MVB g/cm³ Samples 60 1760 321.99 332.2 327.095 10.21 1.2 14.1 21.9 62.8 Washed at 1.6 1.4 25.5 73.1 Medium Volatile Bituminous MVB g/cm³ Samples 61 1761 297.95 306.2 302.075 8.25 1.2 15.1 21.4 62.3 Washed at 1.6 1.4 25.2 73.4 Medium Volatile Bituminous MVB g/cm³ Samples 62 1763 0 1.6 22.7 17.9 57.8 Washed at 1.6 2.1 23.2 74.8 Medium Volatile Bituminous MVB g/cm³ Samples 63 1764A 313.47 325.47 319.47 11.73 0.9 10.5 25.7 62.9 Washed at 1.6 1.0 28.7 70.3 Medium Volatile Bituminous MVB g/cm³ 64 E 1 0 Raw Coal (Air Dried) 65 E 2 34.89 47.39 41.14 12.5 1.1 15.6 21.0 62.3 Raw Coal (Air Dried) 1.3 24.9 73.8 Medium Volatile Bituminous MVB 66 E 3 33 43.38 38.19 10.38 1.0 13.4 17.4 68.2 Raw Coal (Air Dried) 1.2 20.1 78.8 Low Volatile Bituminous LVB 67 E 3A 33.7 44.53 39.115 10.83 1.2 11.2 20.4 67.2 Raw Coal (Air Dried) 1.4 23.0 75.7 Medium Volatile Bituminous MVB 68 E 4 35.25 46.18 40.715 10.93 0.8 8.9 21.8 68.5 Raw Coal (Air Dried) 0.9 23.9 75.2 Medium Volatile Bituminous MVB 69 E 5 49.68 61.77 55.725 12.09 1.0 8.4 21.6 69.0 Raw Coal (Air Dried) 1.1 23.6 75.3 Medium Volatile Bituminous MVB 183 S e q u e n c e C o m p o s i t e C o a l T h i c k n e s s ( m ) Y i e l d ( % ) M o i s t u r e ( % ) A s h ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) M o i s t u r e ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) Coal Interval Sample Coal Quality Information Coal Rank based on Ash- Mid-Point Free Fixed Carbon, Volatile Ash-Free Matter and Moisture Values Borehole ID / Field Name Analysis Code From (m) To (m) (m) Comments Long Text 70 E 6 486.16 497.13 491.645 10.97 1.2 12.3 17.1 69.4 Raw Coal (Air Dried) 1.4 19.5 79.1 Low Volatile Bituminous LVB 71 E 6 486.16 497.13 491.645 10.97 1.2 19.3 16.8 62.7 Raw Coal (Air Dried) 1.5 20.8 77.7 Low Volatile Bituminous LVB 72 E 7 547.62 559.6 553.61 11.98 1.2 11.9 19.3 67.6 Raw Coal (Air Dried) 1.4 21.9 76.7 Medium Volatile Bituminous MVB 73 E 8 69.11 80.77 74.94 11.66 0.9 7.0 24.6 67.5 Raw Coal (Air Dried) 1.0 26.5 72.6 Medium Volatile Bituminous MVB Raw Coal (Air 74 E 8 69.11 80.77 74.94 11.66 1.4 13.4 20.3 64.9 Dried), Second 1.6 23.4 74.9 Medium Volatile Bituminous MVB Sample Raw Coal (Air 75 E 8 69.11 80.77 74.94 11.66 1.0 22.4 20.5 56.1 Dried), Third 1.3 26.4 72.3 Medium Volatile Bituminous MVB Sample 76 E 9 103.33 115.52 109.425 12.19 1.0 27.6 18.3 53.1 Raw Coal (Air Dried) 1.4 25.3 73.3 Medium Volatile Bituminous MVB 77 E 9A 54.86 64.26 59.56 9.4 0.3 10.5 25.1 64.1 Raw Coal (Air Dried) 0.3 28.0 71.6 Medium Volatile Bituminous MVB 78 E 9A 54.86 64.26 59.56 9.4 1.1 18.9 19.6 60.4 Raw Coal (Air Dried) 1.4 24.2 74.5 Medium Volatile Bituminous MVB 79 E 9A 54.86 64.26 59.56 9.4 1.2 15.9 18.3 64.6 Raw Coal (Air Dried) 1.4 21.8 76.8 Medium Volatile Bituminous MVB 80 E 10 34.16 46.33 40.245 12.17 1.0 8.8 22.1 68.1 Raw Coal (Air Dried) 1.1 24.2 74.7 Medium Volatile Bituminous MVB 81 E 12 47.72 57.06 52.39 9.34 1.0 25.1 20.0 53.9 Raw Coal (Air Dried) 1.3 26.7 72.0 Medium Volatile Bituminous MVB Raw Coal (Air 82 E 12 47.72 57.06 52.39 9.34 0.9 11.5 22.0 65.6 Dried), Second 1.0 24.9 74.1 Medium Volatile Bituminous MVB Sample 83 E 13 32.31 40.81 36.56 8.5 1.7 15.4 20.5 62.4 Raw Coal (Air Dried) 2.0 24.2 73.8 Medium Volatile Bituminous MVB 84 E 15 346.4 359.66 353.03 13.26 1.6 10.9 16.7 70.8 Raw Coal (Air Dried) 1.8 18.7 79.5 Low Volatile Bituminous LVB Raw Coal (Air 85 E 15 346.4 359.66 353.03 13.26 1.6 20.5 17.8 60.1 Dried), Second 2.0 22.4 75.6 Medium Volatile Bituminous MVB Sample 86 E 16A 49.07 62 55.535 12.93 1.3 12.8 21.0 64.9 Raw Coal (Air Dried) 1.5 24.1 74.4 Medium Volatile Bituminous MVB Raw Coal (Air 87 E 16A 49.07 62 55.535 12.93 1.3 16.1 19.7 62.9 Dried), Second 1.5 23.5 75.0 Medium Volatile Bituminous MVB Sample Raw Coal (Air 88 E 16A 49.07 62 55.535 12.93 1.0 7.3 24.6 67.1 Dried), Third 1.1 26.5 72.4 Medium Volatile Bituminous MVB Sample 89 E 17 0 Raw Coal (Air Dried) 90 E 17A 49.53 59.61 54.57 10.08 1.1 11.0 21.3 66.6 Raw Coal (Air Dried) 1.2 23.9 74.8 Medium Volatile Bituminous MVB 91 E 18 57.61 70.02 63.815 12.41 1.7 13.1 17.8 67.4 Raw Coal (Air Dried) 2.0 20.5 77.6 Low Volatile Bituminous LVB 184 S e q u e n c e C o m p o s i t e C o a l T h i c k n e s s ( m ) Y i e l d ( % ) M o i s t u r e ( % ) A s h ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) M o i s t u r e ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) Coal Quality Information Coal Rank based on Ash- Coal Interval Sample Mid-Point Free Fixed Carbon, Volatile Ash-Free Matter and Moisture Values Borehole ID / Field Name Analysis Code From (m) To (m) (m) Comments Long Text Raw Coal (Air 92 E 18 57.61 70.02 63.815 12.41 1.7 12.6 17.8 67.9 Dried), Second 1.9 20.4 77.7 Low Volatile Bituminous LVB Sample Raw Coal (Air 93 E 18 57.61 70.02 63.815 12.41 1.7 10.3 19.6 68.4 Dried), Third 1.9 21.9 76.3 Medium Volatile Bituminous MVB Sample 94 E 19 0 Raw Coal (Air Dried) 95 E 19A 39.01 43.84 41.425 4.83 7.0 10.2 15.2 67.6 Raw Coal (Air Dried) 7.8 16.9 75.3 Medium Volatile Bituminous MVB 96 E 19B 39.01 48.87 43.94 9.86 0.9 12.9 22.0 64.2 Raw Coal (Air Dried) 1.0 25.3 73.7 Medium Volatile Bituminous MVB 97 E 19C 41.15 53.04 47.095 11.89 1.6 14.8 19.6 64.0 Raw Coal (Air Dried) 1.9 23.0 75.1 Medium Volatile Bituminous MVB Raw Coal (Air 98 E 19C 41.15 53.04 47.095 11.89 1.4 12.2 21.0 65.4 Dried), Second 1.6 23.9 74.5 Medium Volatile Bituminous MVB Sample Raw Coal (Air 99 E 19C 41.15 53.04 47.095 11.89 1.1 8.3 25.9 64.7 Dried), Third 1.2 28.2 70.6 Medium Volatile Bituminous MVB Sample 100 E 20 0 Raw Coal (Air Dried) 101 E 21 171 181.98 176.49 10.98 0.5 13.5 19.2 66.8 Raw Coal (Air Dried) 0.6 22.2 77.2 Low Volatile Bituminous LVB 102 E 22 0 Raw Coal (Air Dried) 103 E 24 55.44 65.84 60.64 10.4 0.2 21.5 19.9 58.4 Raw Coal (Air Dried) 0.3 25.4 74.4 Medium Volatile Bituminous MVB Raw Coal (Air 104 E 24 55.44 65.84 60.64 10.4 1.5 11.7 20.1 66.7 Dried), Second 1.7 22.8 75.5 Medium Volatile Bituminous MVB Sample 105 E 25 55.91 67.57 61.74 11.66 1.2 11.2 18.3 69.3 Raw Coal (Air Dried) 1.4 20.6 78.0 Low Volatile Bituminous LVB 106 E 26 94.14 104.1 99.12 9.87 1.5 12.7 18.6 67.2 Raw Coal (Air Dried) 1.7 21.3 77.0 Medium Volatile Bituminous MVB 107 E 27 270.05 281.18 275.615 11.13 1.0 15.5 18.1 65.4 Raw Coal (Air Dried) 1.2 21.4 77.4 Low Volatile Bituminous LVB 108 E 28 0 Raw Coal (Air Dried) 109 E 29 100.58 114.66 107.62 14.08 0.9 12.5 18.2 68.4 Raw Coal (Air Dried) 1.0 20.8 78.2 Low Volatile Bituminous LVB Raw Coal (Air 110 E 29 100.58 114.66 107.62 14.08 0.6 8.1 21.7 69.6 Dried), Second 0.7 23.6 75.7 Medium Volatile Bituminous MVB Sample 111 E 30 53.34 61.57 57.455 8.23 0.7 24.4 18.4 56.5 Raw Coal (Air Dried) 0.9 24.3 74.7 Medium Volatile Bituminous MVB Raw Coal (Air 112 E 30 53.34 61.57 57.455 8.23 0.7 14.8 19.2 65.3 Dried), Second 0.8 22.5 76.6 Medium Volatile Bituminous MVB Sample 113 E 31 161.39 170.38 165.885 8.99 0.7 27.0 19.4 52.9 Raw Coal (Air Dried) 1.0 26.6 72.5 Medium Volatile Bituminous MVB 185 S e q u e n c e C o m p o s i t e C o a l T h i c k n e s s ( m ) Y i e l d ( % ) M o i s t u r e ( % ) A s h ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) M o i s t u r e ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) Coal Interval Sample Coal Quality Information Coal Rank based on Ash- Mid-Point Free Fixed Carbon, Volatile Ash-Free Matter and Moisture Values Borehole ID / Field Name Analysis Code From (m) To (m) (m) Comments Long Text 114 E 32 105.77 114.6 110.185 8.83 0.7 11.5 17.3 70.5 Raw Coal (Air Dried) 0.8 19.5 79.7 Low Volatile Bituminous LVB Raw Coal (Air 115 E 32 105.77 114.6 110.185 8.83 0.8 8.3 21.2 69.7 Dried), Second 0.9 23.1 76.0 Medium Volatile Bituminous MVB Sample 116 E 33 89.97 100.35 95.16 10.38 1.2 22.2 18.4 58.2 Raw Coal (Air Dried) 1.5 23.7 74.8 Medium Volatile Bituminous MVB Raw Coal (Air 117 E 33 89.97 100.35 95.16 10.38 1.2 9.2 20.6 69.0 Dried), Second 1.3 22.7 76.0 Medium Volatile Bituminous MVB Sample 118 E 34 161.08 173.35 167.215 12.27 0.3 11.5 18.9 69.3 Raw Coal (Air Dried) 0.3 21.4 78.3 Low Volatile Bituminous LVB Raw Coal (Air 119 E 34 161.08 173.35 167.215 12.27 1.0 10.2 18.8 70.0 Dried), Second 1.1 20.9 78.0 Low Volatile Bituminous LVB Sample Raw Coal (Air 120 E 34 161.08 173.35 167.215 12.27 0.6 12.1 23.8 63.6 Dried), Third 0.7 27.1 72.4 Medium Volatile Bituminous MVB Sample 121 E 35 170.69 180.74 175.715 10.05 0.9 10.1 20.7 68.3 Raw Coal (Air Dried) 1.0 23.0 76.0 Medium Volatile Bituminous MVB 122 E 36 204.08 212.58 208.33 8.5 1.4 22.9 18.2 57.5 Raw Coal (Air Dried) 1.8 23.6 74.6 Medium Volatile Bituminous MVB Raw Coal (Air 123 E 37 256.64 265.18 260.91 8.54 0.9 19.9 17.9 61.3 Dried), General quality for deep 1.1 22.3 76.5 Medium Volatile Bituminous MVB area used Raw Coal (Air 124 E 38 329.79 332.38 331.085 2.59 0.9 19.9 17.9 61.3 Dried), General quality for deep 1.1 22.3 76.5 Medium Volatile Bituminous MVB area used 125 E 39 53.04 66.55 59.795 13.51 1.3 19.3 18.1 61.3 Raw Coal (Air Dried) 1.6 22.4 76.0 Medium Volatile Bituminous MVB 126 E 40 37.8 50.9 44.35 13.1 1.0 20.7 18.9 59.4 Raw Coal (Air Dried) 1.3 23.8 74.9 Medium Volatile Bituminous MVB 127 E 41 43.93 55.93 49.93 12 1.2 19.9 18.2 60.7 Raw Coal (Air Dried) 1.5 22.7 75.8 Medium Volatile Bituminous MVB 128 E 42 52.58 64.58 58.58 12 1.2 18.4 18.5 61.9 Raw Coal (Air Dried) 1.5 22.7 75.9 Medium Volatile Bituminous MVB 129 E 43 55.56 67.56 61.56 12 1.2 19.3 18.6 60.9 Raw Coal (Air Dried) 1.5 23.0 75.5 Medium Volatile Bituminous MVB 130 E 44 49.99 53.77 51.88 3.78 1.5 11.4 13.0 74.1 Raw Coal (Air Dried) 1.7 14.7 83.6 Low Volatile Bituminous LVB 131 E 45 8.53 20.37 14.45 11.84 1.3 15.5 21.3 61.9 Raw Coal (Total Seam) 1.5 25.2 73.3 Medium Volatile Bituminous MVB 132 E 46 31.23 41.8 36.515 10.57 0.6 15.5 21.5 62.4 Raw Coal (Total Seam) 0.7 25.4 73.8 Medium Volatile Bituminous MVB 133 E 47 37.19 48.52 42.855 11.33 1.4 22.1 19.3 57.2 Raw Coal (Total Seam) 1.8 24.8 73.4 Medium Volatile Bituminous MVB 134 E 48 42.98 56.69 49.835 13.71 1.2 24.4 18.1 56.3 Raw Coal (Total Seam) 1.6 23.9 74.5 Medium Volatile Bituminous MVB 186 S e q u e n c e C o m p o s i t e C o a l T h i c k n e s s ( m ) Y i e l d ( % ) M o i s t u r e ( % ) A s h ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) M o i s t u r e ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) Coal Quality Information Coal Rank based on Ash- Coal Interval Sample Mid-Point