u.o.v . IBLlOT University Free State 111/1111111111111111111111111111111111111111111 1111111111 11111111111111111111111 34300000363006 Universiteit Vrystaat HIERDIE EKSEMPlAAR MAG ONDER GEEN OMSTANDIGHEDE UIT DIE ~fH_I.IOTE-Ef<-VER-\.VY-DER-WO-RD-NIE.,.. THE ASSESSMENT OF POTENTIAL RADIATION HAZARDS FROM GOLD MINES IN THE FREE STATE GOLDFIELDS TO MEMBERS OF THE PUBLIC by Jozua Francois Ellis A dissertation submitted in order to meet the requirements for the degree Master in Medical Sciences (M.Med.Sc.) in the Faculty of Health Sciences (Department of Medical Physics) at the University of the Orange Free State. November 1998 Supervisor: Dr J C Botha Joint Supervisor: Prof A van Aswegen DECLARA TION I declare that the dissertation hereby submitted by me, Jozua Francois Ellis, for the degree Master in Medical Sciences (M.Med.Sc.) at the University of the Orange Free State, is my own independent work and that I have not previously submitted the same work for a degree at/in another university/faculty. I furthermore cede copyright of the dissertation to the University of the Orange Free State. Signed: Place: ------------------ Date: JF Ellis I dedicate this study to my father who has been my inspiration in life. PREFACE This study is the result of teamwork and commitment by a whole group of people. I sincerely thank the following individuals and companies, without whom this study would not have been possible: • My supervisors, especially Dr Johan Botha for his guidance, support and patience. • Anglogold for its financial and technical support. • Charl Human for his mind-boggling computer skills. • The management and staff of the Anglogold Free State Operations, specifically Jimmy Soden, Takkie du Toit and Klaas Rooi who did a lot of legwork. • My family and friends for their support. • My wife, Benita, who had to bear the brunt of the late nights and short tempers. I finally thank my Creator without whom nothing is possible. THE ASSESSMENT OF POTENTIAL RADIATION HAZARDS FROM GOLD MINES IN THE FREE STATE GOLDFIELDS TO MEMBERS OF THE PUBLIC CONTENTS CHAPTER 1 INTRODUCTION CHAPTER 2 PROCESS DESCRIPTION AND SITE CHARACTERISATION CHAPTER 3 POTENTIAL EXPOSURE PATHWAYS CHAPTER4 SOURCE TERM DETERMINATION CHAPTER 5 MODELLING CHAPTER 6 ENVIRONMENTAL MEASUREMENTS AND ANALYSES CHAPTER 7 CONCLUSIONS APPENDIX 1 APPENDIX 2 BIBLIOGRAPHY SUMMARY CHAPTER 1 INTRODUCTION 1-1 1 INTRODUCTION The gold mines in the Free State extract and process ore that contains naturally occurring radioactive uranium and its associated decay products. In terms of the nuclear licences 1 issued to the gold mines, it is required by the Council for Nuclear Safetl (local regulator) to assess potential radiation exposures to members of the public. In addition to this legal requirement, the mines have a moral obligation towards the public to assess the impact of radioactive effluents from their sites. The International Commission on Radiological Protection (ICRP) Publication 603 states that no practice involving exposures to radiation should be adopted unless it produces sufficient benefit to the exposed individuals or to society to offset the radiation detriment it causes. Exposures should be kept as low as reasonably achievable, economic and social factors being taken into account. Any proposed intervention into existing and/or planned activities should do more good than harm, i.e. the reduction in detriment resulting from the reduction in dose should be sufficient to justify the harm and the costs, including social costs, of the intervention. This assessment endeavoured to cost effectively quantify the potential exposure of members of the public to radiation hazards originating from the major mining and minerals processing facilities in the Free State Goldtields". Due to the vast area of the mining operations in the Free State, an area of some 80 square kilometres, it is a major challenge to conduct a cost-effective, yet representative public hazard assessment within the financial constraints of the 1 Nuclear Licence NL-57 2 Nuclear Energy Act, 1993 (Act No 131 of 1993) 3 Annals of the ICRP, Publication 60 Recommendations of the International Commission on Radiological Protection, International Commission on Radiological Protection. 4 Environmental Management Programme Report (1997) Version 4, Free State Consolidated Gold Mines (Operations) Limited 1-2 gold mining industry. In addition, the significance of the potential radiation exposure is expected to be in the order of natural background levels and an elaborate and expensive assessment is not justified. The general strateqy'' for assessing potential public exposures was to: II conduct limited monitoring of potential sources of radioactivity (source terms), II model the potential exposures to the public from the different source terms, II conduct environmental monitoring to validate modelling results and background levels, and II recommend corrective actions and future monitoring programmes, if required. 5 Council for Nuclear Safety, Licensing guide LG-1032 Revision 0 (April 1997), Guideline on the assessment of radiation hazards to members of the public from mining and minerals processing facilities. 1-3 CHAPTER 2 PROCESS DESCRIPTION AND SITE CHARACTERISATION 2.1 PROCESS DESCRIPTION 2-2 2.2 REGIONAL SETTING 2-6 2.3 GEOLOGY AND TOPOGRAPHY 2-7 2.4 CLIMATE 2-7 2.5 SOCIO-ECONOMIC STRUCTURES 2-9 2-1 2.1 PROCESS DESCRIPTION The mines in the Free State Goldfields are situated in the south-western part of the Witwatersrand Basin 1 and extracts most of their gold bearing ore from the Basal Reef at a depth of between 1000 to 3000 metres below surface. Gold is the primary product with ore reserves of some 25 million tons at an estimated gold value of up to 14.2 grams per ton (git). By-products such as uranium and sulphuric acid was produced up to the early 1990's. A typical gold mining operation consists of the following: Shafts and underground developments from which gold bearing ore is brought to surface for processing. The underground areas consist of literally thousands of kilometres of passages that provide access to working areas and in which ore and waste rock are returned to main shafts for extraction to the surface. Major ventilation systems provide fresh air to working areas and extract old air consisting of fumes and gasses, including radioactive radon gas, to the upeast discharge shafts on surface. Metallurgical plants process and extract gold from the ore from underground. A typical gold recovery circuit consists of the following operations'': • Crushing and screening section - ore received from underground mining activities is fed through the crushing and screening section where the ore is crushed under dry conditions • Milling section - during a wet milling process the particle size is reduced to an optimum level for treatment. • Thickening - prior to cyanide leaching the percentage of water in the pulp is reduced in thickener or settler units. 