Free Fixed Carbon, Volatile Ash-Free Matter and Moisture Values Borehole ID / Field Name Analysis Code From (m) To (m) (m) Comments Long Text 135 E 49 50.9 60.86 55.88 9.96 1.2 18.0 21.4 59.4 Raw Coal (Total Seam) 1.5 26.1 72.4 Medium Volatile Bituminous MVB 136 E 50 49.02 61.23 55.125 12.21 1.3 19.9 20.2 58.6 Raw Coal (Total Seam) 1.6 25.2 73.2 Medium Volatile Bituminous MVB 137 E 51 33.51 46.8 40.155 13.29 1.2 23.0 19.0 56.8 Raw Coal (Total Seam) 1.6 24.7 73.8 Medium Volatile Bituminous MVB 138 E 52 45.09 59.21 52.15 14.12 0.9 22.0 19.8 57.3 Raw Coal (Total Seam) 1.2 25.4 73.5 Medium Volatile Bituminous MVB 139 E 53 42.67 52.88 47.775 10.21 1.3 15.0 19.9 63.8 Raw Coal (Total Seam) 1.5 23.4 75.1 Medium Volatile Bituminous MVB 140 E 54 81.08 92.81 86.945 11.73 0.4 18.3 20.7 60.6 Raw Coal (Total Seam) 0.5 25.3 74.2 Medium Volatile Bituminous MVB 141 E 55 102.11 115.66 108.885 13.55 1.1 20.6 18.9 59.4 Raw Coal (Total Seam) 1.4 23.8 74.8 Medium Volatile Bituminous MVB 142 E 56 39.93 51.77 45.85 11.84 1.2 15.0 20.2 63.6 Raw Coal (Total Seam) 1.4 23.8 74.8 Medium Volatile Bituminous MVB 143 E 57 137.33 147.68 142.505 10.35 1.0 15.1 19.7 64.2 Raw Coal (Total Seam) 1.2 23.2 75.6 Medium Volatile Bituminous MVB 144 E 58 160.43 172.73 166.58 12.3 0.9 19.5 18.7 60.9 Raw Coal (Total Seam) 1.1 23.2 75.7 Medium Volatile Bituminous MVB 145 E 59 35.29 51.06 43.175 15.77 1.5 17.2 20.2 61.1 Raw Coal (Total Seam) 1.8 24.4 73.8 Medium Volatile Bituminous MVB 146 E 60 188.06 199.17 193.615 11.11 0.7 19.3 20.7 59.3 Raw Coal (Total Seam) 0.9 25.7 73.5 Medium Volatile Bituminous MVB 147 E 61 185.17 200.67 192.92 15.5 1.0 26.0 18.1 54.9 Raw Coal (Total Seam) 1.4 24.5 74.2 Medium Volatile Bituminous MVB 148 E 62 46.35 61.73 54.04 15.38 1.6 17.7 19.8 60.9 Raw Coal (Total Seam) 1.9 24.1 74.0 Medium Volatile Bituminous MVB 149 E 63 210.64 222.73 216.685 12.09 1.1 24.5 18.2 56.2 Raw Coal (Total Seam) 1.5 24.1 74.4 Medium Volatile Bituminous MVB Raw Coal (Air 150 E 64 210.08 230.42 220.25 20.34 0.9 19.9 17.9 61.3 Dried), General quality for deep 1.1 22.3 76.5 Medium Volatile Bituminous MVB area used 151 E 65 89.81 99.16 94.485 9.98 1.2 20.4 18.0 60.4 Raw Coal (Total Seam) 1.5 22.6 75.9 Medium Volatile Bituminous MVB 152 E 66 94.67 106.96 100.815 12.29 0.6 21.0 19.2 59.4 Raw Coal (Total Seam) 0.8 24.3 75.2 Medium Volatile Bituminous MVB 153 E 66A 94.59 105.73 100.16 11.14 1.1 19.8 18.5 60.6 Raw Coal (Total Seam) 1.4 23.1 75.6 Medium Volatile Bituminous MVB 154 E 67 76.88 89.99 83.435 13.11 1.4 22.9 17.5 58.2 Raw Coal (Total Seam) 1.8 22.7 75.5 Medium Volatile Bituminous MVB 155 E 68 74.19 87.99 81.09 13.8 1.2 21.9 18.4 58.5 Raw Coal (Total Seam) 1.5 23.6 74.9 Medium Volatile Bituminous MVB 156 E 69 140.85 153.54 147.195 12.69 1.0 15.9 17.9 65.2 Raw Coal (Total Seam) 1.2 21.3 77.5 Low Volatile Bituminous LVB 187 S e q u e n c e C o m p o s i t e C o a l T h i c k n e s s ( m ) Y i e l d ( % ) M o i s t u r e ( % ) A s h ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) M o i s t u r e ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) Coal Quality Information Coal Rank based on Ash- Coal Interval Sample Mid-Point Free Fixed Carbon, Volatile Ash-Free Matter and Moisture Values Borehole ID / Field Name Analysis Code From (m) To (m) (m) Comments Long Text 157 E 70 150.27 160.67 155.47 10.4 0.8 18.1 19.5 61.6 Raw Coal (Total Seam) 1.0 23.8 75.2 Medium Volatile Bituminous MVB 158 E 71 151.91 161.46 156.685 9.55 0.9 22.8 18.5 57.8 Raw Coal (Total Seam) 1.2 24.0 74.9 Medium Volatile Bituminous MVB 159 E 72 144.13 152.9 148.515 8.77 0.8 19.6 18.5 61.1 Raw Coal (Total Seam) 1.0 23.0 76.0 Medium Volatile Bituminous MVB 160 E 73 203.05 214.63 208.84 11.58 1.0 20.7 17.3 61.0 Raw Coal (Total Seam) 1.3 21.8 76.9 Medium Volatile Bituminous MVB 161 E 74 183.99 194.54 189.265 10.55 0.9 19.0 18.3 61.8 Raw Coal (Total Seam) 1.1 22.6 76.3 Medium Volatile Bituminous MVB 162 E 75 189.2 197.66 193.43 8.46 0.9 31.8 16.9 50.4 Raw Coal (Total Seam) 1.3 24.8 73.9 Medium Volatile Bituminous MVB 163 E 76 176.02 180.12 178.07 4.1 0.6 15.8 18.8 64.8 Raw Coal (Total Seam) 0.7 22.3 77.0 Medium Volatile Bituminous MVB 164 E 77 243.75 254.66 249.205 10.91 1.0 19.4 16.8 62.8 Raw Coal (Total Seam) 1.2 20.8 77.9 Low Volatile Bituminous LVB 165 E 78 226.49 237.38 231.935 10.89 1.0 18.6 17.5 62.9 Raw Coal (Total Seam) 1.2 21.5 77.3 Low Volatile Bituminous LVB 166 E 79 226.1 235.93 231.015 9.83 0.8 22.9 17.1 59.2 Raw Coal (Total Seam) 1.0 22.2 76.8 Medium Volatile Bituminous MVB 167 E 80B 246.14 255.4 250.77 9.26 1.0 18.4 18.4 62.2 Raw Coal (Total Seam) 1.2 22.5 76.2 Medium Volatile Bituminous MVB 168 E 81 241.28 249.18 245.23 7.82 0.8 19.4 17.0 62.8 Raw Coal (Total Seam) 1.0 21.1 77.9 Low Volatile Bituminous LVB 169 E 82 325.23 333.69 329.46 8.46 0.9 22.1 17.7 59.3 Raw Coal (Total Seam) 1.2 22.7 76.1 Medium Volatile Bituminous MVB 170 E 83 314.62 323.22 318.92 8.6 0.9 19.5 17.9 61.7 Raw Coal (Total Seam) 1.1 22.2 76.6 Medium Volatile Bituminous MVB 171 E 84 261.14 269.66 265.4 8.52 1.0 20.2 17.5 61.3 Raw Coal (Total Seam) 1.3 21.9 76.8 Medium Volatile Bituminous MVB 172 E 85 315.49 323.26 319.375 7.77 0.8 25.4 16.5 57.3 Raw Coal (Total Seam) 1.1 22.1 76.8 Medium Volatile Bituminous MVB Raw Coal (Air 173 E 87 6.08 10.5 8.29 4.42 1.1 18.9 19.6 60.4 Dried), General quality for open 1.4 24.2 74.5 Medium Volatile Bituminous MVB cast area used 174 E 88 53.54 63.85 58.695 10.31 1.1 18.9 19.6 60.4 Raw Coal (Total Seam) 1.4 24.2 74.5 Medium Volatile Bituminous MVB 175 E 89 48.46 52.94 50.7 4.48 1.1 18.9 19.6 60.4 Raw Coal (Total Seam) 1.4 24.2 74.5 Medium Volatile Bituminous MVB 176 E 90 38.6 48.87 43.735 10.27 1.1 9.8 20.9 68.2 Raw Coal (Total Seam) 1.2 23.2 75.6 Medium Volatile Bituminous MVB 177 E 91 49.38 61.1 55.24 11.72 0.9 11.4 21.5 66.2 Raw Coal (Total Seam) 1.0 24.3 74.7 Medium Volatile Bituminous MVB 178 E 92 47.5 59.08 53.29 11.58 1.1 18.9 19.6 60.4 Raw Coal (Total Seam) 1.4 24.2 74.5 Medium Volatile Bituminous MVB 188 S e q u e n c e C o m p o s i t e C o a l T h i c k n e s s ( m ) Y i e l d ( % ) M o i s t u r e ( % ) A s h ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) M o i s t u r e ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) Coal Interval Sample Coal Quality Information Coal Rank based on Ash- Mid-Point Free Fixed Carbon, Volatile Ash-Free Matter and Moisture Values Borehole ID / Field Name Analysis Code From (m) To (m) (m) Comments Long Text Raw Coal (Air 179 E 93 64.22 64.22 1.1 18.9 19.6 60.4 Dried), General quality for open 1.4 24.2 74.5 Medium Volatile Bituminous MVB cast area used 180 E 94 58.92 69.31 64.115 10.39 1.1 18.9 19.6 60.4 Raw Coal (Total Seam) 1.4 24.2 74.5 Medium Volatile Bituminous MVB 181 E 96 0 Raw Coal (Total Seam) 182 E 97 0 Raw Coal (Total Seam) Raw Coal (Air 183 E 98 110.5 121.6 116.05 11.1 0.9 19.9 17.9 61.3 Dried), General quality for deep 1.1 22.3 76.5 Medium Volatile Bituminous MVB area used Raw Coal (Air 184 E 99 218.85 227.13 222.99 8.28 0.9 19.9 17.9 61.3 Dried), General quality for deep 1.1 22.3 76.5 Medium Volatile Bituminous MVB area used Raw Coal (Air 185 E 101 229.08 238.44 233.76 9.36 0.9 19.9 17.9 61.3 Dried), General quality for deep 1.1 22.3 76.5 Medium Volatile Bituminous MVB area used Raw Coal (Air 186 E 102 201.8 210.6 206.2 8.8 0.9 19.9 17.9 61.3 Dried), General quality for deep 1.1 22.3 76.5 Medium Volatile Bituminous MVB area used 187 E 103 93.46 101.82 97.64 8.36 1.1 18.9 19.6 60.4 Raw Coal (Total Seam) 1.4 24.2 74.5 Medium Volatile Bituminous MVB Raw Coal (Air 188 E 104 119.41 125.83 122.62 6.42 0.9 19.9 17.9 61.3 Dried), General quality for deep 1.1 22.3 76.5 Medium Volatile Bituminous MVB area used 189 LBW 1 11.12 13.14 12.13 2.02 1.1 37.6 25.9 35.4 Raw Coal (Air Dried) 1.8 41.5 56.7 High Volatile Bituminous - B HVB-B 190 LBW 1 16.17 20.23 18.2 3.73 1.0 41.7 22.2 35.1 Raw Coal (Air Dried) 1.7 38.1 60.2 High Volatile Bituminous - B HVB-B Raw Coal (Air 191 LBW 1 28.82 43.33 36.075 1.1 27.3 23.4 48.2 Dried), General quality 1.5 32.2 66.3 information used 192 LBW 1 0 10.53 1.0 29.9 23.4 45.7 Raw Coal (Air Dried) 1.4 33.4 65.2 High Volatile Bituminous - A HVB-A 193 LBW 2 84.71 88.66 86.685 2.8 1.1 39.0 24.2 35.5 Raw Coal (Air Dried) 1.8 39.7 58.2 High Volatile Bituminous - B HVB-B Raw Coal (Air 194 LBW 2 95.94 111.56 103.75 1.1 27.3 23.4 48.2 Dried), General quality 1.5 32.2 66.3 information used 195 LBW 2 0 13.57 1.1 23.7 22.0 53.2 Raw Coal (Air Dried) 1.4 28.8 69.7 Medium Volatile Bituminous MVB 189 S e q u e n c e C o m p o s i t e C o a l T h i c k n e s s ( m ) Y i e l d ( % ) M o i s t u r e ( % ) A s h ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) M o i s t u r e ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) Coal Interval Sample Coal Quality Information Coal Rank based on Ash- Mid-Point Free Fixed Carbon, Volatile Ash-Free Matter and Moisture Values Borehole ID / Field Name Analysis Code From (m) To (m) (m) Comments Long Text 196 LBW 4 41.51 43.51 42.51 2 1.0 34.6 25.0 39.4 Raw Coal (Air Dried) 1.5 38.2 60.2 High Volatile Bituminous - B HVB-B 197 LBW 4 51.9 70.13 61.015 17.92 1.0 24.7 23.0 51.3 Raw Coal (Air Dried) 1.3 30.5 68.1 High Volatile Bituminous - A HVB-A 198 LBW 5 32.76 36.41 34.585 3.26 0.9 46.6 21.1 31.5 Raw Coal (Air Dried) 1.7 39.5 59.0 High Volatile Bituminous - B HVB-B 199 LBW 5 40.53 56.83 48.68 16.2 0.9 27.6 23.9 47.6 Raw Coal (Air Dried) 1.2 33.0 65.7 High Volatile Bituminous - A HVB-A Raw Coal (Air 200 LBW 6 65.61 74.1 69.855 9.09 1.1 27.3 23.4 48.2 Dried), General quality 1.5 32.2 66.3 information used 201 LBW 6 15 98 56.5 7.96 0.9 44.1 18.4 30.8 Raw Coal (Air Dried) 1.6 32.9 55.1 High Volatile Bituminous - B HVB-B 202 LBW 6 83.56 92.7 88.13 8.65 1.0 23.9 25.6 49.5 Raw Coal (Air Dried) 1.3 33.6 65.0 High Volatile Bituminous - A HVB-A 203 LBW 7 55.05 58.99 57.02 3.69 1.0 43.5 22.2 33.4 Raw Coal (Air Dried) 1.8 39.3 59.1 High Volatile Bituminous - B HVB-B 204 LBW 7 64.65 82.28 73.465 15.68 1.0 32.4 23.1 43.5 Raw Coal (Air Dried) 1.5 34.2 64.3 High Volatile Bituminous - A HVB-A 205 LBW 8 25.64 29.43 27.535 3.43 0.8 42.5 20.9 35.8 Raw Coal (Air Dried) 1.4 36.3 62.3 High Volatile Bituminous - A HVB-A 206 LBW 8 34.9 46.35 40.625 9.31 0.9 25.8 24.2 49.1 Raw Coal (Air Dried) 1.2 32.6 66.2 High Volatile Bituminous - A HVB-A 207 LBW 9 14.81 16.81 15.81 1.91 1.1 35.3 25.1 38.5 Raw Coal (Air Dried) 1.7 38.8 59.5 High Volatile Bituminous - B HVB-B 208 LBW 9 26.6 34.58 30.59 7.98 0.9 32.3 22.3 44.5 Raw Coal (Air Dried) 1.3 32.9 65.7 High Volatile Bituminous - A HVB-A 209 LBW 10 63.13 67.19 65.16 3.74 1.1 38.5 20.8 34.9 Raw Coal (Air Dried) 1.8 33.8 56.7 High Volatile Bituminous - B HVB-B 210 LBW 10 73.22 84.3 78.76 10.98 0.9 29.2 21.9 48.0 Raw Coal (AirDried) 1.3 30.9 67.8 High Volatile Bituminous - A HVB-A 211 LBW 11 32.11 36.16 34.135 1.7 1.6 37.9 24.3 37.8 Raw Coal (Air Dried) 2.6 39.1 60.9 High Volatile Bituminous - B HVB-B Raw Coal (Air 212 LBW 11 44.04 57.16 50.6 13.12 1.1 27.3 23.4 48.2 Dried), General quality 1.5 32.2 66.3 information used 213 LBW 11 0 12.3 2.7 24.6 25.3 47.4 Raw Coal (Air Dried) 3.6 33.6 62.9 High Volatile Bituminous - A HVB-A 214 LBW 12 39.86 50.87 45.365 6.13 2.2 40.3 23.7 33.8 Raw Coal (Air Dried) 3.7 39.7 56.6 High Volatile Bituminous - B HVB-B 215 LBW 12 66.3 79.84 73.07 12.57 2.1 20.4 21.3 56.2 Raw Coal (Air Dried) 2.6 26.8 70.6 Medium Volatile Bituminous MVB 216 LBW 13 97.77 102 99.885 4.04 0.8 39.3 18.7 41.2 Raw Coal (Air Dried) 1.3 30.8 67.9 High Volatile Bituminous - A HVB-A 217 S 1 96.01 113.08 104.545 17.07 3.8 26.2 24.4 45.6 Raw Coal 5.1 33.1 61.8 High Volatile Bituminous - B HVB-B 218 S 2 63.93 77.62 70.775 13.69 4.4 22.9 21.6 51.1 Raw Coal 5.7 28.0 66.3 High Volatile Bituminous - A HVB-A 219 S 3 6.1 15.24 10.67 9.14 4.4 27.3 20.6 47.7 Raw Coal 6.1 28.3 65.6 High Volatile Bituminous - A HVB-A 220 S 5 90.22 107.29 98.755 17.07 5.2 17.7 20.9 56.2 Raw Coal 6.3 25.4 68.3 High Volatile Bituminous - A HVB-A 190 S e q u e n c e C o m p o s i t e C o a l T h i c k n e s s ( m ) Y i e l d ( % ) M o i s t u r e ( % ) A s h ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) M o i s t u r e ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) Coal Quality Information Coal Rank based on Ash- Coal Interval Sample Mid-Point Free Fixed Carbon, Volatile Ash-Free Matter and Moisture Values Borehole ID / Field Name Analysis Code From (m) To (m) (m) Comments Long Text 221 S 18 151.79 160.55 156.17 8.76 2.8 19.4 26.6 51.2 Raw Coal 3.5 33.0 63.5 High Volatile Bituminous - A HVB-A 222 S 25 147.51 159.4 153.455 11.89 3.2 25.8 21.3 49.7 Raw Coal 4.3 28.7 67.0 High Volatile Bituminous - A HVB-A 223 S 26 11.27 21.96 16.615 10.69 3.6 26.5 18.6 51.3 Raw Coal 4.9 25.3 69.8 Medium Volatile Bituminous MVB 224 S 27 85.8 97.92 91.86 12.12 3.4 22.9 21.0 52.7 Raw Coal 4.4 27.2 68.4 High Volatile Bituminous - A HVB-A 225 S 29 70.71 80.95 75.83 10.24 3.6 22.8 21.4 52.2 Raw Coal 4.7 27.7 67.6 High Volatile Bituminous - A HVB-A 226 S 30 40.46 49.48 44.97 9.02 5.1 11.5 22.0 61.4 Raw Coal 5.8 24.9 69.4 Medium Volatile Bituminous MVB 227 M 1 78.59 90.53 84.56 11.94 3.0 27.2 22.3 47.5 Raw Coal 4.1 30.6 65.2 High Volatile Bituminous - A HVB-A 228 M 2 96.32 111.51 103.915 15.19 3.0 27.7 21.8 47.5 Raw Coal 4.1 30.2 65.7 High Volatile Bituminous - A HVB-A 229 M 3 78.93 93.26 86.095 14.33 3.6 17.5 23.5 55.4 Raw Coal 4.4 28.5 67.2 High Volatile Bituminous - A HVB-A 230 M 4 135.62 145 140.31 9.38 3.3 24.2 23.0 49.5 Raw Coal 4.4 30.3 65.3 High Volatile Bituminous - A HVB-A 231 M 5 69.18 78.84 74.01 9.66 2.2 26.9 23.1 47.8 Raw Coal 3.0 31.6 65.4 High Volatile Bituminous - A HVB-A 232 M 6 71.11 78.93 75.02 7.82 2.0 37.6 20.7 39.7 Raw Coal 3.2 33.2 63.6 High Volatile Bituminous - A HVB-A 233 M 7 108.35 118.56 113.455 10.21 3.6 18.3 23.0 55.1 Raw Coal 4.4 28.2 67.4 High Volatile Bituminous - A HVB-A 234 M 8 71.85 83.28 77.565 11.43 4.0 21.9 22.0 52.1 Raw Coal 5.1 28.2 66.7 High Volatile Bituminous - A HVB-A 235 M 9 21.18 34.51 27.845 13.33 5.0 18.7 21.5 54.8 Raw Coal 6.2 26.4 67.4 High Volatile Bituminous - A HVB-A 236 M 10 0.1 11.07 5.585 11.07 5.3 18.2 21.5 55.0 Raw Coal 6.5 26.3 67.2 High Volatile Bituminous - A HVB-A 237 M 11 25.75 38.63 32.19 12.88 4.5 20.6 20.4 54.5 Raw Coal 5.7 25.7 68.6 High Volatile Bituminous - A HVB-A L 256 (Type Borehole - Raw Coal -238 Main & A Seams)* 15 190 102.5 9.17 12.0 18.8 24.1 45.1 Fixed Carbon 14.8 29.7 55.5 High Volatile Bituminous - B HVB-BCalculated 239 L 252 (Type Borehole - 22.49766 197.4976 109.9976 Raw Coal - Main Seam)* 667 667 667 6.15 13.5 16.0 27.4 43.1 Fixed Carbon 16.1 32.6 51.3 High Volatile Bituminous - C HVB-CCalculated 240 L 198 (Type Borehole - Raw Coal - Lower & Middle Seam)* 26.6 97.77 62.185 4.15 11.9 13.0 29.3 45.8 Fixed Carbon 13.7 33.7 52.6 High Volatile Bituminous - C HVB-CCalculated High ash bright thin bands with 241 Shallow (Average)* 60 100 80 9 0.8 9.8 23.8 65.8 interbedded mudstone 0.8 26.3 72.9 Medium Volatile Bituminous MVB reported, some Fischer oil noted High ash bright thin bands with 242 Deep(Average)* 200 700 450 9 0.8 9.8 23.8 65.8 interbedded 0.8 26.3 72.9 Medium Volatile Bituminous MVB mudstone reported 191 S e q u e n c e C o m p o s i t e C o a l T h i c k n e s s ( m ) Y i e l d ( % ) M o i s t u r e ( % ) A s h ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) M o i s t u r e ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) Sample Coal Quality Information Coal Rank based on Ash-Coal Interval Mid-Point Free Fixed Carbon, Volatile Ash-Free Matter and Moisture Values Borehole ID / Field Name Analysis Code From (m) To (m) (m) Comments Long Text Reported by Padcoal (Pvt) Ltd (2011) as part of an investment 243 Gokwe Average 200 300 250 9 4.0 25.0 22.0 49.0 brochure. Ash 5.3 29.3 65.3 High Volatile Bituminous - A HVB-A values reported as between 20 & 30 % by Oesterlen & Lepper (2005) No Analysis Data Provided. 244 N1/1 45.1 46.7 45.9 1 High ash lower Subbituminous SBIT quality coal. Report No Analysis Data Provided. 245 N1/2 41 89 65 5.5 High ash lower Subbituminous SBIT quality coal. Report No Analysis Data Provided. 246 N1/3 24 91 57.5 7.73 High ash lower Subbituminous SBIT quality coal. Report No Analysis Data Provided. 247 N2/1 52.7 118.1 85.4 19.6 High ash lower Subbituminous SBIT quality coal. Report No Analysis Data Provided. 248 N3/1 38.3 119 78.65 23.65 High ash lower Subbituminous SBIT quality coal. Report No Analysis Data Provided. 249 N4/1 113.3 189 151.15 14.03 High ash lower Subbituminous SBIT quality coal. Report No Analysis Data Provided. 250 N5/2 5 41.7 23.35 6.8 High ash lower Subbituminous SBIT quality coal. Report No Analysis Data Provided. 251 N5/1 10.4 41.2 25.8 4.1 High ash lower Subbituminous SBIT quality coal. Report 192 S e q u e n c e C o m p o s i t e C o a l T h i c k n e s s ( m ) Y i e l d ( % ) M o i s t u r e ( % ) A s h ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) M o i s t u r e ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) Coal Quality Information Coal Rank based on Ash- Coal Interval Sample Mid-Point Free Fixed Carbon, Volatile Ash-Free Matter and Moisture Values Borehole ID / Field Name Analysis Code From (m) To (m) (m) Comments Long Text No Analysis Data Provided. 252 N6/1 14.7 70.5 42.6 2.5 High ash lower Subbituminous SBIT quality coal. Report No Analysis Data Provided. 253 N8/2 75.35 124.5 99.925 11.5 High ash lower Subbituminous SBIT quality coal. Report No Analysis Data Provided. 254 N12/1 79.9 150.85 115.375 12.5 High ash lower Subbituminous SBIT quality coal. Report No Analysis Data Provided. 255 N9/1 75.4 124.6 100 8.74 High ash lower Subbituminous SBIT quality coal. Report No Analysis Data Provided. 256 N10/1 89.4 177.3 133.35 21.76 High ash lower Subbituminous SBIT quality coal. Report No Analysis Data Provided. 257 N11/3 110.6 153.5 132.05 8.15 High ash lower Subbituminous SBIT quality coal. Report 258 N7/1 0 No Coal Intersected 259 N7/2 0 No Coal Intersected 260 N7/3 0 No Coal Intersected 261 N8/1 0 No Coal Intersected 262 N8/2 0 No Coal Intersected 263 N12/1 0 No Coal Intersected 264 N9/1 0 No Coal Intersected 265 N10/1 0 No Coal Intersected 266 N11/3 0 No Coal Intersected 267 N11/2 0 No Coal Intersected 268 N11/1 0 No Coal 193 S e q u e n c e C o m p o s i t e C o a l T h i c k n e s s ( m ) Y i e l d ( % ) M o i s t u r e ( % ) A s h ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) M o i s t u r e ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) Sample Coal Quality Information Coal Rank based on Ash-Coal Interval Mid-Point Free Fixed Carbon, Volatile Ash-Free Matter and Moisture Values Borehole ID / Field Name Analysis Code From (m) To (m) (m) Comments Long Text Intersected 269 N12/1 0 No Coal Intersected 270 N12/2 0 No Coal Intersected 271 N12/3 0 No Coal Intersected No Analysis Data Provided. 272 Y1-01 499.74 566.3 533.02 10.652 High ash lower quality coal. Subbituminous SBIT Only developed in the Nata Area No Analysis Data Provided. 273 Y1-02 705.536 737.136 721.336 1.29 High ash lower quality coal. Subbituminous SBIT Only developed in the Nata Area No Analysis Data Provided. 274 Y1-03 705.73 792.74 749.235 16.75 High ash lower quality coal. Subbituminous SBIT Only developed in the Nata Area No Analysis Data Provided. 275 Y1-04 587.2 605.5 596.35 2.85 High ash lower quality coal. Subbituminous SBIT Only developed in the Nata Area 276 PDM006C 0 No Coal Intersected 277 PDM007A 0 No Coal Intersected 278 PDM008 0 No Coal Intersected 279 PDM009 0 No Coal Intersected 280 PDM011 0 No Coal Intersected 281 PDM014A 0 No Coal Intersected 282 PDM015 0 No Coal Intersected 194 S e q u e n c e C o m p o s i t e C o a l T h i c k n e s s ( m ) Y i e l d ( % ) M o i s t u r e ( % ) A s h ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) M o i s t u r e ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) Sample Coal Quality Information Coal Rank based on Ash-Coal Interval Mid-Point Free Fixed Carbon, Volatile Ash-Free Matter and Moisture Values Borehole ID / Field Name Analysis Code From (m) To (m) (m) Comments Long Text High ash bright thin bands with interbedded mudstone 283 Lubimbi 11.8 190 100.9 reported, some Fischer oil High Volatile Bituminous C HVB-C noted. High Volatile Bituminous B Assumed High ash lower 284 Busi 60 80 70 10 quality coal Subbituminous SBIT reported High ash lower 285 Tjolotjo, Sawmills, and quality coal Insuza 270 330 300 5 reported Subbituminous SBIT (bituminous) 195 S e q u e n c e C o m p o s i t e C o a l T h i c k n e s s ( m ) Y i e l d ( % ) M o i s t u r e ( % ) A s h ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) M o i s t u r e ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) Appendix C Schedule of borehole data showing the Gas Content Calculated from the Eddy, et al. (1982) trend line Equations used in this evaluation. Coal Interval Coal Quality Gas Content Calculated from Eddy, et al. (1982) Trend Line Equations (scf/T) Ash-Free Full Saturation (100%) 75% Saturation 50% Saturation 25% SaturationBorehole ID / Eddy, et al. (1982) Trend Field Name\ Sample Coal Line Equation From (m) To (m) Mid-Point Rank (m) Code 1 M 53 284.19 291.57 287.88 7.38 1.2 27.4 71.4 MVB y = 122.88ln(x) - 305.91 388 391 390 291 294 292 194 196 195 97 98 97 2 M 55 288.81 294.5 291.655 5.69 1.2 26.1 72.7 MVB y = 122.88ln(x) - 305.91 390 393 392 293 295 294 195 196 196 98 98 98 3 M 56 249.09 254.76 251.925 5.67 1.3 25.4 73.3 MVB y = 122.88ln(x) - 305.91 372 375 374 279 281 280 186 187 187 93 94 93 4 M 57 281.96 287.22 284.59 5.26 1.1 29.0 69.9 MVB y = 122.88ln(x) - 305.91 387 390 388 291 292 291 194 195 194 97 97 97 5 M 58 243 252.28 247.64 9.28 1.2 27.4 71.4 MVB y = 122.88ln(x) - 305.91 369 374 371 277 280 279 185 187 186 92 93 93 6 M 59 287.1 294.98 291.04 7.88 1.1 28.2 70.8 MVB y = 122.88ln(x) - 305.91 390 393 391 292 295 293 195 196 196 97 98 98 7 M 60 279.04 287.36 283.2 8.32 1.3 28.1 70.6 MVB y = 122.88ln(x) - 305.91 386 390 388 290 292 291 193 195 194 97 97 97 8 M 62 259.91 266.36 263.135 6.45 1.3 29.8 68.9 HVB-A y = 78.864ln(x) - 193.00 246 247 246 184 186 185 123 124 123 61 62 62 9 M 63 252.67 258.78 255.725 6.11 1.3 32.7 66.0 HVB-A y = 78.864ln(x) - 193.00 243 245 244 182 184 183 122 123 122 61 61 61 10 M 64 251.54 253.6 252.57 2.06 1.2 25.4 73.4 MVB y = 122.88ln(x) - 305.91 373 374 374 280 281 280 187 187 187 93 94 93 11 M 65 88.63 103.81 96.22 9.46 1.2 36.1 62.6 HVB-A y = 78.864ln(x) - 193.00 161 173 167 120 130 125 80 87 84 40 43 42 12 M 66 35.19 48.38 41.785 7.39 1.3 36.8 61.9 HVB-B y = 52.803ln(x) - 141.04 47 64 56 35 48 42 23 32 28 12 16 14 13 M 67 24.7 34.33 29.515 3.9 1.4 37.1 61.5 HVB-B y = 52.803ln(x) - 141.04 (1) 46 (1) (1) 34 (1) (1) 23 (1) (1) 11 (1) 14 M 68 15.31 24.03 19.67 6.27 2.1 23.2 74.8 MVB y = 122.88ln(x) - 305.91 (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) 15 M 69 100.61 109.31 104.96 5.72 1.4 36.6 62.0 HVB-A y = 78.864ln(x) - 193.00 171 177 174 128 133 130 85 89 87 43 44 43 16 M 70 55.51 71.32 63.415 8.2 1.3 36.0 62.7 HVB-A y = 78.864ln(x) - 193.00 124 144 134 93 108 101 62 72 67 31 36 34 17 M 71 15.75 31.62 23.685 9.2 1.6 35.7 62.7 HVB-A y = 78.864ln(x) - 193.00 (1) 79 (1) (1) 60 (1) (1) 40 (1) (1) 20 (1) 18 M 72 110.65 123.89 117.27 9.65 1.2 35.4 63.4 HVB-A y = 78.864ln(x) - 193.00 178 187 183 134 140 137 89 94 91 45 47 46 19 M 73 99.06 116.83 107.945 8.7 1.6 35.6 62.8 HVB-A y = 78.864ln(x) - 193.00 169 182 176 127 137 132 85 91 88 42 46 44 20 M 74 69.18 85.98 77.58 10.11 1.7 34.8 63.5 HVB-A y = 78.864ln(x) - 193.00 141 158 150 106 119 113 71 79 75 35 40 38 21 M 75 33 51.43 42.215 13.91 2.0 34.8 63.2 HVB-A y = 78.864ln(x) - 193.00 83 118 102 62 88 77 41 59 51 21 29 26 22 M 76 14.02 19.75 16.885 5.73 2.1 23.2 74.8 MVB y = 122.88ln(x) - 305.91 (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) 23 M 77 87.78 113.39 100.585 7.76 1.7 34.8 63.6 HVB-A y = 78.864ln(x) - 193.00 160 180 171 120 135 128 80 90 85 40 45 43 24 M 78 75.73 85.96 80.845 7.53 2.1 23.2 74.8 MVB y = 122.88ln(x) - 305.91 226 241 234 169 181 175 113 121 117 56 60 58 25 M 79 36.51 51.28 43.895 8.86 1.9 34.7 63.4 HVB-A y = 78.864ln(x) - 193.00 91 118 105 68 88 79 45 59 53 23 29 26 26 M 80 9.08 22.29 15.685 6.68 2.5 33.8 63.6 HVB-A y = 78.864ln(x) - 193.00 (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) 27 M 81 90.86 106.31 98.585 8.27 1.9 34.4 63.7 HVB-A y = 78.864ln(x) - 193.00 163 175 169 122 131 127 81 88 85 41 44 42 28 M 82 62.87 72.99 67.93 5.18 1.7 33.8 64.5 HVB-A y = 78.864ln(x) - 193.00 134 145 140 100 109 105 67 73 70 33 36 35 29 M 83 25.38 34.13 29.755 5.82 1.9 33.9 64.2 HVB-A y = 78.864ln(x) - 193.00 (1) 85 (1) (1) 64 (1) (1) 43 (1) (1) 21 (1) 30 M 85 82.58 93.29 87.935 5.13 2.0 34.8 63.1 HVB-A y = 78.864ln(x) - 193.00 155 165 160 116 124 120 78 82 80 39 41 40 31 M 86 56.68 65.15 60.915 3.66 1.9 34.1 64.0 HVB-A y = 78.864ln(x) - 193.00 125 136 131 94 102 98 63 68 66 31 34 33 32 M 87 22 35.81 28.905 8.03 2.2 34.1 63.7 HVB-A y = 78.864ln(x) - 193.00 (1) 89 (1) (1) 67 (1) (1) 45 (1) (1) 22 (1) 33 M 88 4.2 8.9 6.55 4.7 2.1 23.2 74.8 MVB y = 122.88ln(x) - 305.91 (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) 196 S e q u e n c e N e t t C o a l T h i c k n e s s ( m ) M o i s t u r e ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) M i n i m u m M a x i m u m A v e r a g e M i n i m u m M a x i m u m A v e r a g e M i n i m u m M a x i m u m A v e r a g e M i n i m u m M a x i m u m A v e r a g e Coal Interval Coal Quality Gas Content Calculated from Eddy, et al. (1982) Trend Line Equations (scf/T) Ash-Free Full Saturation (100%) 75% Saturation 50% Saturation 25% SaturationBorehole ID / Eddy, et al. (1982) Trend Field Name\ Sample Coal Line Equation From (m) To (m) Mid-Point Rank (m) Code 34 M 89 94.76 107.99 101.375 4 2.5 33.7 63.8 HVB-A y = 78.864ln(x) - 193.00 166 176 171 124 132 128 83 88 86 41 44 43 35 M 90 75.7 86.42 81.06 4.4 2.2 34.4 63.4 HVB-A y = 78.864ln(x) - 193.00 148 159 154 111 119 115 74 79 77 37 40 38 36 M 91 56 65.09 60.545 3.02 2.0 34.4 63.6 HVB-A y = 78.864ln(x) - 193.00 124 136 131 93 102 98 62 68 65 31 34 33 37 M 92 20.31 37.26 28.785 9.12 2.2 34.5 63.3 HVB-A y = 78.864ln(x) - 193.00 (1) 92 (1) (1) 69 (1) (1) 46 (1) (1) 23 (1) 38 M 94 74.04 83.46 78.75 4.7 2.0 34.5 63.5 HVB-A y = 78.864ln(x) - 193.00 146 156 151 110 117 114 73 78 76 37 39 38 39 M 95 43.11 57.73 50.42 8.74 2.1 34.7 63.2 HVB-A y = 78.864ln(x) - 193.00 104 127 116 78 95 87 52 63 58 26 32 29 40 1740 156.38 168.9 162.64 12.52 1.7 25.5 72.8 MVB y = 122.88ln(x) - 305.91 315 324 320 236 243 240 157 162 160 79 81 80 41 1741 179.2 187.3 183.25 8.1 1.8 26.3 71.9 MVB y = 122.88ln(x) - 305.91 332 337 334 249 253 251 166 169 167 83 84 84 42 1742 164.26 171.9 168.08 7.64 2.2 27.8 70.0 MVB y = 122.88ln(x) - 305.91 321 327 324 241 245 243 160 163 162 80 82 81 43 1743 249.92 256.6 253.26 6.68 1.8 25.4 72.8 MVB y = 122.88ln(x) - 305.91 373 376 374 279 282 281 186 188 187 93 94 94 44 1744 255.48 262.8 259.14 7.32 1.2 25.4 73.4 MVB y = 122.88ln(x) - 305.91 375 379 377 281 284 283 188 189 188 94 95 94 45 1745 251.76 257.7 254.73 5.94 1.2 25.4 73.4 MVB y = 122.88ln(x) - 305.91 373 376 375 280 282 281 187 188 187 93 94 94 46 1746 206.97 213.5 210.235 6.53 1.7 25.8 72.5 MVB y = 122.88ln(x) - 305.91 349 353 351 262 265 263 175 177 176 87 88 88 47 1747 292.29 301.2 296.745 8.91 1.9 26.4 71.7 MVB y = 122.88ln(x) - 305.91 392 395 394 294 297 295 196 198 197 98 99 98 48 1748 271.14 278.2 274.67 7.06 2.3 26.5 71.2 MVB y = 122.88ln(x) - 305.91 383 386 384 287 289 288 191 193 192 96 96 96 49 1749 229.92 239.6 234.76 9.68 1.2 25.4 73.4 MVB y = 122.88ln(x) - 305.91 362 367 365 272 276 274 181 184 182 91 92 91 50 1750 282.29 287.7 284.995 5.41 1.4 25.1 73.5 MVB y = 122.88ln(x) - 305.91 387 390 389 291 292 291 194 195 194 97 97 97 51 1751 285.21 295.8 290.505 10.59 2.1 27.3 70.6 MVB y = 122.88ln(x) - 305.91 389 393 391 292 295 293 194 197 196 97 98 98 52 1752 306.92 318.2 312.56 11.28 1.2 25.4 73.4 MVB y = 122.88ln(x) - 305.91 398 402 400 298 302 300 199 201 200 99 101 100 53 1753 2.1 23.2 74.8 MVB y = 122.88ln(x) - 305.91 (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) 54 1754 187.34 196 191.67 8.66 1.2 25.4 73.4 MVB y = 122.88ln(x) - 305.91 337 343 340 253 257 255 169 171 170 84 86 85 55 1755 173.98 180.1 177.04 6.12 1.6 25.5 72.9 MVB y = 122.88ln(x) - 305.91 328 332 330 246 249 248 164 166 165 82 83 83 56 1756 274.18 283.3 278.74 9.12 1.2 25.4 73.4 MVB y = 122.88ln(x) - 305.91 384 388 386 288 291 289 192 194 193 96 97 96 57 1757 290.1 296.9 293.5 6.8 2.2 26.2 71.5 MVB y = 122.88ln(x) - 305.91 391 394 392 293 295 294 195 197 196 98 98 98 58 1758 326.76 335.6 331.18 8.84 1.5 26.9 71.6 MVB y = 122.88ln(x) - 305.91 405 409 407 304 307 305 203 204 204 101 102 102 59 1759 302.67 311.3 306.985 8.63 1.5 27.5 71.0 MVB y = 122.88ln(x) - 305.91 396 400 398 297 300 298 198 200 199 99 100 99 60 1760 321.99 332.2 327.095 10.21 1.4 25.5 73.1 MVB y = 122.88ln(x) - 305.91 404 407 406 303 306 304 202 204 203 101 102 101 61 1761 297.95 306.2 302.075 8.25 1.4 25.2 73.4 MVB y = 122.88ln(x) - 305.91 394 397 396 296 298 297 197 199 198 99 99 99 62 1763 2.1 23.2 74.8 MVB y = 122.88ln(x) - 305.91 (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) 63 1764A 313.47 325.47 319.47 11.73 1.0 28.7 70.3 MVB y = 122.88ln(x) - 305.91 400 405 403 300 304 302 200 202 201 100 101 101 64 E 1 65 E 2 34.89 47.39 41.14 12.5 1.3 24.9 73.8 MVB y = 122.88ln(x) - 305.91 131 168 151 98 126 113 65 84 75 33 42 38 66 E 3 33 43.38 38.19 10.38 1.2 20.1 78.8 LVB y = 141.59ln(x) - 316.94 178 217 199 134 163 149 89 108 99 45 54 50 67 E 3A 33.7 44.53 39.115 10.83 1.4 23.0 75.7 MVB y = 122.88ln(x) - 305.91 126 161 145 95 120 108 63 80 72 32 40 36 197 S e q u e n c e N e t t C o a l T h i c k n e s s ( m ) M o i s t u r e ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) M i n i m u m M a x i m u m A v e r a g e M i n i m u m M a x i m u m A v e r a g e M i n i m u m M a x i m u m A v e r a g e M i n i m u m M a x i m u m A v e r a g e Coal Interval Coal Quality Gas Content Calculated from Eddy, et al. (1982) Trend Line Equations (scf/T) Ash-Free Full Saturation (100%) 75% Saturation 50% Saturation 25% SaturationBorehole ID / Eddy, et al. (1982) Trend Field Name\ Sample Coal Line Equation From (m) To (m) Mid-Point Rank (m) Code 68 E 4 35.25 46.18 40.715 10.93 0.9 23.9 75.2 MVB y = 122.88ln(x) - 305.91 132 165 150 99 124 112 66 83 75 33 41 37 69 E 5 49.68 61.77 55.725 12.09 1.1 23.6 75.3 MVB y = 122.88ln(x) - 305.91 174 201 188 131 151 141 87 100 94 44 50 47 70 E 6 486.16 497.13 491.645 10.97 1.4 19.5 79.1 LVB y = 141.59ln(x) - 316.94 559 562 561 419 422 420 280 281 280 140 141 140 71 E 6 486.16 497.13 491.645 10.97 1.5 20.8 77.7 LVB y = 141.59ln(x) - 316.94 559 562 561 419 422 420 280 281 280 140 141 140 72 E 7 547.62 559.6 553.61 11.98 1.4 21.9 76.7 MVB y = 122.88ln(x) - 305.91 469 472 470 352 354 353 234 236 235 117 118 118 73 E 8 69.11 80.77 74.94 11.66 1.0 26.5 72.6 MVB y = 122.88ln(x) - 305.91 215 234 225 161 175 168 107 117 112 54 58 56 74 E 8 69.11 80.77 74.94 11.66 1.6 23.4 74.9 MVB y = 122.88ln(x) - 305.91 