1 Environmental Management Programme Report (1997) Version 4, Free State Consolidated Gold Mines (Operations) Limited 2 Operating procedures and process flow diagrams, (Personal communications from Plant Management at Anglogold) 2-2 • Cyanidation - lime is added for pH control after which cyanide is added to the pulp for leaching of the gold bearing solution. • Filtration or Carbon In Pulp (CIP) gold extraction - during filtration the gold bearing solution is separated from the solids and the residue is then pumped to the slimes dams for final disposal. In recent times more efficient carbon adsorption and elution have replaced the use of filtration systems. • Gold is recovered from solution via zinc precipitation and filtration. Again the residue solutions are diluted to the slimes dams. • Gold melting - precipitated gold is melted into bars of 95% pure gold in the smelt houses situated on site. The final product is then sent to a refinery for final processing and refinement to 99% gold. Waste rock dumps - waste rock usually consists of rock extracted during shaft sinking and underground developments i.e. the balance of the rock that does not contain gold bearing reef. The waste rock may still contain minimal gold concentrations and may be re-processed if financially feasible. Tailings or slimes dams - the waste product from the metallurgical plants are stored in massive storage dams. These dams can be up to a few kilometres in circumference and up to 50 metres height. There are more than 30 tailings dams covered in the scope of this assessment, with the total surface area covered by tailings amounting to more than 3000 ha. Most tailings dams are equipped with under-drains to prevent seepage. Each slimes dam has a diversionary system of drains around the perimeter of the dam to store and control storm water and sediment washed off the walls of the dam. Both seepage and run-off is drained back into the return water or process dams for re-use. Process water dams - provide storage and supply of large volumes of water used in the metallurgical plants and the cooling and mining activities on the shafts. ~ I 2-3 The following figures provide a summary of a typical gold mining operation: Process Waste Rock Dumps Tailings dams ____ -->1 " I _' I .J '~ I 1 I ~.__.l,..'~ - ;' t ........~...l.. . LIk .' • I . ' 1 1 ~ .. 1-- I' .- . . , . Jl I • I ~ I Rock from ... _:l ... I r underground _ I 1 -, "t to shafts ,J, • ,I • ',' l .: 'L' .' Figure 2-1: A typical gold mining process 2-4 Tailings dam Figure 2-2: The above photograph indicates the magnitude of a typical tailings darn" in relation to the environment. The tailings dam in the forefront is a dry, dormant dam that has been rehabilitated and grassed on the side slopes. The dam at the back is wet and still operational. 3 Photograph compliments of Anglogold, Free State Business Services 2-5 2.2 REGIONAL SETTING The total mining area covers approximately 30 000 ha and includes the majority of mines and/or groups of mines in the Free State Goldfields. The mines are located in and around the towns of Odendaalsrus, Welkom and Virginia in the Free State". The land surrounding the mines is mainly used for agricultural purposes with both grazing and crop farming being practised. The mines are situated in the Sand- Vet River water catchment area, which ultimately drains into the Bloemhof dam and greater Vaal River system. Goudveld Water supplies potable water to the area from mainly the Vaal River system, with a small contribution from a canal on the Sand River systems. The majority of the surface mining land is used for cultivation of maize and wheat with small amounts of sunflower making up the balance of crops. The veld type in the area is typical of that on the Highveld. 4 Environmental Management Programme Report (1997) Version 4, Free State Consolidated Gold Mines (Operations) Limited 5 Water Management Plan Volume 8 (1997), Free State Goldfields and Lower Vet River catchment, Department of Water Affairs and Forestry 2-3, 8-14 2-6 2.3 GEOLOGY AND TOPOGRAPHY The Free State Goldfields are situated in the Highveld region of Southern Africa" with a surface elevation ranging between 1300m to 1400m above sea level. The geology comprises mainly of sandstone, siltstone and mudstone of the lower Beaufort and Upper Ecca Groups. The Ecca sediments in the north-west are generally finer and less permeable than the courser Beaufort sediments to the south-east. The low surface relief gives rise to the formation of many natural pans that collect water during the wet summer months and often dry out during the winter. The topographical characteristic of the area is that of a flat plain with no distinguishing features such as hills or mountains in the area. The Sand River traverses the area from east to west. The surface area has been divided into approximately ten surface water catchment areas with the Sand River and Mahemspruit being the major focus areas in terms of potential water pollution in general. 2.4 CLIMATE The regional climate is typical of the Highveld with moderately wet, warm summers and cold dry winters. The area falls within the summer rainfall region and receives an annual precipitation in the order of 530 mm per annum. The annual average temperature is 17 °C with an average maximum of 24 °C and an average minimum of 10 °C. The mean wind direction is from the north north-east with gusts of up to 100 km/h during rainstorms. 6 Environmental Management Programme Report (1997) Version 4, Free State Consolidated Gold Mines (Operations) Limited 2-7 The wind rose in Figure 2-3 summarises the predominant wind speeds and directions for the period considered in the assessment. This is based on 5 minute weather data? which was also used in the radon gas dispersion modelling discussed in Chapter 5. WINDROSE8 (Period 1 January 1997 to 31 December 1997) Figure 2-3: Windrose for Welkom (1997) 7 South African Weather Bureau, Five minute weather data for 1OO? (supplied electronically) 8Windrose Plot, IAEA Software Programme, SCRAM Bulletin Board 2-8 2.5 SOCIO-ECONOMIC STRUCTURES Gold mines in the area have been in operation for more than forty years and the regional socio-economic structure has developed from a rural, sparsely populated farming community into that of an urban, mining based semi-industrial city. The support industries for the mining activities constitute the majority of economic activity in the area. The major economic activities" can be summarised as follows (Table2-1): Table 2-1: Socio-economic structure of the Free State Goldfields Agriculture 4.1% Mining 67.1 % Manufacturing 3.7 % Construction 5.8 % Commercial 7.3 % Transport 1.0 % Services 11.1 % From the above table it is clear that the gold mining activities has a major socio- economic impact on the area, especially in terms of providing income and financial security to the majority of the population in the Free State Goldfields. It is against these and other benefits that the potential radiological impact, or any other environmental impact, must be rneasured'". 9 Goldfields Population Statistics for 1995. 10 Annals of the ICRP, Publication 50 Recommendations of the International Commission on Radiological Protection, International Commission on Radiological Protection. 2-9 CHAPTER 3 POTENTIAL EXPOSURE PATHWAYS 3.1 URANIUM AND ASSOCIATED NUCLlDES 3-2 3.2 POTENTIAL EXPOSURE PATHWAYS 3-3 3.3 RADON GAS AND ITS ASSOCIATED HEALTH RISK 3-7 3-1 3.1 URANIUM AND ASSOCIATED NUCLlDES The main source of radioactivity in the South African gold mining industry is naturally occurring uranium 1 metal contained in the underground ore body at a uranium (U308) grade2 of approximately 0.01-0.08%. Uranium-238 is the predominant parent of a long series of radionuclides which finally decays to the stable nuclide Lead-206 (Table 3-1): Table 3-1: Major isotopes in the Uranium series3 :.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.: :.: : :.:.:.:.:.:.:.:.:.:.:.:.: :.:.:.:.:.:.:.;.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:.:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::.:.:.: . 4.468x10" years 4.18 (77%) 4.15 (22%) 24.1 days 0.19 (65%) 0.10 (35%) L""" Pa 1.175 minutes 2.31 2.48x10" years 4.77 (72%) 4.72 (28%) 8.0x104 years 4.69 (76%) 4.62 (23%) 1622 years 4.78 (94%) 4.60 (6%) 3.825 days See table 3-2 3.05 minutes 5.99 (+99%) L'''Pb 26.8 minutes 0.65 L'''Bi 19.7 minutes 1.65 Ll"PO 164x10-4 seconds 7.69 (100%) 19.4 years 0.02 (81%) 0.06 (19%) 5.0 days 1.16 (99%) 138.4 days 5.29 (100%) Stable 1 Jansen van Vuuren et al (1995), Assessment of the Radiological Impact to the public from surface works on mines: Exposures from aquatic sources, Final Report GU9301, CSIR. 2 Atomic Energy Corporation of South Africa, Uranium in South Africa (1980-1990) 3 Cember H (1983), Introduction to Health Physics, Second Edition, Pergamon Press 85 - 85. 3-2 3.2 POTENTIAL EXPOSURE PATHWAYS Uranium and its decay products are found in varying concentrations throughout the gold mining process and are traceable throughout the process stream. This can be seen in the elevated uranium and radium concentrations in ore and the final slimes or tailings material". The initial underground mining process also liberates radon gas from the radium in the surface layers of broken rock. Although not considered the major radon contributor to the public, these underground radon concentrations pose the main radiation exposure risk to the underground worktorce" and are considered as a potential radiation source to public due to the air emitted from upeast ventilation shafts. The main potential exposure pathways considered in this assessment" were: Inhalation: • Inhalation of radon gas 222Rn, and its short-lived progeny from tailings dams, waste rock dumps and upeast shafts from underqround" • Inhalation of radioactive dusts containing long-lived alpha emitting nuclides, from mainly the tailings darns". 4 DeJesusAS M et al (1987),An assessmentof theRadium-226concentrationlevelsin tailingsdamsandenvironmental watersin thegoldanduraniumminingareasof theWitwatersrandA, tomicEnergyCorporation 5 Hazardassessmentreportsfor undergroundworkers,NuclearLicenceNL-57submissions,Councilfor NuclearSafety 6 JansenvanVuurenet al (1995),Assessmentof the RadiologicaIlmpactto the publicfromsurfaceworksonmines: Exposuresfromaquaticsources,FinalReportGU9301,CSIR. 7 Annalsof the ICRP,Publication65 (September1993),ProtectionagainstRadon-222at HomeandatWork, International CommissiononRadiologicalProtection 8 Annalsof the ICRP,Publication72 (September1995),Agedependentdosesto membersof the publicfromintakeof radionuclidesP: art5Compilationof ingestionandinhalationdosecoefficients,InternationaCl ommissiononRadiological Protection 3-3 • Ingestion or consumption of water potentially contaminated with radioactivity. a Ingestion of foodstuff potentially contaminated with radioactivity. External exposure: • External exposure to gamma radiation from tailings and waste rock dumps. The potential exposure pathways are described by the following interaction matrix'? and flow diagram (Figures 3-1 and 3-2): 9 Annals of the ICRP, Publication 72 (September 1995), Age dependent doses to members of the public from intake of radionuclides: PartS Compilation of ingestion and inhalation dose coefficients, International Commission on Radiological Protection 10 Licencing guide LG-1 032 Revision 0 (April 1997), Guideline on the assessment of radiation hazards to members of the public from mining and minerals processing facilities, Council for Nuclear Safety. 3-4 INTERACTION MATRIX: Source Terms ~ Exposure Pathways ~ Human Erosion Exhalation Run-off Seepage Erosion Exhalation Run-off Seepage Emission Seepage, discharge SeepageI I Deposition Deposition Consume Consume Uptake Figure 3-1: An interaction matrix indicating the major source terms and exposure pathways. 3-5 . /,.- .. --, _.~l II-'!-- 111""'; «I! J ',' .. -:.. .;... ~ ~ I!~'" - i .f ~"~4.lr ..[)Ol~__. .' I _',... :;Ijl.~,-".~"I _I.!~ .,u;;;fluma n ~ 1-1 t- ' .._~0);: IC-'"jj• ~ I, .. -11'11:: ;.LoL/1._ -- I ~' r •I ·it-· r-~..~ ~_~ _. ... i::' '.:;,. ~ - I Crops & Vegetation .L r .• r ':"11"1 I II 3-6 3.3 RADON GAS AND ITS ASSOCIATED HEALTH RISK The major contributor to the potential radiation exposures has previously been identified as radon gas emanating from tailing dams, waste rock dumps and upeast shafts from underqround". Radon-222 e22Rn) is the immediate decay product of Radium-226 in the uranium series of natural radionuclides. The potential exposure to radon gas is then also the focus of this assessment. Radon is a noble gas that decays to isotopes of solid elements, the atoms of which attaches themselves to condensation nuclei and dust particles normally present in air. 222Rn, with a half-life of 3.82 days, decays by alpha emission to Polonium-218. Polonium-214 decays to Lead-210 which has a half-life of 23.3 years, and which eventually decays to stable Lead-206. As radon is chemically inactive, radon gas is freely breathed in and out and being only slightly soluble in water (blood), it is the chemically active decay products such as lead, bismuth and polonium deposited on the tissue of the lungs that poses the risk of radiation induced cancer". The main decay properties of the short lived radon progeny is shown in Table 3- 2, indicating energies and yields of the proqeny": 11 JansenvanVuurenetal (1995),AssessmenotftheRadiologicaIml