215 234 225 161 175 168 107 117 112 54 58 56 75 E 8 69.11 80.77 74.94 11.66 1.3 26.4 72.3 MVB y = 122.88ln(x) - 305.91 215 234 225 161 175 168 107 117 112 54 58 56 76 E 9 103.33 115.52 109.425 12.19 1.4 25.3 73.3 MVB y = 122.88ln(x) - 305.91 264 278 271 198 208 203 132 139 136 66 69 68 77 E 9A 54.86 64.26 59.56 9.4 0.3 28.0 71.6 MVB y = 122.88ln(x) - 305.91 186 206 196 140 154 147 93 103 98 47 51 49 78 E 9A 54.86 64.26 59.56 9.4 1.4 24.2 74.5 MVB y = 122.88ln(x) - 305.91 186 206 196 140 154 147 93 103 98 47 51 49 79 E 9A 54.86 64.26 59.56 9.4 1.4 21.8 76.8 MVB y = 122.88ln(x) - 305.91 186 206 196 140 154 147 93 103 98 47 51 49 80 E 10 34.16 46.33 40.245 12.17 1.1 24.2 74.7 MVB y = 122.88ln(x) - 305.91 128 165 148 96 124 111 64 83 74 32 41 37 81 E 12 47.72 57.06 52.39 9.34 1.3 26.7 72.0 MVB y = 122.88ln(x) - 305.91 169 191 181 127 143 135 85 96 90 42 48 45 82 E 12 47.72 57.06 52.39 9.34 1.0 24.9 74.1 MVB y = 122.88ln(x) - 305.91 169 191 181 127 143 135 85 96 90 42 48 45 83 E 13 32.31 40.81 36.56 8.5 2.0 24.2 73.8 MVB y = 122.88ln(x) - 305.91 121 150 136 91 112 102 61 75 68 30 37 34 84 E 15 346.4 359.66 353.03 13.26 1.8 18.7 79.5 LVB y = 141.59ln(x) - 316.94 511 516 514 383 387 385 256 258 257 128 129 128 85 E 15 346.4 359.66 353.03 13.26 2.0 22.4 75.6 MVB y = 122.88ln(x) - 305.91 413 417 415 309 313 311 206 209 207 103 104 104 86 E 16A 49.07 62 55.535 12.93 1.5 24.1 74.4 MVB y = 122.88ln(x) - 305.91 172 201 188 129 151 141 86 101 94 43 50 47 87 E 16A 49.07 62 55.535 12.93 1.5 23.5 75.0 MVB y = 122.88ln(x) - 305.91 172 201 188 129 151 141 86 101 94 43 50 47 88 E 16A 49.07 62 55.535 12.93 1.1 26.5 72.4 MVB y = 122.88ln(x) - 305.91 172 201 188 129 151 141 86 101 94 43 50 47 89 E 17 90 E 17A 49.53 59.61 54.57 10.08 1.2 23.9 74.8 MVB y = 122.88ln(x) - 305.91 174 196 186 130 147 139 87 98 93 43 49 46 91 E 18 57.61 70.02 63.815 12.41 2.0 20.5 77.6 LVB y = 141.59ln(x) - 316.94 257 285 272 193 213 204 129 142 136 64 71 68 92 E 18 57.61 70.02 63.815 12.41 1.9 20.4 77.7 LVB y = 141.59ln(x) - 316.94 257 285 272 193 213 204 129 142 136 64 71 68 93 E 18 57.61 70.02 63.815 12.41 1.9 21.9 76.3 MVB y = 122.88ln(x) - 305.91 192 216 205 144 162 154 96 108 102 48 54 51 94 E 19 95 E 19A 39.01 43.84 41.425 4.83 7.8 16.9 75.3 MVB y = 122.88ln(x) - 305.91 144 159 152 108 119 114 72 79 76 36 40 38 96 E 19B 39.01 48.87 43.94 9.86 1.0 25.3 73.7 MVB y = 122.88ln(x) - 305.91 144 172 159 108 129 119 72 86 79 36 43 40 97 E 19C 41.15 53.04 47.095 11.89 1.9 23.0 75.1 MVB y = 122.88ln(x) - 305.91 151 182 167 113 137 126 75 91 84 38 46 42 98 E 19C 41.15 53.04 47.095 11.89 1.6 23.9 74.5 MVB y = 122.88ln(x) - 305.91 151 182 167 113 137 126 75 91 84 38 46 42 99 E 19C 41.15 53.04 47.095 11.89 1.2 28.2 70.6 MVB y = 122.88ln(x) - 305.91 151 182 167 113 137 126 75 91 84 38 46 42 100 E 20 101 E 21 171 181.98 176.49 10.98 0.6 22.2 77.2 LVB y = 141.59ln(x) - 316.94 411 420 416 308 315 312 206 210 208 103 105 104 198 S e q u e n c e N e t t C o a l T h i c k n e s s ( m ) M o i s t u r e ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) M i n i m u m M a x i m u m A v e r a g e M i n i m u m M a x i m u m A v e r a g e M i n i m u m M a x i m u m A v e r a g e M i n i m u m M a x i m u m A v e r a g e Coal Interval Coal Quality Gas Content Calculated from Eddy, et al. (1982) Trend Line Equations (scf/T) Ash-Free Full Saturation (100%) 75% Saturation 50% Saturation 25% SaturationBorehole ID / Eddy, et al. (1982) Trend Field Name\ Sample Coal Line Equation From (m) To (m) Mid-Point Rank (m) Code 102 E 22 103 E 24 55.44 65.84 60.64 10.4 0.3 25.4 74.4 MVB y = 122.88ln(x) - 305.91 187 209 199 141 156 149 94 104 99 47 52 50 104 E 24 55.44 65.84 60.64 10.4 1.7 22.8 75.5 MVB y = 122.88ln(x) - 305.91 187 209 199 141 156 149 94 104 99 47 52 50 105 E 25 55.91 67.57 61.74 11.66 1.4 20.6 78.0 LVB y = 141.59ln(x) - 316.94 253 280 267 190 210 200 126 140 133 63 70 67 106 E 26 94.14 104.1 99.12 9.87 1.7 21.3 77.0 MVB y = 122.88ln(x) - 305.91 253 265 259 189 199 194 126 132 129 63 66 65 107 E 27 270.05 281.18 275.615 11.13 1.2 21.4 77.4 LVB y = 141.59ln(x) - 316.94 476 481 479 357 361 359 238 241 239 119 120 120 108 E 28 109 E 29 100.58 114.66 107.62 14.08 1.0 20.8 78.2 LVB y = 141.59ln(x) - 316.94 336 354 346 252 266 259 168 177 173 84 89 86 110 E 29 100.58 114.66 107.62 14.08 0.7 23.6 75.7 MVB y = 122.88ln(x) - 305.91 261 277 269 196 208 202 130 138 134 65 69 67 111 E 30 53.34 61.57 57.455 8.23 0.9 24.3 74.7 MVB y = 122.88ln(x) - 305.91 183 200 192 137 150 144 91 100 96 46 50 48 112 E 30 53.34 61.57 57.455 8.23 0.8 22.5 76.6 MVB y = 122.88ln(x) - 305.91 183 200 192 137 150 144 91 100 96 46 50 48 113 E 31 161.39 170.38 165.885 8.99 1.0 26.6 72.5 MVB y = 122.88ln(x) - 305.91 319 325 322 239 244 242 159 163 161 80 81 81 114 E 32 105.77 114.6 110.185 8.83 0.8 19.5 79.7 LVB y = 141.59ln(x) - 316.94 343 354 349 257 266 262 172 177 174 86 89 87 115 E 32 105.77 114.6 110.185 8.83 0.9 23.1 76.0 MVB y = 122.88ln(x) - 305.91 267 277 272 200 208 204 133 138 136 67 69 68 116 E 33 89.97 100.35 95.16 10.38 1.5 23.7 74.8 MVB y = 122.88ln(x) - 305.91 247 260 254 185 195 190 123 130 127 62 65 63 117 E 33 89.97 100.35 95.16 10.38 1.3 22.7 76.0 MVB y = 122.88ln(x) - 305.91 247 260 254 185 195 190 123 130 127 62 65 63 118 E 34 161.08 173.35 167.215 12.27 0.3 21.4 78.3 LVB y = 141.59ln(x) - 316.94 403 413 408 302 310 306 201 207 204 101 103 102 119 E 34 161.08 173.35 167.215 12.27 1.1 20.9 78.0 LVB y = 141.59ln(x) - 316.94 403 413 408 302 310 306 201 207 204 101 103 102 120 E 34 161.08 173.35 167.215 12.27 0.7 27.1 72.4 MVB y = 122.88ln(x) - 305.91 319 328 323 239 246 242 159 164 162 80 82 81 121 E 35 170.69 180.74 175.715 10.05 1.0 23.0 76.0 MVB y = 122.88ln(x) - 305.91 326 333 329 244 250 247 163 166 165 81 83 82 122 E 36 204.08 212.58 208.33 8.5 1.8 23.6 74.6 MVB y = 122.88ln(x) - 305.91 348 353 350 261 264 263 174 176 175 87 88 88 123 E 37 256.64 265.18 260.91 8.54 1.1 22.3 76.5 MVB y = 122.88ln(x) - 305.91 376 380 378 282 285 283 188 190 189 94 95 94 124 E 38 329.79 332.38 331.085 2.59 1.1 22.3 76.5 MVB y = 122.88ln(x) - 305.91 407 408 407 305 306 305 203 204 204 102 102 102 125 E 39 53.04 66.55 59.795 13.51 1.6 22.4 76.0 MVB y = 122.88ln(x) - 305.91 182 210 197 137 157 148 91 105 98 46 52 49 126 E 40 37.8 50.9 44.35 13.1 1.3 23.8 74.9 MVB y = 122.88ln(x) - 305.91 140 177 160 105 133 120 70 88 80 35 44 40 127 E 41 43.93 55.93 49.93 12 1.5 22.7 75.8 MVB y = 122.88ln(x) - 305.91 159 189 175 119 141 131 79 94 87 40 47 44 128 E 42 52.58 64.58 58.58 12 1.5 22.7 75.9 MVB y = 122.88ln(x) - 305.91 181 206 194 136 155 146 90 103 97 45 52 49 129 E 43 55.56 67.56 61.56 12 1.5 23.0 75.5 MVB y = 122.88ln(x) - 305.91 188 212 200 141 159 150 94 106 100 47 53 50 130 E 44 49.99 53.77 51.88 3.78 1.7 14.7 83.6 LVB y = 141.59ln(x) - 316.94 237 247 242 178 185 182 118 124 121 59 62 61 131 E 45 8.53 20.37 14.45 11.84 1.5 25.2 73.3 MVB y = 122.88ln(x) - 305.91 (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) 132 E 46 31.23 41.8 36.515 10.57 0.7 25.4 73.8 MVB y = 122.88ln(x) - 305.91 117 153 136 88 115 102 58 76 68 29 38 34 133 E 47 37.19 48.52 42.855 11.33 1.8 24.8 73.4 MVB y = 122.88ln(x) - 305.91 138 171 156 104 128 117 69 86 78 35 43 39 134 E 48 42.98 56.69 49.835 13.71 1.6 23.9 74.5 MVB y = 122.88ln(x) - 305.91 156 190 174 117 143 131 78 95 87 39 48 44 135 E 49 50.9 60.86 55.88 9.96 1.5 26.1 72.4 MVB y = 122.88ln(x) - 305.91 177 199 188 133 149 141 88 99 94 44 50 47 199 S e q u e n c e N e t t C o a l T h i c k n e s s ( m ) M o i s t u r e ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) M i n i m u m M a x i m u m A v e r a g e M i n i m u m M a x i m u m A v e r a g e M i n i m u m M a x i m u m A v e r a g e M i n i m u m M a x i m u m A v e r a g e Coal Interval Coal Quality Gas Content Calculated from Eddy, et al. (1982) Trend Line Equations (scf/T) Ash-Free Full Saturation (100%) 75% Saturation 50% Saturation 25% SaturationBorehole ID / Eddy, et al. (1982) Trend Field Name\ Sample Coal Line Equation From (m) To (m) Mid-Point Rank (m) Code 136 E 50 49.02 61.23 55.125 12.21 1.6 25.2 73.2 MVB y = 122.88ln(x) - 305.91 172 200 187 129 150 140 86 100 93 43 50 47 137 E 51 33.51 46.8 40.155 13.29 1.6 24.7 73.8 MVB y = 122.88ln(x) - 305.91 126 167 148 94 125 111 63 83 74 31 42 37 138 E 52 45.09 59.21 52.15 14.12 1.2 25.4 73.5 MVB y = 122.88ln(x) - 305.91 162 196 180 122 147 135 81 98 90 41 49 45 139 E 53 42.67 52.88 47.775 10.21 1.5 23.4 75.1 MVB y = 122.88ln(x) - 305.91 155 182 169 116 136 127 78 91 85 39 45 42 140 E 54 81.08 92.81 86.945 11.73 0.5 25.3 74.2 MVB y = 122.88ln(x) - 305.91 234 251 243 176 188 182 117 125 121 59 63 61 141 E 55 102.11 115.66 108.885 13.55 1.4 23.8 74.8 MVB y = 122.88ln(x) - 305.91 263 278 270 197 208 203 131 139 135 66 69 68 142 E 56 39.93 51.77 45.85 11.84 1.4 23.8 74.8 MVB y = 122.88ln(x) - 305.91 147 179 164 110 134 123 74 90 82 37 45 41 143 E 57 137.33 147.68 142.505 10.35 1.2 23.2 75.6 MVB y = 122.88ln(x) - 305.91 299 308 303 224 231 228 149 154 152 75 77 76 144 E 58 160.43 172.73 166.58 12.3 1.1 23.2 75.7 MVB y = 122.88ln(x) - 305.91 318 327 323 239 245 242 159 164 161 80 82 81 145 E 59 35.29 51.06 43.175 15.77 1.8 24.4 73.8 MVB y = 122.88ln(x) - 305.91 132 177 157 99 133 118 66 89 78 33 44 39 146 E 60 188.06 199.17 193.615 11.11 0.9 25.7 73.5 MVB y = 122.88ln(x) - 305.91 338 345 341 253 258 256 169 172 171 84 86 85 147 E 61 185.17 200.67 192.92 15.5 1.4 24.5 74.2 MVB y = 122.88ln(x) - 305.91 336 346 341 252 259 256 168 173 170 84 86 85 148 E 62 46.35 61.73 54.04 15.38 1.9 24.1 74.0 MVB y = 122.88ln(x) - 305.91 165 201 184 124 151 138 83 100 92 41 50 46 149 E 63 210.64 222.73 216.685 12.09 1.5 24.1 74.4 MVB y = 122.88ln(x) - 305.91 352 358 355 264 269 266 176 179 177 88 90 89 150 E 64 210.08 230.42 220.25 20.34 1.1 22.3 76.5 MVB y = 122.88ln(x) - 305.91 351 363 357 263 272 268 176 181 178 88 91 89 151 E 65 89.81 99.16 94.485 9.98 1.5 22.6 75.9 MVB y = 122.88ln(x) - 305.91 247 259 253 185 194 190 123 129 127 62 65 63 152 E 66 94.67 106.96 100.815 12.29 0.8 24.3 75.2 MVB y = 122.88ln(x) - 305.91 253 268 261 190 201 196 127 134 130 63 67 65 153 E 66A 94.59 105.73 100.16 11.14 1.4 23.1 75.6 MVB y = 122.88ln(x) - 305.91 253 267 260 190 200 195 127 133 130 63 67 65 154 E 67 76.88 89.99 83.435 13.11 1.8 22.7 75.5 MVB y = 122.88ln(x) - 305.91 228 247 238 171 185 178 114 124 119 57 62 