pactothepublicfromsurfaceworksonmines: Exposurefsromaquaticsources,FinalReportGU9301C, SIR. 12 HopkePH,Themeasuremenotf radondecayproductsin indoorairandtheirrelationshitpodose.Dept.ofChemistry, ClarksonUniversityN,Y. 13AnnalsoftheICRP,Publication65(Septembe1r993),ProtectionagainsRt adon-22a2tHomeandatWork, InternationaClommissioonnRadiologicaPlrotection 3-7 Table 3-2: Radon decay products Alpha Beta Gamma Radio- nuclide Half-life Energy Yield Energy Yield Energy Yield (MeV) (%) (MeV) (%) (MeV) (%) 222Rn 3.824 d 5.49 100 218pO 3.05 m 6.00 100 214Pb 26.8 m 1.02 6 0.35 37 0.7 42 0.30 19 0.65 48 .24 88 19.9 m 3.27 18 .61 46 1.54 18 1.77 16 1.51 18 1.12 15 164 us 7.69 100 d(days), m(minutes), s(seconds) The potential alpha energy of an atom in the decay chain of radon is the total alpha energy emitted during the decay of this atom to stable 21oPb.The potential alpha energy concentration of any mixture of short-lived radon progeny is the sum of the potential alpha energy of these atoms present per unit volume of air i.e. J m-3. The potential alpha energy concentration of any mixture of radon progeny in air can also be expressed in terms of the so-called equilibrium equivalent concentration of their parent nuclide, radon. The SI unit for the equilibrium equivalent concentration is Bq m-3. The equilibrium factor, F, is defined as the ratio of the equilibrium equivalent concentration to the activity concentration of the parent nuclide, radon, in air. In other words this equilibrium factor characterises the disequilibrium between the mixture of short-lived progeny and their parent nuclide in air in terms of potential alpha energy. The radiation exposure of an individual to radon gas is the time integral of the potential alpha energy concentration in air, or the corresponding 3-8 equilibrium equivalent concentration of radon to which the individual is exposed over a given period, normally calculated over one year. For most purposes it is adequate to use an equilibrium factor of 0.4 and an occupancy of 2000 hours per year at work or 7000 hours indoors (UNSCEAR, 1988)14. For outdoor radon the equilibrium factor may be higher (0.6-0.8). Radon occurs naturally in buildings and the workplace with widely varying concentrations". This makes it extremely difficult to distinguish between radon concentrations that should be treated as "natural background" and radon concentrations due to human practices where the benefits of the practice either offsets the radiation detriment, or not. This fact was also evident in the environment around the gold mines. The consequences of exposure to ionising radiation are best based on epidemiological studies of human populations. In this context, epidemiology is concerned with the establishment of statistical associations between exposures and health effects. These studies have established beyond any reasonable doubt that high levels of radiation is a causative agent of cancer in many organs in the body, including the lung. A quantitative association between radiation exposures and risk of contracting cancer at low levels is however more difficult. The main studies include the Life Span Study of the survivors of the atomic bombs at Hiroshima and Nagasaki as well as underground miners exposed to radon at work 16. 14 UNSCEAR (1988), Sources, Effects and Risks of Ionising Radiation. United Nations Scientific Committee on Effects of Atomic Radiation, 1988 Report to the General assembly, with annexes. United Nations, New York. 15 Radon concentrations in Klerksdorp homes, Anglogold Vaal River Operations, Nuclear Licence Report 16 Morrison H et al (1988), Cancer mortality among a group of fluorspar miners exposed to radon progeny. Am. J. Epideiol. , 128 3-9 The Life Span Study provides estimates of the cancer fatality coefficient for exposure, principally to gamma radiation, that is fairly uniform over the whole lung. The studies on miners provide information on the relationship between the incidence of fatal lung cancer and the concentration of radon progeny in the mining environment. There has also been many studies aimed at finding a correlation between the incidence of lung cancer and exposure to radon in dwellings. Some of these have shown positive correlation, but many have not. Most of these studies were geographical correlation studies that involved selecting two or more areas, some of high and some of low or average radon concentrations in dwellings. Geographical correlation studies are very difficult to interpret, even qualitatively, because of the presence of several serious confounding factors. One possible factor is the correlation of radon concentrations with other environmental features. Areas of high radon concentrations are often associated with rocky and hilly regions rather than in the river valleys and alluvial plains where industrial developments are likely to be concentrated. Thus, there could then be an inverse correlation between high radon concentrations and industrialisation. There is a likely correlation between lung cancer and industrialisation, probably associated with smoking. This makes it increasingly difficult to establish a quantitative relation between lung cancer and radon. Case control studies of radon in dwellinqs'" are not inconsistent with the mining studies, but most of them do not provide any quantitative data. At this stage even the ICRP continues to rely heavily on the data from epidemiological studies on miners, because of this lack of statistical power in the studies on dwellinqs". 17 Annals of the ICRP, Publication 65 (September 1993), Protection against Radon-222 at Home and at Work, International Commission on Radiological Protection 18 Schoenberg J B et al (1990), Case control study of residential radon and lung cancer among New Jersey women. Cancer Res. 50, 6520-6524 3-10 Due to the numerous uncertainties in radon epidemiology, ICRP has concluded that the use of the epidemiology of radon in mines is more direct, and therefor involves less uncertainty and is more appropriate than the indirect use of the Hiroshima and Nagasaki data. The fatality coefficients in ICRP 65 are thus based on the epidemiological studies on miners exposed to radon. In ICRP 65 the epidemiological evidence for the induction of cancer following inhalation of radon comes from several studies of underground miners, particularly uranium miners. The findings of these reports are summarised and reviewed in reports such as UNSCEAR (1986,1988), NRC (1988), IARC (1988) and ICRP (1991). Many of the studies are consistent with the linear non- threshold relationship between excess risk and cumulative exposure. If we consider lifetime risk from chronic exposure, the fatality probability coefficient for the general public could be somewhat larger than that for miners because of the inclusion of children in the population. This is however offset by the decreasing excess relative risk with time. For the mortality coefficient for cancer in general, ICRP uses a fatality coefficient of 5x1 0-2 per Sv for the public, a factor of 1.25 higher than that of workers 19. Based on comprehensive data on world-wide indoor radon concentrations, UNSCEAR (1988)20 adopted an arithmetic mean of 40 Bq m-3 with a geometric mean of 25 Bq m-3 and standard deviation of 2.5 Bq m-3. However elevated regional values ranging up to several times these values occur fairly widely and values of up to thousands of Bq m-3 have been found in houses in Finland21 and Sweden. 