59 155 E 68 74.19 87.99 81.09 13.8 1.5 23.6 74.9 MVB y = 122.88ln(x) - 305.91 223 244 234 167 183 176 112 122 117 56 61 59 156 E 69 140.85 153.54 147.195 12.69 1.2 21.3 77.5 LVB y = 141.59ln(x) - 316.94 384 396 390 288 297 292 192 198 195 96 99 97 157 E 70 150.27 160.67 155.47 10.4 1.0 23.8 75.2 MVB y = 122.88ln(x) - 305.91 310 318 314 233 239 236 155 159 157 78 80 79 158 E 71 151.91 161.46 156.685 9.55 1.2 24.0 74.9 MVB y = 122.88ln(x) - 305.91 311 319 315 234 239 236 156 159 158 78 80 79 159 E 72 144.13 152.9 148.515 8.77 1.0 23.0 76.0 MVB y = 122.88ln(x) - 305.91 305 312 309 229 234 231 152 156 154 76 78 77 160 E 73 203.05 214.63 208.84 11.58 1.3 21.8 76.9 MVB y = 122.88ln(x) - 305.91 347 354 350 260 265 263 174 177 175 87 88 88 161 E 74 183.99 194.54 189.265 10.55 1.1 22.6 76.3 MVB y = 122.88ln(x) - 305.91 335 342 338 251 256 254 167 171 169 84 85 85 162 E 75 189.2 197.66 193.43 8.46 1.3 24.8 73.9 MVB y = 122.88ln(x) - 305.91 338 344 341 254 258 256 169 172 171 85 86 85 163 E 76 176.02 180.12 178.07 4.1 0.7 22.3 77.0 MVB y = 122.88ln(x) - 305.91 329 332 331 247 249 248 165 166 165 82 83 83 164 E 77 243.75 254.66 249.205 10.91 1.2 20.8 77.9 LVB y = 141.59ln(x) - 316.94 461 467 464 346 351 348 231 234 232 115 117 116 165 E 78 226.49 237.38 231.935 10.89 1.2 21.5 77.3 LVB y = 141.59ln(x) - 316.94 451 458 454 338 343 341 225 229 227 113 114 114 166 E 79 226.1 235.93 231.015 9.83 1.0 22.2 76.8 MVB y = 122.88ln(x) - 305.91 360 365 363 270 274 272 180 183 181 90 91 91 167 E 80B 246.14 255.4 250.77 9.26 1.2 22.5 76.2 MVB y = 122.88ln(x) - 305.91 371 375 373 278 281 280 185 188 186 93 94 93 168 E 81 241.28 249.18 245.23 7.82 1.0 21.1 77.9 LVB y = 141.59ln(x) - 316.94 460 464 462 345 348 347 230 232 231 115 116 116 169 E 82 325.23 333.69 329.46 8.46 1.2 22.7 76.1 MVB y = 122.88ln(x) - 305.91 405 408 406 304 306 305 202 204 203 101 102 102 200 S e q u e n c e N e t t C o a l T h i c k n e s s ( m ) M o i s t u r e ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) M i n i m u m M a x i m u m A v e r a g e M i n i m u m M a x i m u m A v e r a g e M i n i m u m M a x i m u m A v e r a g e M i n i m u m M a x i m u m A v e r a g e Coal Interval Coal Quality Gas Content Calculated from Eddy, et al. (1982) Trend Line Equations (scf/T) Ash-Free Full Saturation (100%) 75% Saturation 50% Saturation 25% SaturationBorehole ID / Eddy, et al. (1982) Trend Field Name\ Sample Coal Line Equation From (m) To (m) Mid-Point Rank (m) Code 170 E 83 314.62 323.22 318.92 8.6 1.1 22.2 76.6 MVB y = 122.88ln(x) - 305.91 401 404 402 301 303 302 200 202 201 100 101 101 171 E 84 261.14 269.66 265.4 8.52 1.3 21.9 76.8 MVB y = 122.88ln(x) - 305.91 378 382 380 283 286 285 189 191 190 94 95 95 172 E 85 315.49 323.26 319.375 7.77 1.1 22.1 76.8 MVB y = 122.88ln(x) - 305.91 401 404 403 301 303 302 201 202 201 100 101 101 173 E 87 6.08 10.5 8.29 4.42 1.4 24.2 74.5 MVB y = 122.88ln(x) - 305.91 (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) 174 E 88 53.54 63.85 58.695 10.31 1.4 24.2 74.5 MVB y = 122.88ln(x) - 305.91 183 205 195 137 154 146 92 102 97 46 51 49 175 E 89 48.46 52.94 50.7 4.48 1.4 24.2 74.5 MVB y = 122.88ln(x) - 305.91 171 182 177 128 136 132 85 91 88 43 45 44 176 E 90 38.6 48.87 43.735 10.27 1.2 23.2 75.6 MVB y = 122.88ln(x) - 305.91 143 172 158 107 129 119 72 86 79 36 43 40 177 E 91 49.38 61.1 55.24 11.72 1.0 24.3 74.7 MVB y = 122.88ln(x) - 305.91 173 199 187 130 150 140 87 100 94 43 50 47 178 E 92 47.5 59.08 53.29 11.58 1.4 24.2 74.5 MVB y = 122.88ln(x) - 305.91 168 195 183 126 146 137 84 98 91 42 49 46 179 E 93 64.22 64.22 1.4 24.2 74.5 MVB y = 122.88ln(x) - 305.91 206 (1) 206 154 (1) 154 103 (1) 103 51 (1) 51 180 E 94 58.92 69.31 64.115 10.39 1.4 24.2 74.5 MVB y = 122.88ln(x) - 305.91 195 215 205 146 161 154 97 107 103 49 54 51 181 E 96 182 E 97 183 E 98 110.5 121.6 116.05 11.1 1.1 22.3 76.5 MVB y = 122.88ln(x) - 305.91 272 284 278 204 213 209 136 142 139 68 71 70 184 E 99 218.85 227.13 222.99 8.28 1.1 22.3 76.5 MVB y = 122.88ln(x) - 305.91 356 361 359 267 271 269 178 180 179 89 90 90 185 E 101 229.08 238.44 233.76 9.36 1.1 22.3 76.5 MVB y = 122.88ln(x) - 305.91 362 367 364 271 275 273 181 183 182 90 92 91 186 E 102 201.8 210.6 206.2 8.8 1.1 22.3 76.5 MVB y = 122.88ln(x) - 305.91 346 351 349 260 264 262 173 176 174 87 88 87 187 E 103 93.46 101.82 97.64 8.36 1.4 24.2 74.5 MVB y = 122.88ln(x) - 305.91 252 262 257 189 197 193 126 131 129 63 66 64 188 E 104 119.41 125.83 122.62 6.42 1.1 22.3 76.5 MVB y = 122.88ln(x) - 305.91 282 288 285 211 216 214 141 144 143 70 72 71 189 LBW 1 11.12 13.14 12.13 2.02 1.8 41.5 56.7 HVB-B y = 52.803ln(x) - 141.04 (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) 190 LBW 1 16.17 20.23 18.2 3.73 1.7 38.1 60.2 HVB-B y = 52.803ln(x) - 141.04 (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) 191 LBW 1 28.82 43.33 36.075 1.5 32.2 66.3 192 LBW 1 10.53 1.4 33.4 65.2 HVB-A y = 78.864ln(x) - 193.00 (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) 193 LBW 2 84.71 88.66 86.685 2.8 1.8 39.7 58.2 HVB-B y = 52.803ln(x) - 141.04 93 96 95 70 72 71 47 48 47 23 24 24 194 LBW 2 95.94 111.56 103.75 1.5 32.2 66.3 195 LBW 2 13.57 1.4 28.8 69.7 MVB y = 122.88ln(x) - 305.91 (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) 196 LBW 4 41.51 43.51 42.51 2 1.5 38.2 60.2 HVB-B y = 52.803ln(x) - 141.04 56 58 57 42 44 43 28 29 28 14 15 14 197 LBW 4 51.9 70.13 61.015 17.92 1.3 30.5 68.1 HVB-A y = 78.864ln(x) - 193.00 118 142 131 89 107 98 59 71 66 30 36 33 198 LBW 5 32.76 36.41 34.585 3.26 1.7 39.5 59.0 HVB-B y = 52.803ln(x) - 141.04 43 49 46 32 37 35 22 24 23 11 12 12 199 LBW 5 40.53 56.83 48.68 16.2 1.2 33.0 65.7 HVB-A y = 78.864ln(x) - 193.00 99 126 113 74 94 85 49 63 57 25 31 28 200 LBW 6 65.61 74.1 69.855 9.09 1.5 32.2 66.3 201 LBW 6 15 98 56.5 7.96 1.6 32.9 55.1 HVB-B y = 52.803ln(x) - 141.04 (1) 101 72 (1) 76 54 (1) 51 36 (1) 25 18 202 LBW 6 83.56 92.7 88.13 8.65 1.3 33.6 65.0 HVB-A y = 78.864ln(x) - 193.00 156 164 160 117 123 120 78 82 80 39 41 40 203 LBW 7 55.05 58.99 57.02 3.69 1.8 39.3 59.1 HVB-B y = 52.803ln(x) - 141.04 71 74 72 53 56 54 35 37 36 18 19 18 201 S e q u e n c e N e t t C o a l T h i c k n e s s ( m ) M o i s t u r e ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) M i n i m u m M a x i m u m A v e r a g e M i n i m u m M a x i m u m A v e r a g e M i n i m u m M a x i m u m A v e r a g e M i n i m u m M a x i m u m A v e r a g e Coal Interval Coal Quality Gas Content Calculated from Eddy, et al. (1982) Trend Line Equations (scf/T) Ash-Free Full Saturation (100%) 75% Saturation 50% Saturation 25% SaturationBorehole ID / Eddy, et al. (1982) Trend Field Name\ Sample Coal Line Equation From (m) To (m) Mid-Point Rank (m) Code 204 LBW 7 64.65 82.28 73.465 15.68 1.5 34.2 64.3 HVB-A y = 78.864ln(x) - 193.00 136 155 146 102 116 109 68 77 73 34 39 36 205 LBW 8 25.64 29.43 27.535 3.43 1.4 36.3 62.3 HVB-A y = 78.864ln(x) - 193.00 (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) 206 LBW 8 34.9 46.35 40.625 9.31 1.2 32.6 66.2 HVB-A y = 78.864ln(x) - 193.00 87 110 99 65 82 74 44 55 50 22 27 25 207 LBW 9 14.81 16.81 15.81 1.91 1.7 38.8 59.5 HVB-B y = 52.803ln(x) - 141.04 (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) 208 LBW 9 26.6 34.58 30.59 7.98 1.3 32.9 65.7 HVB-A y = 78.864ln(x) - 193.00 (1) 86 77 (1) 65 58 (1) 43 38 (1) 22 19 209 LBW 10 63.13 67.19 65.16 3.74 1.8 33.8 56.7 HVB-B y = 52.803ln(x) - 141.04 78 81 80 58 61 60 39 41 40 19 20 20 210 LBW 10 73.22 84.3 78.76 10.98 1.3 30.9 67.8 HVB-A y = 78.864ln(x) - 193.00 146 157 151 109 118 114 73 78 76 36 39 38 211 LBW 11 32.11 36.16 34.135 1.7 2.6 39.1 60.9 HVB-B y = 52.803ln(x) - 141.04 42 48 45 32 36 34 21 24 23 11 12 11 212 LBW 11 44.04 57.16 50.6 13.12 1.5 32.2 66.3 213 LBW 11 12.3 3.6 33.6 62.9 HVB-A y = 78.864ln(x) - 193.00 (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) 214 LBW 12 39.86 50.87 45.365 6.13 3.7 39.7 56.6 HVB-B y = 52.803ln(x) - 141.04 54 66 60 40 50 45 27 33 30 13 17 15 215 LBW 12 66.3 79.84 73.07 12.57 2.6 26.8 70.6 MVB y = 122.88ln(x) - 305.91 209 232 221 157 174 166 105 116 111 52 58 55 216 LBW 13 97.77 102 99.885 4.04 1.3 30.8 67.9 HVB-A y = 78.864ln(x) - 193.00 168 172 170 126 129 128 84 86 85 42 43 43 217 S 1 96.01 113.08 104.545 17.07 5.1 33.1 61.8 HVB-B y = 52.803ln(x) - 141.04 100 109 104 75 81 78 50 54 52 25 27 26 218 S 2 63.93 77.62 70.775 13.69 5.7 28.0 66.3 HVB-A y = 78.864ln(x) - 193.00 135 150 143 101 113 107 67 75 71 34 38 36 219 S 3 6.1 15.24 10.67 9.14 6.1 28.3 65.6 HVB-A y = 78.864ln(x) - 193.00 (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) 220 S 5 90.22 107.29 98.755 17.07 6.3 25.4 68.3 HVB-A y = 78.864ln(x) - 193.00 162 176 169 122 132 127 81 88 85 41 44 42 221 S 18 151.79 160.55 156.17 8.76 3.5 33.0 63.5 HVB-A y = 78.864ln(x) - 193.00 203 208 205 152 156 154 102 104 103 51 52 51 222 S 25 147.51 159.4 153.455 11.89 4.3 28.7 67.0 HVB-A y = 78.864ln(x) - 193.00 201 207 204 151 155 153 100 103 102 50 52 51 223 S 26 11.27 21.96 16.615 10.69 4.9 25.3 69.8 MVB y = 122.88ln(x) - 305.91 (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) 224 S 27 85.8 97.92 91.86 12.12 4.4 27.2 68.4 HVB-A y = 78.864ln(x) - 193.00 158 169 163 119 126 123 79 84 82 40 42 41 225 S 29 70.71 80.95 75.83 10.24 4.7 27.7 67.6 HVB-A y = 78.864ln(x) - 193.00 143 154 148 107 115 111 71 77 74 36 38 37 226 S 30 40.46 49.48 44.97 9.02 5.8 24.9 69.4 MVB y = 122.88ln(x) - 305.91 149 174 162 112 130 121 74 87 81 37 43 40 227 M 1 78.59 90.53 84.56 11.94 4.1 30.6 65.2 HVB-A y = 78.864ln(x) - 193.00 151 162 157 113 122 118 76 81 78 38 41 39 228 M 2 96.32 111.51 103.915 15.19 4.1 30.2 65.7 HVB-A y = 78.864ln(x) - 193.00 167 179 173 125 134 130 84 89 87 42 45 43 229 M 3 78.93 93.26 86.095 14.33 4.4 28.5 67.2 HVB-A y = 78.864ln(x) - 193.00 152 165 158 114 124 119 76 82 79 38 41 40 230 M 4 135.62 145 140.31 9.38 4.4 30.3 65.3 HVB-A y = 78.864ln(x) - 193.00 194 199 197 146 150 148 97 100 98 49 50 49 231 M 5 69.18 78.84 74.01 9.66 3.0 31.6 65.4 HVB-A y = 78.864ln(x) - 193.00 141 151 146 106 114 110 71 76 73 35 38 37 232 M 6 71.11 78.93 75.02 7.82 3.2 33.2 63.6 HVB-A y = 78.864ln(x) - 193.00 143 152 148 107 114 111 72 76 74 36 38 37 233 M 7 108.35 118.56 113.455 10.21 4.4 28.2 67.4 HVB-A y = 78.864ln(x) - 193.00 177 184 180 132 138 135 88 92 90 44 46 45 234 M 8 71.85 83.28 77.565 11.43 5.1 28.2 66.7 HVB-A y = 78.864ln(x) - 193.00 