19 AnnalsoftheICRP,Publicatio6n5 (Septembe1r993)P, rotectioangainsRt adon-22a2tHomeandatWork, InternationCalommissioonnRadiologicaPlrotectio1n2-13 20 UNSCEAR(1988)S, ourcesE, ffectsandRisksofIonisingRadiationU.nitedNationsScientificCommitteoenEffectsof AtomicRadiation1,988ReporttotheGeneraal ssemblyw,ithannexesU. nitedNationsN, ewYork. 21 Castren0 (1987)D, ealingwithradonindwellingsth: eFinnishexperienceP,roceedingosfthesecondInternational SpecialitCyonferencoenIndoorRadonA, irPollutionControAl ssociatio4n5-56 3-11 UNSCEAR (1988) assumes occupancy factors of 0.80 indoors and 0.20 outdoors for world-wide calculations. These occupancy factors have been challenged by some European studies such as the UK22 and Sweden where indoor occupancy goes up to 90%. However, the rounded factor of 0.80 corresponds to 7000 hours per annum indoors and serves as a fairly representative occupancy factor. ICRP defines a radon-prone area as being an area where the radon concentration in buildings is likely to be higher than the typical radon concentration of the country as a whole. Such definition of a radon prone area should however be related to a number of dwellings per area, and not as individual radon prone dwellings. This is important as high radon concentrations could be recorded in a few buildings or houses without it being part of a so-called radon-prone area, and visa versa. From the proposed remedial and preventative measures for reducing high radon concentrations indoors, the removal of solid material such as contaminated soil is only considered in extreme cases and the focus is rather placed on engineering controls in the construction of the dwellings in the radon-prone area23. This is an important consideration in the gold mining areas where the perceived high source of radon gas is the tailings dams and upeast shafts and not necessarily the underlying soil. Remedial action is almost always justified if the continued annual effective dose exceeds 10 mSv. For simple remedial measures the action levels could be reduced, however considering the fact that a reduction of a factor of 5 to 10 would reduce the action level to a value well below the dose from natural background sources. In ICRP 65 the range of action levels is usually in the order of 3-10 mSv/a, which relates to a radon concentration of between 200 to 600 Bq m-3 (occupancy of 7000 hours and equilibrium of 0.4). 22 Brown L (1983), National radiation survey in the UK: Indoor occupancy factors. Radial. Prol. Dosimetry 5(4), 203-208 23 Annals of the ICRP, Publication 65 (September 1993), Protection against Radon-222 at Home and at Work, International Commission on Radiological Protection 14-15 3-12 Differences in action levels for existing dwellings and future proposed development do not differ very much. Here the emphasis should be on areas with higher radium-bearing wastes, such as tailings material, calcine spills and redundant plant foundations. Any proposed remedial action, either voluntary or enforced by a regulator should be weighed against the perceived socio-economic benefits as well as the priority of all the prevailing health risks in the area considered. From a public health perspective, radon-induced lung cancer risk could be a relatively minor importance when compared to smoking, as was indicated in recent Canadian studies/". Investigations are ongoing about the effect of low level radiation on the human body and several studies'" yield results that seem to be contrary to the linear non-threshold theory. A number of international experts" are convinced that exposures to low level radiation, specifically radon gas, could actually be beneficial to the human body. In an American study, Jagger (1998)27 reported that the age-adjusted overall cancer death rate is 1.26 times higher in the Gulf Coast of the USA than in the Rocky Mountain states, although the natural background radiation levels are 3.2 times higher in the last mentioned. The average radon gas concentrations in the living areas of homes in the Gulf Coast are 18.5 Bq m-3, compared to the 96 Bq m-3 in the Rocky Mountain states. 24 Ayotte Pierre (1998), Indoor exposure to 222Rn: A public health perspective, Health Physics 75(3): 297-302 25 Jawarowski Z (1995) Beneficial Radiation. Nukleonika 40, 3-12. 26 Cohen B L (1997), Test of the linear no-threshold theory of radiation cacinogenesis for inhaled radon decay products, Health Physics 58 (157-174) 27 Jagger John (1998), Natural background radiation and cancer death in Rocky Mountain states and Gulf Coast, Health Physics 75(4): 428-430 3-13 It is possible that factors such as smoking, poverty, or environmental pollution could contribute to the differences in cancer mortality, but the large factor of disproportion (4.0-7.5) strains credulity that such factors could reverse this negative correlation. Present scientific evidence on the effects of low doses is inconclusive with contradicting views and it may be that the natural background radiation levels (20-100 Bq rn') are too low to be a significant cause of cancer mortality, or that there is a non-linearity of the dose-effect curve, or even hormesis". 28 Pollycove M (1988), the rise and fall of the linear no-threshold (LNT) theory, Annual Congress of the South African Radiation Protection Association. University of California, San Francisco. 