144 156 150 108 117 113 72 78 75 36 39 38 235 M 9 21.18 34.51 27.845 13.33 6.2 26.4 67.4 HVB-A y = 78.864ln(x) - 193.00 (1) 86 (1) (1) 65 (1) (1) 43 (1) (1) 22 (1) 236 M 10 0.1 11.07 5.585 11.07 6.5 26.3 67.2 HVB-A y = 78.864ln(x) - 193.00 (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) (1) 237 M 11 25.75 38.63 32.19 12.88 5.7 25.7 68.6 HVB-A y = 78.864ln(x) - 193.00 (1) 95 81 (1) 71 61 (1) 48 40 (1) 24 20 202 S e q u e n c e N e t t C o a l T h i c k n e s s ( m ) M o i s t u r e ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) M i n i m u m M a x i m u m A v e r a g e M i n i m u m M a x i m u m A v e r a g e M i n i m u m M a x i m u m A v e r a g e M i n i m u m M a x i m u m A v e r a g e Coal Interval Coal Quality Gas Content Calculated from Eddy, et al. (1982) Trend Line Equations (scf/T) Ash-Free Full Saturation (100%) 75% Saturation 50% Saturation 25% SaturationBorehole ID / Eddy, et al. (1982) Trend Field Name\ Sample Coal Line Equation From (m) To (m) Mid-Point Rank (m) Code L 256 (Type 238 Borehole - Main 15 190 102.5 9.17 14.8 29.7 55.5 HVB-B y = 52.803ln(x) - 141.04 (1) 136 103 (1) 102 78 (1) 68 52 (1) 34 26 & A Seams)* L 252 (Type 239 Borehole - Main 22.49766667 197.4976667 109.9976667 6.15 16.1 32.6 51.3 HVB-C y = 30.948ln(x) - 69.666 (1) 94 76 (1) 70 57 (1) 47 38 (1) 23 19 Seam)* L 198 (Type 240 Borehole -Lower & Middle 26.6 97.77 62.185 4.15 13.7 33.7 52.6 HVB-C y = 30.948ln(x) - 69.666 (1) 72 58 (1) 54 44 (1) 36 29 (1) 18 15 Seam)* 241 Shallow (Average)* 60 100 80 9 0.8 26.3 72.9 MVB y = 122.88ln(x) - 305.91 197 260 233 148 195 174 99 130 116 49 65 58 242 Deep(Average)* 200 700 450 9 0.8 26.3 72.9 MVB y = 122.88ln(x) - 305.91 345 499 445 259 374 334 173 250 222 86 125 111 243 Gokwe Average 200 300 9 5.3 29.3 65.3 HVB-A y = 78.864ln(x) - 193.00 225 257 242 169 193 182 112 128 121 56 64 61 244 N1/1 45.1 46.7 45.9 1 SBIT y = 6.2975ln(x) - 7.8369 16 16 16 12 12 12 8 8 8 4 4 4 245 N1/2 41 89 65 5.5 SBIT y = 6.2975ln(x) - 7.8369 16 20 18 12 15 14 8 10 9 4 5 5 246 N1/3 24 91 57.5 7.73 SBIT y = 6.2975ln(x) - 7.8369 (1) 21 18 (1) 15 13 (1) 10 9 (1) 5 4 247 N2/1 52.7 118.1 85.4 19.6 SBIT y = 6.2975ln(x) - 7.8369 17 22 20 13 17 15 9 11 10 4 6 5 248 N3/1 38.3 119 78.65 23.65 SBIT y = 6.2975ln(x) - 7.8369 15 22 20 11 17 15 8 11 10 4 6 5 249 N4/1 113.3 189 151.15 14.03 SBIT y = 6.2975ln(x) - 7.8369 22 25 24 16 19 18 11 13 12 5 6 6 250 N5/2 5 41.7 23.35 6.8 SBIT y = 6.2975ln(x) - 7.8369 (1) 16 (1) (1) 12 (1) (1) 8 (1) (1) 4 (1) 251 N5/1 10.4 41.2 25.8 4.1 SBIT y = 6.2975ln(x) - 7.8369 (1) 16 (1) (1) 12 (1) (1) 8 (1) (1) 4 (1) 252 N6/1 14.7 70.5 42.6 2.5 SBIT y = 6.2975ln(x) - 7.8369 (1) 19 16 (1) 14 12 (1) 9 8 (1) 5 4 253 N8/2 75.35 124.5 99.925 11.5 SBIT y = 6.2975ln(x) - 7.8369 19 23 21 15 17 16 10 11 11 5 6 5 254 N12/1 79.9 150.85 115.375 12.5 SBIT y = 6.2975ln(x) - 7.8369 20 24 22 15 18 17 10 12 11 5 6 6 255 N9/1 75.4 124.6 100 8.74 SBIT y = 6.2975ln(x) - 7.8369 19 23 21 15 17 16 10 11 11 5 6 5 256 N10/1 89.4 177.3 133.35 21.76 SBIT y = 6.2975ln(x) - 7.8369 20 25 23 15 19 17 10 12 11 5 6 6 257 N11/3 110.6 153.5 132.05 8.15 SBIT y = 6.2975ln(x) - 7.8369 22 24 23 16 18 17 11 12 11 5 6 6 258 N7/1 259 N7/2 260 N7/3 261 N8/1 262 N8/2 263 N12/1 264 N9/1 265 N10/1 266 N11/3 203 S e q u e n c e N e t t C o a l T h i c k n e s s ( m ) M o i s t u r e ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) M i n i m u m M a x i m u m A v e r a g e M i n i m u m M a x i m u m A v e r a g e M i n i m u m M a x i m u m A v e r a g e M i n i m u m M a x i m u m A v e r a g e Coal Interval Coal Quality Gas Content Calculated from Eddy, et al. (1982) Trend Line Equations (scf/T) Ash-Free Full Saturation (100%) 75% Saturation 50% Saturation 25% SaturationBorehole ID / Eddy, et al. (1982) Trend Field Name\ Sample Coal Line Equation From (m) To (m) Mid-Point Rank (m) Code 267 N11/2 268 N11/1 269 N12/1 270 N12/2 271 N12/3 272 Y1-01 499.74 566.3 533.02 10.652 SBIT y = 6.2975ln(x) - 7.8369 31 32 32 23 24 24 16 16 16 8 8 8 273 Y1-02 705.536 737.136 721.336 1.29 SBIT y = 6.2975ln(x) - 7.8369 33 34 34 25 25 25 17 17 17 8 8 8 274 Y1-03 705.73 792.74 749.235 16.75 SBIT y = 6.2975ln(x) - 7.8369 33 34 34 25 26 25 17 17 17 8 9 8 275 Y1-04 587.2 605.5 596.35 2.85 SBIT y = 6.2975ln(x) - 7.8369 32 33 32 24 24 24 16 16 16 8 8 8 276 PDM006C 277 PDM007A 278 PDM008 279 PDM009 280 PDM011 281 PDM014A 282 PDM015 283 Lubimbi 11.8 190 100.9 HVB-C y = 30.948ln(x) - 69.666 (1) 93 73 (1) 70 55 (1) 46 37 (1) 23 18 284 Busi 60 80 70 10 SBIT y = 6.2975ln(x) - 7.8369 18 20 19 13 15 14 9 10 9 4 5 5 Tjolotjo, 285 Sawmills, and 270 330 300 5 SBIT y = 6.2975ln(x) - 7.8369 27 29 28 21 22 21 14 14 14 7 7 7 Insuza 204 S e q u e n c e N e t t C o a l T h i c k n e s s ( m ) M o i s t u r e ( % ) V o l a t i l e M a t t e r ( % ) F i x e d C a r b o n ( % ) M i n i m u m M a x i m u m A v e r a g e M i n i m u m M a x i m u m A v e r a g e M i n i m u m M a x i m u m A v e r a g e M i n i m u m M a x i m u m A v e r a g e Appendix D List of isotherm samples collected and analysed by Kubu Energy (after Faiz, et al., 2013). Sample Analyses Sampling Intrusives Measured Gas Content Proximate Analysis Isotherm Analyses Air Dried Ash-Free (m) (m) (m) scf/T scf/T % % % % % % % % VR (mean) 1 135C9 405.7 406.3 406 CH-9-002 UMH 1.61 11.33 20.14 3.81 39.94 22.04 34.21 6.34 36.70 56.96 0.51 2 135C9 420.8 421.4 421.1 CH-9-008 Z3 1.61 74.60 184.70 1.52 58.09 6.03 34.37 3.63 14.38 81.99 3.67 3 135C9 444.21 444.81 444.51 CH-9-018 Z3 43.46 20.61 35.86 1.91 40.61 15.51 41.97 3.22 26.12 70.67 1.30 4 135C9 504.6 505.2 504.9 CH-9-028 Z2 43.46 26.86 120.29 3.40 74.27 5.95 16.38 13.22 23.11 63.66 4.71 5 135C9 520.86 521.46 521.16 CH-9-031 Z1 43.46 37.31 52.34 2.07 26.64 17.82 53.46 2.82 24.29 72.88 1.88 6 134C8 370.48 370.86 370.67 CH-8-002 UMH 13.09 19.37 3.36 29.07 33.58 33.99 4.74 47.34 47.92 0.40 7 134C8 385.62 386.22 385.92 CH-8-005 Z3 73.43 9.03 12.19 3.15 22.79 27.91 46.15 4.08 36.15 59.77 0.62 8 134C8 387.88 388.48 388.18 CH-8-012 Z3 73.43 40.07 79.16 2.66 46.71 16.99 33.64 5.00 31.88 63.12 0.90 9 134C7 403.83 404.43 404.13 CH-7-002 UMH 11.30 17.69 6.36 29.78 32.85 31.01 9.06 46.78 44.16 0.50 10 134C7 432.36 432.96 432.66 CH-7-011 Z3 17.77 21.85 4.78 13.91 33.51 47.81 5.55 38.92 55.53 0.54 11 134C7 439.95 440.55 440.25 CH-7-016 Z3 17.12 23.18 3.52 22.65 28.88 44.95 4.55 37.34 58.11 0.54 12 134C7 462.86 463.14 463 CH-7-021 Z2 26.78 32.12 3.72 12.91 32.05 51.33 4.27 36.80 58.94 0.55 13 134C7 485.62 486.22 485.92 CH-7-025 Z1 21.25 100.26 130.89 1.30 22.10 9.42 67.18 1.67 12.09 86.24 3.88 14 134C6 319.59 320.19 319.89 CH-6-002 Z3 21.78 42.05 5.99 42.21 23.38 28.41 10.37 40.46 49.17 0.47 15 134C6 328.84 329.4 329.12 CH-6-008 Z3 37.11 47.18 5.27 16.07 34.62 44.04 6.28 41.25 52.47 0.51 16 134C6 340.05 340.64 340.345 CH-6-013 Z2 39.94 49.05 4.98 13.60 32.00 49.41 5.77 37.04 57.19 0.60 17 134C6 355.5 355.99 355.745 CH-6-016 Z1 12.43 36.05 2.42 63.10 13.18 21.30 6.57 35.72 57.71 0.65 18 135C5 247.77 248.5 248.135 CH-05-D1 UMH 13.83 26.84 36.47 1.85 24.56 22.65 50.94 2.45 30.03 67.52 1.00 19 135C5 283 283.25 283.125 CH-05-D2 Z3 1.21 22.39 45.63 2.43 48.50 6.57 42.50 4.71 12.75 82.54 5.33 20 135C5 325.77 328.46 327.115 CH-05-D5 Z3 2.91 13.11 19.74 2.21 31.35 23.61 42.83 3.22 34.39 62.39 1.40 21 135C5 335.26 336.29 335.775 CH-05-D9 Z2 29.47 23.98 29.47 1.37 17.26 22.11 59.25 1.66 26.73 71.61 1.22 22 135C5 344.1 345.23 344.665 CH-05-D11 Z1 29.47 42.64 104.80 2.27 57.05 8.38 32.30 5.28 19.52 75.20 5.44 23 135C4 380.82 381.53 381.175 CH-04-D1 UMH 15.06 26.60 1.13 42.25 14.25 42.37 1.95 24.68 73.37 1.91 24 135C4 437.06 437.41 437.235 CH-04-D3 Z3 22.37 141.78 2.27 81.96 4.21 11.57 12.56 23.31 64.12 5.53 25 135C4 459.9 460.02 459.96 CH-04-D10 Z2 56.73 67.23 2.31 13.30 28.53 55.86 2.66 32.91 64.43 0.84 26 135C4 478.79 479.34 479.065 CH-04-D15 Z1 5.14 23.42 29.15 2.50 17.16 27.13 53.20 3.02 32.76 64.23 0.87 27 135C4 490.4 490.64 490.52 CH-04-D19 Z1 5.14 82.23 96.53 1.06 13.75 11.27 73.92 1.23 13.07 85.70 1.59 28 136C3 364.7 365 364.85 CH-03-005 Z3 37.55 50.12 2.10 22.98 29.07 45.84 2.73 37.75 59.52 0.83 29 136C3 374.94 375.54 375.24 CH-03-012 Z3 13.04 25.51 3.51 45.38 21.51 29.60 6.43 39.38 54.19 0.52 205 S a m p l e S e q u e n c e B o r e h o l e D e p t h F r o m D e p t h T o S a m p l e M i d - P o i n t D e p t h S a m p l e N u m b e r Z o n e G a s D e s o r p t i o n M e t h a n e N i t r o g e n C a r b o n D i o x i d e P r o x i m a t e A n a l y s i s V i t r i n i t e R e f l e c t a n c e P r o x i m i t y t o I n t r u s i v e < 3 0 m V e r t i c a l T h i c k e s t I n t r u s i v e T h i c k n e s s ( m ) R a w D r y , A s h - F r e e M o i s t u r e A s h V o l a t i l e M a t t e r F i x e d C a r b o n M o i s t u r e V o l a t i l e M a t t e r F i x e d C a r b o n V i t r i n i t e R e f l e c t a n c e S e l e c t e d f o r C o m p a r i s o n t o E d d y e t a l . ( 1 9 8 2 ) M e a s u r e d D a t a Sample Analyses Sampling Intrusives Measured Gas Content Proximate Analysis Isotherm Analyses Air Dried Ash-Free (m) (m) (m) scf/T scf/T % % % % % % % % VR (mean) 30 136C3 410.45 410.68 410.565 CH-03-013 Z2 29.84 28.06 33.45 4.32 11.79 31.45 52.44 4.89 35.65 59.45 0.64 31 136C3 417.95 418.55 418.25 CH-03-016 Z2 29.84 35.31 46.93 3.14 21.62 21.12 54.12 4.00 26.95 69.05 0.92 32 136C3 420.95 421.55 421.25 CH-03-018 Z1 29.84 38.70 54.22 2.05 26.58 17.49 53.88 2.79 23.83 73.39 1.39 33 136C2 257.64 258.25 257.945 CH-02-003 Z3 5.80 8.49 4.88 26.79 33.52 34.82 6.66 45.78 47.56 0.46 34 136C2 272.49 273.09 272.79 CH-02-007 Z3 50.12 22.97 32.60 2.69 26.84 27.69 42.78 3.67 37.85 58.48 0.77 35 136C2 276.51 276.74 276.625 CH-02-009 Z3 50.12 52.83 68.52 1.45 21.45 16.30 60.81 1.85 20.75 77.41 1.52 36 136C2 357.97 358.27 358.12 CH-02-011 Z2 50.12 31.01 47.87 0.76 34.45 18.77 46.02 1.16 28.63 70.20 1.57 37 136C1 245.82 246.29 246.055 CH-01 D002 UMH 18.45 25.55 5.65 22.11 28.74 43.49 7.25 36.90 55.84 0.44 38 136C1 268.38 268.98 268.68 CH-01 D004 Z3 33.23 44.71 5.45 20.23 31.50 42.82 6.84 39.49 53.68 0.47 39 136C1 275.24 275.44 275.34 CH-01 D005 Z3 33.13 45.05 5.43 21.04 30.70 42.84 6.87 38.87 54.25 0.49 40 136C1 277.3 277.9 277.6 CH-01 D006 Z3 33.32 51.03 4.71 29.99 25.84 39.46 6.73 36.91 56.36 0.47 41 136C1 279.96 280.17 280.065 CH-01 D008 Z3 32.33 39.16 5.08 12.37 32.94 49.62 5.79 37.59 56.62 0.50 