3-14 CHAPTER4 SOURCE TERM DETERMINATION 4.1 RADON FLUX MEASUREMENTS 4.1.1 CLOSED BOX METHOD 4-7 4.1.2 DIFFUSION TUBE METHOD 4-13 4.1.3 PASSIVE EaPERM FLUX MEASUREMENTS 4-17 4.1.4 DYNAMIC FLOW-THROUGH METHOD 4-22 4-1 4.1 RADON FLUX MEASUREMENTS The main sources of radon gas have previously been identified as tailings dams, waste rock dumps and upeast air from underground workings. The radon concentration in upeast air was measured simply by placing radon gas monitors in the upeast draft. A maximum measured concentration of 3000 Bq m-3 for the upeast shafts was used to calculate a conservative discharge rate for the dispersion modelling. Due to their size and the varying radium e26Ra) concentrations in the tailings dams 1 and waste rock dumps, it was extremely difficult to accurately determine the radon emanation rate from the dams. There are a number of factors that influence the emanation rate or flux from a tailings dam. If we consider a tailings dam with n layers of material, then the radon flux at the surface of the dam can be described as follows2: 4-1 Where: Ft Radon flux at the surface of the dam (Bq m-2 s") R Radium content of the tailings material (Bq kg·1) p Bulk density (kg m") E Emanation coefficient D Diffusion coefficient (m2 S-l) 1 Slimes dam survey results (1996), Nuclear Licence NL-57, Appendix III 2 IAEA Technical Reports Series No 333, Measurement and calculation of radon releases from uranium mill tailings, VIENNA,1992 4-2 X Thickness of a layer (m) A. Radon decay constant (S·1) The influence of some of the major parameters on the radon f1ux3are described in Figures 4-1 J 4-2 and 4-3: II .7...... Radon Flux vs Radium (226Ra) Content -..- t • " t-o ,.J »>. " -"'1 ~... I'· re "11- "'J". ' ..0.5 1-;..... I.... ... -i ~ ., ! 1 ,'.. .i.-·' ~"'_r .,.:.. ~. ~ ... '_ l" 1.·. .1. ~ T"" -, • IJ .\ " • ~ . 0.4 , I ,_ • J. I .. _ \' I ~ l- I. JL... I .,~ =I<":' - I),.-I. 'lJ • ~:. "'" , '.J Iii: Nil! 0.3 .. 1 .....l I .,.. ! &• • ,LJ+=-11 I••• I ". ,r::: 'E -tiI.I il.o ' I " J 1 ... ..",.,~r, • .1 'i g 0.2 :I r"B._-, •• 1 rl" s0::- \: -. -: , 0.1 ,- . o 0.5 1.5 2 2.5 3 3.5 Radium (Bqlg) • I ~,,." I, Figure 4-1: Radon flux vs 226Ra 15 20 35 5011Moisture (Weight %) ,,.. Figure 4-2: Radon flux vs moisture content 31ntercomparison of radon exhalation measurements (March 1998), Council for Nuclear Safety Report, (48CB0180) 4-3 i ~"lI ~ _ I- : ~ - I ". I ~ I I Radon Exhalation vs Soil Porosity L I, I 0.00 >oe - 0.075 _::I 00:-fil u.. ",' § 'E; 0.07 0' ,I"g ca m a: - 0.065 I' 1 ,..J-, -, • ._~j , ••, ........-: ... - ...J.. (j,;_ 0.06 0 IL ',. , 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 ~ i-I,::' 5011Porosity '/ {'.' .. Figure 4-3: Radon flux vs porosity One of the major parameters is the emanation coefficient (E) in Equation 4-1 that also shows a linear relationship with the flux from the surface of the dam: .ol _,.l f oil :~~I_I I ):f"''':._;~- Radon Exhalation vs Emanation Coefficient ........., . • ,L_,~ 0.3 I' 0.25 >oe- .2 OO:-fII 0.2 LL ~. " I § E; 0.15 "g 0' ;},!!!. 0.1 0.05 O~~-'r.----.----.-----r----'-----'----'----''---~ o 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 Emanation Coefficient .. Figure 4-4: Radon flux vs Emanation Coefficient Due to the potential influence of all the parameters in Equation 4-1, especially the emanation coefficient, it was essential to determine the flux from the tailings dam by in situ radon flux monitoring techniques, 4-4 The influence of the flux measurement itself on the radon flux from the tailings dam is a major consideration when embarking on any such experimentsv". Due to the uncertainty regarding the accuracy of flux measurements, it was decided to explore as many techniques as possible to ensure that at least the appropriate range of flux values were used in the dispersion modelling exercise. There are mainly three approaches to radon flux measurement: • By using equations describing flux from a surface e.g. Equation 4-1, and measuring just the 226Ra content of the material and assuming theoretical values for the other parameters, the radon flux may be calculated. • A second similar approach is to take a physical sample of the material and then determine the flux, using the 226Ra content and laboratory measured values for as many of the remaining parameters as possible. • The third basic technique is the in situ measurement of flux by means of some kind of "vessel" i.e. monitor, ionisation chamber, etc. placed on the surface of the tailings material and the radon flux deducted from the radon concentration inside the vessel. The different flux measurement techniques employed during the assessment are discussed in more detail in the next sections. Prior to embarking on the study a contamination survey was conducted of 27 tailings dams in the area to determine the relative radioactivity concentrations of the different darns". 4 SamuelssoCn(1987)A, criticaal ssessmeonftRadon-22e2xhalatiomneasuremenutsingtheclosed-camnethod, LundUniversityS,weden. 5 JonasseNn(1983)t,hedeterminationfradonexhalatiornates,HealthPhysic4s5(2),369-376 6 Slimesdamsurveyresults(1996)N, ucleaLricenceNL-57A, ppendiIxII 4-5 The highest contamination areas on the dams were identified using a hand-held beta/gamma contamination monitor/ to survey the surface area of the dam by trisecting the dam in different directions. Samples of the tailings material were taken at these "hot-spots" and analysed for 226Ra,the parent nuclide of radon gas in the tailings darns". The distribution of these maximum 226Raactivity concentrations is as follows: Average 226Ra concentration of 1 Bq/g 1 2 3 4 5 6 7 8 9 1011121314151617181920 212223 2425 2627 Tailings dam Figure 4-5: Highest 226Raconcentrations in tailings dams Based on the above distribution the flux measurements were done on tailings dams with a 226Raactivity concentration of about 1 Bq/g. Only dry, dormant dams were considered as this represents a worst case scenario in terms of potential radon f1u~. It was further assumed that most of the tailings dams would be dormant and dry within the next 30 to 50 years 10. 7 Training Manual prepared and issued by the Technical Services of the Chamber of Mines of South Africa (19921),34. 8 Isotopes were analysed by -y,a-spectroscopy, Atomic Energy Corporation. 9 IAEA Technical Reports Series No 333, Measurement and calculation of radon releases from uranium mill tailings, VIENNA, 1992 10 Environmental Management Programme Report (1997V)ersion 4,Free State Consolidated Gold Mines (Operations) Limited 4..6 Three different tailings dams were considered. For inter comparison purposes radon flux measurements were also conducted on a pyrite dam, with much higher 226Raconcentrations, as well as limited measurements on normal garden soil. 4.1.1 CLOSED BOX METHOD The radon concentration inside a vessel placed on a surface emanating radon gas 11 is described in Figure 4-6: Radon concentration inside a closed vessel .co~... _ C QI QI > Uc0n .- o - i / c-~ o "'C ca 0:: Time (relative) Figure 4-6: 222Rninside a closed vessel placed on a tailings surface In Figure 4-6 a closed or semi-closed vessel is placed on the surface of a tailings dam at time to., with equilibrium being established at k This state of equilibrium is also described as the concentration at which the diffusion rate into the vessel is equal to the rate of "back diffusion". This "back diffusion" is the effective result of the radon concentration gradient between the vessel and its surroundings, possible leakage from the vessel and radon decay inside the vessel. 