206 S a m p l e S e q u e n c e B o r e h o l e D e p t h F r o m D e p t h T o S a m p l e M i d - P o i n t D e p t h S a m p l e N u m b e r Z o n e G a s D e s o r p t i o n M e t h a n e N i t r o g e n C a r b o n D i o x i d e P r o x i m a t e A n a l y s i s V i t r i n i t e R e f l e c t a n c e P r o x i m i t y t o I n t r u s i v e < 3 0 m V e r t i c a l T h i c k e s t I n t r u s i v e T h i c k n e s s ( m ) R a w D r y , A s h - F r e e M o i s t u r e A s h V o l a t i l e M a t t e r F i x e d C a r b o n M o i s t u r e V o l a t i l e M a t t e r F i x e d C a r b o n V i t r i n i t e R e f l e c t a n c e S e l e c t e d f o r C o m p a r i s o n t o E d d y e t a l . ( 1 9 8 2 ) M e a s u r e d D a t a Appendix E Gas content values from the Shangani Energy exploration data digitised from the Barker (2006) graph. Sequence Area Borehole Name Depth Digitised Gas Content from Baker Digitised from (2006) Graph Baker (2006) Graph (m) (scf/T) 1 Hwange C6-Hwange 682 328 2 Hwange C6-Hwange 700 337 3 Hwange C6-Hwange 732 409 4 Hwange C6-Hwange 738 280 5 Hwange C6-Hwange 775 284 6 Hwange C6-Hwange 738 261 7 Hwange C6-Hwange 699 250 8 Hwange C6-Hwange 698 243 9 Hwange C6-Hwange 679 244 10 Hwange C6-Hwange 688 252 11 Hwange C6-Hwange 734 246 12 Hwange C6-Hwange 753 243 13 Hwange C6-Hwange 753 227 14 Hwange C6-Hwange 769 235 15 Hwange C6-Hwange 740 221 16 Hwange C6-Hwange 694 211 17 Hwange C6-Hwange 676 195 18 Hwange C6-Hwange 671 188 19 Hwange C6-Hwange 683 182 20 Hwange C6-Hwange 676 167 21 Hwange C6-Hwange 687 141 22 Hwange C6-Hwange 674 106 23 Hwange C6-Hwange 739 113 24 Hwange C6-Hwange 756 112 25 Hwange C6-Hwange 762 101 26 Hwange C6-Hwange 771 59 27 Hwange C6-Hwange 760 56 28 Hwange C6-Hwange 765 51 29 Hwange C6-Hwange 745 44 30 Hwange C6-Hwange 741 31 31 Hwange C6-Hwange 766 30 32 Hwange C6-Hwange 677 56 33 Sengwa RTZ-Sengwa 261 9 34 Sengwa RTZ-Sengwa 270 15 35 Sengwa RTZ-Sengwa 270 15 36 Sengwa RTZ-Sengwa 268 24 37 Sengwa RTZ-Sengwa 268 24 38 Sengwa RTZ-Sengwa 278 31 207 Sequence Area Borehole Name Depth Digitised Gas Content from Baker Digitised from (2006) Graph Baker (2006) Graph (m) (scf/T) 39 Sengwa RTZ-Sengwa 284 30 40 Sengwa RTZ-Sengwa 284 30 41 Sengwa RTZ-Sengwa 281 21 42 Sengwa RTZ-Sengwa 288 19 43 Sengwa RTZ-Sengwa 293 33 44 Sengwa RTZ-Sengwa 303 32 45 Sengwa RTZ-Sengwa 310 29 46 Sengwa RTZ-Sengwa 310 29 47 Sengwa RTZ-Sengwa 311 20 48 Sengwa RTZ-Sengwa 316 28 49 Sengwa RTZ-Sengwa 326 27 50 Sengwa RTZ-Sengwa 326 27 51 Sengwa RTZ-Sengwa 336 29 52 Sengwa RTZ-Sengwa 336 29 53 Sengwa RTZ-Sengwa 336 29 54 Sengwa RTZ-Sengwa 338 39 55 Sengwa RTZ-Sengwa 332 42 56 Sengwa RTZ-Sengwa 332 42 57 Sengwa RTZ-Sengwa 332 42 58 Sengwa RTZ-Sengwa 332 42 59 Sengwa RTZ-Sengwa 338 39 60 Sengwa RTZ-Sengwa 342 32 61 Sengwa RTZ-Sengwa 336 29 62 Sengwa RTZ-Sengwa 332 20 63 Sengwa RTZ-Sengwa 332 20 64 Gwaai C2-Gwaai 327 4 65 Gwaai C2-Gwaai 284 3 66 Gwaai C2-Gwaai 306 3 67 Gwaai C2-Gwaai 303 12 68 Gwaai C2-Gwaai 295 26 69 Gwaai C2-Gwaai 304 37 70 Gwaai C2-Gwaai 290 37 71 Gwaai C2-Gwaai 294 53 72 Gwaai C2-Gwaai 294 53 73 Gwaai C2-Gwaai 302 77 74 Gwaai C2-Gwaai 309 79 75 Gwaai C2-Gwaai 309 87 76 Gwaai C2-Gwaai 309 100 77 Gwaai C2-Gwaai 298 116 78 Gwaai C2-Gwaai 219 46 208 Sequence Area Borehole Name Depth Digitised Gas Content from Baker Digitised from (2006) Graph Baker (2006) Graph (m) (scf/T) 79 Gwaai C2-Gwaai 242 53 80 Gwaai C2-Gwaai 264 54 81 Gwaai C2-Gwaai 249 39 82 Gwaai C2-Gwaai 222 26 83 Gwaai C2-Gwaai 208 21 84 Gwaai C2-Gwaai 201 19 85 Gwaai C2-Gwaai 220 14 86 Gwaai C2-Gwaai 209 7 87 Gwaai C2-Gwaai 219 5 88 Gwaai C2-Gwaai 172 6 89 Gwaai C2-Gwaai 248 1 90 Gwaai C2-Gwaai 275 5 91 Gwaai C3-Gwaai 348 169 92 Gwaai C3-Gwaai 358 216 93 Gwaai C3-Gwaai 402 199 94 Gwaai C3-Gwaai 411 188 95 Gwaai C3-Gwaai 414 177 96 Gwaai C3-Gwaai 414 168 97 Gwaai C3-Gwaai 414 168 98 Gwaai C3-Gwaai 441 166 99 Gwaai C3-Gwaai 420 151 100 Gwaai C3-Gwaai 438 151 101 Gwaai C3-Gwaai 438 151 102 Gwaai C3-Gwaai 442 209 103 Gwaai C3-Gwaai 443 221 104 Gwaai C3-Gwaai 410 109 105 Gwaai C3-Gwaai 407 122 106 Gwaai C3-Gwaai 425 132 107 Gwaai C3-Gwaai 418 131 108 Gwaai C3-Gwaai 442 145 109 Gwaai C3-Gwaai 399 143 110 Gwaai C3-Gwaai 409 152 111 Gwaai C3-Gwaai 427 110 112 Gwaai C3-Gwaai 424 101 113 Gwaai C3-Gwaai 424 101 114 Gwaai C3-Gwaai 436 97 115 Gwaai C3-Gwaai 448 107 116 Gwaai C3-Gwaai 448 91 117 Gwaai C3-Gwaai 421 90 118 Gwaai C3-Gwaai 437 72 209 Sequence Area Borehole Name Depth Digitised Gas Content from Baker Digitised from (2006) Graph Baker (2006) Graph (m) (scf/T) 119 Gwaai C3-Gwaai 434 59 120 Gwaai C3-Gwaai 446 50 121 Gwaai C3-Gwaai 449 58 122 Gwaai C3-Gwaai 437 49 123 Gwaai C3-Gwaai 353 47 124 Gwaai C3-Gwaai 352 40 125 Gwaai C3-Gwaai 374 51 126 Gwaai C3-Gwaai 379 70 127 Gwaai C3-Gwaai 361 65 128 Gwaai C3-Gwaai 351 67 129 Gwaai C3-Gwaai 352 77 130 Gwaai C3-Gwaai 345 76 131 Gwaai C3-Gwaai 339 71 132 Gwaai C3-Gwaai 347 98 133 Gwaai C3-Gwaai 335 108 134 Gwaai C3-Gwaai 365 119 135 Gwaai C3-Gwaai 359 153 136 Gwaai C3-Gwaai 342 157 137 Gwaai C3-Gwaai 413 24 138 Gwaai C3-Gwaai 413 16 139 Gwaai C3-Gwaai 418 12 140 Gwaai C3-Gwaai 429 4 141 Gwaai C3-Gwaai 414 2 142 Gwaai C3-Gwaai 443 18 143 Gwaai C3-Gwaai 414 2 144 Gwaai C3-Gwaai 405 13 145 Gwaai C3-Gwaai 360 9 146 Gwaai C3-Gwaai 350 6 147 Gwaai C3-Gwaai 243 29 148 Gwaai C3-Gwaai 251 20 149 Gwaai C3-Gwaai 255 62 150 Gwaai C3-Gwaai 255 62 151 Gwaai C3-Gwaai 230 2 152 Gwaai C4-Gwaai 424 277 153 Gwaai C4-Gwaai 422 262 154 Gwaai C4-Gwaai 410 262 155 Gwaai C4-Gwaai 398 262 156 Gwaai C4-Gwaai 392 255 157 Gwaai C4-Gwaai 408 235 158 Gwaai C4-Gwaai 407 228 210 Sequence Area Borehole Name Depth Digitised Gas Content from Baker Digitised from (2006) Graph Baker (2006) Graph (m) (scf/T) 159 Gwaai C4-Gwaai 424 247 160 Gwaai C4-Gwaai 431 210 161 Gwaai C4-Gwaai 422 214 162 Gwaai C4-Gwaai 428 195 163 Gwaai C4-Gwaai 428 179 164 Gwaai C4-Gwaai 427 167 165 Gwaai C4-Gwaai 431 154 166 Gwaai C4-Gwaai 431 154 167 Gwaai C4-Gwaai 382 160 168 Gwaai C4-Gwaai 393 159 169 Gwaai C4-Gwaai 395 169 170 Gwaai C4-Gwaai 395 179 171 Gwaai C4-Gwaai 395 179 172 Gwaai C4-Gwaai 396 188 173 Gwaai C4-Gwaai 386 198 174 Gwaai C4-Gwaai 408 146 175 Gwaai C4-Gwaai 410 140 176 Gwaai C4-Gwaai 418 131 177 Gwaai C4-Gwaai 418 131 178 Gwaai C4-Gwaai 417 121 179 Gwaai C4-Gwaai 417 113 180 Gwaai C4-Gwaai 437 106 181 Gwaai C4-Gwaai 434 96 182 Gwaai C4-Gwaai 432 44 183 Gwaai C4-Gwaai 432 37 184 Gwaai C4-Gwaai 384 4 185 Gwaai C4-Gwaai 374 9 186 Gwaai C4-Gwaai 380 25 187 Gwaai C4-Gwaai 392 28 188 Gwaai C4-Gwaai 384 36 189 Gwaai C4-Gwaai 383 43 190 Gwaai C4-Gwaai 341 62 191 Gwaai C4-Gwaai 334 53 192 Gwaai C4-Gwaai 209 67 193 Gwaai C4-Gwaai 218 66 194 Gwaai C4-Gwaai 236 63 195 Gwaai C4-Gwaai 236 63 196 Gwaai C4-Gwaai 246 69 197 Gwaai C4-Gwaai 258 74 198 Gwaai C4-Gwaai 258 74 211 Sequence Area Borehole Name Depth Digitised Gas Content from Baker Digitised from (2006) Graph Baker (2006) Graph (m) (scf/T) 199 Gwaai C4-Gwaai 263 61 200 Gwaai C4-Gwaai 254 49 201 Gwaai C4-Gwaai 254 40 202 Gwaai C4-Gwaai 254 31 203 Gwaai C4-Gwaai 258 24 204 Gwaai C4-Gwaai 266 27 205 Gwaai C4-Gwaai 287 14 206 Gwaai C4-Gwaai 197 7 207 Gwaai C4-Gwaai 266 93 208 Gwaai C4-Gwaai 286 105 209 Gwaai C4-Gwaai 246 104 210 Gwaai C4-Gwaai 255 106 211 Gwaai C4-Gwaai 256 120 212 Gwaai C4-Gwaai 256 129 213 Gwaai C4-Gwaai 221 130 214 Gwaai C4-Gwaai 245 159 215 Gwaai C4-Gwaai 256 224 216 Gwaai C4-Gwaai 334 85 217 Gwaai C4-Gwaai 333 99 218 Gwaai C4-Gwaai 346 136 219 Gwaai C4-Gwaai 348 122 220 Gwaai C4-Gwaai 361 131 221 Gwaai C4-Gwaai 352 113 222 Gwaai C4-Gwaai 362 106 223 Gwaai C4-Gwaai 362 97 224 Gwaai C4-Gwaai 373 105 225 Gwaai C4-Gwaai 379 112 226 Gwaai C4-Gwaai 390 108 227 Gwaai C4-Gwaai 404 97 228 Gwaai C4-Gwaai 399 105 229 Gwaai C4-Gwaai 348 23 230 Gwaai C4-Gwaai 345 16 231 Gwaai C4-Gwaai 345 16 232 Gwaai C4-Gwaai 340 9 233 Lupane C5-Lupane 505 175 234 Lupane C5-Lupane 525 159 235 Lupane C5-Lupane 519 155 236 Lupane C5-Lupane 558 141 237 Lupane C5-Lupane 545 129 238 Lupane C5-Lupane 553 127 212 Sequence Area Borehole Name Depth Digitised Gas Content from Baker Digitised from (2006) Graph Baker (2006) Graph (m) (scf/T) 239 Lupane C5-Lupane 563 110 240 Lupane C5-Lupane 563 110 241 Lupane C5-Lupane 555 98 242 Lupane C5-Lupane 567 91 243 Lupane C5-Lupane 579 66 244 Lupane C5-Lupane 558 55 245 Lupane C5-Lupane 558 47 246 Lupane C5-Lupane 544 37 247 Lupane C5-Lupane 508 26 248 Lupane C5-Lupane 514 47 249 Lupane C5-Lupane 535 50 250 Lupane C5-Lupane 514 69 251 Lupane C5-Lupane 502 60 252 Lupane C5-Lupane 492 55 253 Lupane C5-Lupane 485 71 254 Lupane C5-Lupane 499 73 255 Lupane C5-Lupane 506 82 256 Lupane C5-Lupane 496 94 257 Lupane C5-Lupane 479 91 258 Lupane C5-Lupane 460 84 259 Lupane C5-Lupane 485 71 260 Lupane C5-Lupane 494 79 261 Lupane C5-Lupane 543 97 262 Lupane C5-Lupane 528 94 263 Lupane C5-Lupane 529 107 264 Lupane C5-Lupane 524 112 265 Lupane C5-Lupane 518 124 266 Lupane C5-Lupane 510 118 267 Lupane C5-Lupane 469 125 268 Lupane C5-Lupane 453 124 269 Lupane C5-Lupane 469 125 270 Lupane C5-Lupane 559 87 271 Lupane C5-Lupane 552 77 272 Lupane C5-Lupane 552 69 273 Lupane C5-Lupane 525 69 274 Lupane C5-Lupane 420 51 275 Lupane C5-Lupane 408 82 276 Lupane C5-Lupane 445 69 277 Lupane C5-Lupane 439 78 278 Lupane C5-Lupane 401 41 213 Sequence Area Borehole Name Depth Digitised Gas Content from Baker Digitised from (2006) Graph Baker (2006) Graph (m) (scf/T) 279 Lupane C5-Lupane 413 50 280 Entuba ZG-Entuba 363 3 281 Entuba ZG-Entuba 363 3 282 Entuba ZG-Entuba 373 3 283 Entuba ZG-Entuba 496 5 284 Entuba ZG-Entuba 501 10 285 Entuba ZG-Entuba 485 6 286 Entuba ZG-Entuba 496 5 287 Entuba ZG-Entuba 467 10 288 Entuba ZG-Entuba 467 21 289 Entuba ZG-Entuba 483 20 290 Entuba ZG-Entuba 478 31 291 Entuba ZG-Entuba 474 42 292 Entuba ZG-Entuba 473 36 293 Entuba ZG-Entuba 401 21 294 Entuba ZG-Entuba 401 21 295 Entuba ZG-Entuba 392 88 296 Entuba ZG-Entuba 388 104 297 Entuba ZG-Entuba 392 88 298 Entuba ZG-Entuba 388 79 299 Entuba ZG-Entuba 388 79 300 Entuba ZG-Entuba 388 79 301 Entuba ZG-Entuba 390 66 302 Entuba ZG-Entuba 397 67 303 Entuba ZG-Entuba 396 60 304 Entuba ZG-Entuba 390 58 305 Entuba ZG-Entuba 381 61 306 Entuba ZG-Entuba 392 42 307 Entuba ZG-Entuba 378 29 308 Entuba ZG-Entuba 368 27 309 Entuba ZG-Entuba 360 26 310 Entuba ZG-Entuba 365 37 311 Entuba ZG-Entuba 365 54 312 Entuba ZG-Entuba 393 17 313 Entuba ZG-Entuba 394 25 214