11 Aldenkamp RJ et al (1990), An assessment of a method for in situ radon exhalation measurements, Kernfysich Versneller Instituut, Croningen, 4 (17-28) 4-7 The radon concentration inside the vessel may be described by Equation 4-3, following from Fick's first law (Equation 4-2): F(t)=~'n:>VL"C(t)1 4-2surface ec; F(t)A at V - ARn Cean - A/eak Cean 4-3 Where: F(t) flux through the surface (Bq m-2 S-1) A surface area of the material covered by the vessel (m2) V volume of the vessel (m") Ccan radon concentration in the can (Bq m-3) and where the diffuse leakage of radon from the vessel is proportional to the radon concentration with the rate constant "'leak. Consider the radon concentration in the vessel at time to, as described by Figure 4-6. The radon concentration inside the vessel at to would be the same as that outside the vessel. Thus at time t = to or t ';::j to the radon concentration inside the vessel would be Ccan(to). If we consider the initial rate of change (slope) of the radon concentration inside the vessel, the flux F(t) would be directly proportional to this initial rate of change and the flux can be determined by: aCean at 4-4 ru.« o )=-vAx (a___c_a_Et!!!_ )-C (t) 4-5can 0 4-8 By continuous measurement of the radon concentration inside the vessel with known dimensions, the net flux can be determined by calculating the initial slope of the graph in Figure 4-6. In the assessment, this method was used by placing a closed and sealed glass box (300x300x450mm) tightly on the surface of a tailings dam and measuring the 12 radon concentration inside the box at 10-minute intervals with an Alphaguard Radon Gas Monitor. The experimental set-up is described in Figure 4-7. Glass box placed on tailings dam with radon monitor inside Tailings dam Figure 4-7: Experimental set-up for closed box experiment By plotting the radon concentration at 10-minute intervals, flux calculations were then based on the initial rate of change of the radon concentration inside the box, according to Equation 4-5. 12 AlphaGUARD Professional Radon Monitor (1997), Operating Manual. Genitron Instruments, Frankfurt, Germany 4-9 RESULTS The following results were obtained with the closed box method: Garden soil 1500 : ,. ,I, i . ,.,' ,:., .... '.- T""= ' • -:--, 1 r"T! " ... '," I _.- ~1'- I!>J r ~ 'j ~--., '1 ..-·----" _ol '" ·1".II""- I-!. 1000 .... .,~.....~"r I \ r.• ?-::.~," .. ," , I" --'fI~~':r-•:'I~ .: J I11" ti.... n 800 'l1li ~ .. 4 r ~ -.,,I rr»» '...I.,....... ,• -", ~'\1 • • t"'1 "1 e; • '11- I-A600 .1 ~, C" III ,l" 400 3 4 5 10 minute Intervals Figure 4-11: Initial slopes for different tailings dams and normal soil 4-11 Table 4-1: Closed box flux measurement results Material Location Radon Flux (Bq m-2 S-1) Soil Garden soil 1 0.012 at ±0.04 Bq/g 226Ra Garden soil 2 0.017 Tailings Dam 1 0.050 at ±1.0 Bq/g 226Ra Dam 2 0.044 Dam 3.1 0.060 Dam 3.2 0.047 Average 0.050 STD 0.007 Pyrite Pyrite dam 0.640 at ±10.0 Bq/g 226Ra Based on the flux measurements and the 226Raconcentrations for soil, tailings material and pyrite, the following graph indicates to some extent a linear relationship between the radon flux from a surface and the radium e26Ra) concentration of the material as theoretically expected": 1'· ..... 'i".! - I....... t .. c. _ .' r-\/ ; _~I" Radon flux vs Radium content , - .~I .....,,.... l- I; 0.6 C" ID ;- 0.4 :::J Li: co 0.2 "C ca 0::: 10 226Ra concentration (Bqlg) Figure 4-12: 222Rnflux vs 226Racontent Based on the above graph one could deduct a relationship of 0,07 Bq m-2s' per unit activity concentration (1 Bq/g) of radium, all other parameters being equal. 13 IAEA Technical Reports Series No 333, Measurement and calculation of radon releases from uranium mill tailings, VIENNA, 1992 4-12 4.1.2 DIFFUSION TUBE METHOD In the so-called diffusion tube method14,15usedby the consultants PARC Scientific''', a sample of the tailings material is obtained and sealed to preserve the moisture content. A sub-sample of the material is then compacted into a short diffusion tube, which is attached to a longer tube to provide a well-defined air space above the sample surface. Another similar but larger sub-sample is then compacted into a longer tube and connected to a diffusion tube with the same dimensions as the first. The two sub- samples thus have the same geometry of air space above the compacted material as illustrated in Figure 4-13: Similar geometry of air space above material z Compacted material Figure 4-13: Experimental set-up for the diffusion tube method 14 IAEA Technical Reports Series No 333, Measurement and calculation of radon releases from uranium mill tailings, VIENNA,1992 15 Rogers V C et al (1980), Characterisation of uranium tailings cover materials for radon flux reduction, NUREG/CR-1081 16 Strydom R, PARC Scientific Technical Documents, PARC-002l95;PARC-OO4I95;PARC-EXMOD-OO1195; PARC- EXPAR-001194 4-13 The material was then compacted to between 1300 and 1600 kg m-3, the bulk density for tailings material as determined from literature 17. After compaction the tubes were sealed for up to fifteen days for the radon exhalation to establish equilibrium. The tubes are then rapidly opened and radon gas etched track monitors (RGM's) inserted into the air space of each, after which the tubes are again sealed for a period of 4-5 days. These radon monitors record the radon gas concentration as an integrated concentration over the exposure period. The geometry of the diffusion tubes is such that the exhalation of radon from the two sample surfaces can be modelled by one-dimensional diffusion theory. The generation and transport properties of the sample material determine the rate at which radon will be exhaled from the surface of the material. This diffusion though the surface of the material can be described by the following one- dimensional diffusion equation (Equation 4-6): 2 D 0 C _ A.C+ RpA.8 = 0 4-6 OZ2 P Where: D effective diffusion constant (m2 S-1) C interstitial radon concentration (atoms m-3) A radon decay constant (2.097x1 0-6 S-1) R Radium content (Bq kg-1) z co-ordinate perpendicular from the surface into the material 17 Macphail G. (1995) Metago Environmental Engineers. Personal Communications. 4-14 The solution of Equation 4-6 is given by: C(z)=C (1- tanh-I(z/L)) 4-7 eo ktanh-I(L/z) Where = radon concentration at infinite depth of the material C(z) = radon concentration at depth z into the material L = diffusion length = (DIA)'!. The radon flux at the surface is then given by: F=_DdC(Z)1 4-8 dz Z~Z Where Z is the z co-ordinate at the surface of the material. Equations 4-7 and 4-8 then form the basis for modelling the radon flux from the surface of the materia!". 18 Strydom R, PARC Scientific Technical Documents, PARC-004/95: Modelling of radon exhalation rate and resulting source term from tailings impoundments and sand dumps. 4-15 RESULTS The following results were obtained by PARe Scientific on one of the tailings dams considered in the assessment, using the diffusion tube method: Table 4-2: Diffusion tube flux measurement results 3.9x10-7 0.211 9 10-7 0.191 3 3.4x10-7 4 0.237 5 5.2x10-T 0.183 4-16 4.1.3 PASSIVE E-PERM FLUX MEASUREMENTS Passive E-PERM flux monitors 19 were used to measure the radon flux from the surface of a tailings dam without interfering with the physical nature of the slimes rnaterlar". The electret ion chamber is a passive integrating ionisation monitor consisting of a very stable electret mounted inside a small chamber made of electrically conducting plastic. The electret is a charged Teflon disk, which serves both as a source of electrostatic field and as a sensor. Radon gas passively diffuses into the chamber and the alpha particles emitted by the decay process ionise air molecules inside the chamber. The ions produced inside the chamber collect on the electret and cause a reduction of its surface charge or potential. The reduction in charge or change in voltage is a function of the total ionisation, or if calibrated accordingly, the integrated radon concentration over the exposure period. The E-PERM flux monitor consists of an H electret ion chamber that has been modified with an electrically conducting diffusion window made of Tyvek. The chamber is vented by four outlets that ensure that the radon does not accumulate in the chamber. Thus, when the flux monitor is placed on the surface of the tailings dam the radon enters through the Tyvek barrier and exits through the vents. The semi-equilibrium radon concentration established inside the chamber is representative of the flux from the surface. Because of the equilibrium between the radon from the ground and the radon in the outside air through the vents, the flux from the tailings surface is not disturbed. The semi-equilibrium radon concentration is representative of dynamic flux from the surface. The discharge rate of the electret is a measure of the radon flux. 19 E-PERM® System Manual, Radon & Radiation Measurements, Rad Elec Inc. 20 Stieff Rand Kotrappa P (1996), Passive E-PERM radon flux monitors for measuring undisturbed radon flux from the ground, International Radon Symposium, II - 1.1. 4-17 The E-PERM flux monitors have been calibrated on well characterised radon flux beds at CANMET21 (Canada), which are known to produce a radon flux of 7.7 ±1.1 pCi m-2 S-1 (0.285 ± 0.04 Bq m-2 S-1). As the electret chambers are prone to gamma induced ionisation, corrections were made for the gamma background by placing duplicate flux monitors on the tailings dam which had been sealed with steel plate to prevent radon from the surface to enter through the Tyvek window. The experimental arranqernenr? is described in Figure 4-14: E-Perm Flux monitor wifliyvek window which transparent to radon emanating from the tailings dam E-Perm flux monitor with steel plate prevent radon entering the chamber determine gamma background 'c:;{ ,Q, Tailings dam Figure 4-14: Experimental set-up for E-PERM flux monitors The net voltage drop after gamma background correction provided a measure of the radon flux from the tailings dam surface. 21 Bigu J, CAN MET Elliot Lake Laboratory (National Reference Standard), Ontario, Canada. 22 E E-PERM" System Manual (1994), Radon & Radiation Measurements, Rad Elec Inc. Part 1110 Measurement of undisturbed flux from the ground. 4-18 It is important to note that the discharge rate of the electret in electret ion chambers is not the same for unit flux for all operating voltages of the electret. The result must thus be multiplied by a linearity correction coefflcienr" given by: LLC = 0.7727 + 0.0004568 x {( I + F )/2} 4-9 Where I and F are the initial and final voltage readings of the electret. RESULTS The following results were obtained with the E-PERM flux monitors: Table 4-3: E-PERM flux measurement results (1) Dam 1 1 6.5 0.099 2 6.5 0.0006 3 6.5 0.056 4 6.5 0.031 0.046 0.034 Following the first set of results, the flux monitors were slightly modified by placing a flat steel ring-plate around the base of the monitor and sealing it tightly with silicon-gel to prevent any radon from escaping between the ring-plate and the monitor. This modification was necessary to ensure that the monitor could be tightly placed on the uneven tailings dam surface without damage to the monitor or leakage between the monitor and the tailings dam surface. 23 E E-PERM® System Manual (1994), Radon & Radiation Measurements, Rad Elec Inc. Part II 10 B Page 2. 4-19 Better correlation were obtained amongst the individual flux monitors, following this modification: Table 4-4: E-PERM flux measurement results (2) 2 6 0.008 3 6 4 6 0.014 5 6 0.023 6 6 0.008 7 6 0.028 8 6 0.037 0.021 0.013 Table 4-5: E-PERM flux measurement results (3) Dam 3.1 1 8 0.021 2 8 0.035 3 8 0.025 4 8 0.016 5 8 0.025 6 8 0.075 7 8 0.016 8 8 0.022 9 8 0.022 0.029 0.018 4-20 Due to the large error as indicated by the standard deviation the experiment was repeated on the last tailings dam, but the exposure period was extended to 27 hours to ensure that a true equilibrium of the radon concentration is reached. This proved to be a critical aspect of the monitoring technique as the E-PERM Flux Monitor acts as a vented closed-box requiring a relatively long time for equilibrium to be established. As expected, better correlation was established amongst the different sets of monitors deployed on the tailings dam: Table 4-6: E-PERM flux measurement results 27 3 27 0.025 4 27 0.026 5 27 0.046 6 27 0.024 7 27 0.022 8 27 0.041 9 27 0.02 0.031 0.009 4-21 4.1.4 DYNAMIC FLOW-THROUGH METHOD The dynamic flow-through method for measuring undisturbed radon flux from tailings dams was based on the dynamic method described in the Electret Operating Manual (1994l4 and Livingstone & Jester (1990)25. In this assessment, the E-PERM radon gas monitors were just substituted with and Alphaguard radon monitor. This was done to more accurately determine the conditions inside the vessel at shorter intervals. A graph of the radon gas concentration inside the vessel clearly indicates when steady state equilibrium is achieved inside the vessel. This value represents the average radon gas concentration required to calculate the flux from the tailings dam. The radon flux from the tailings dam (J) was calculated based on the measurement of the radon concentration (R) inside the box with known area (A) and air flow rate (F). This is determined assuming that (R) is the steady state radon concentration inside the box, that the flow rate (F) is constant and that the detector measures a representative radon concentration inside the box. This condition is described by the following equation: RxF J=-- 4-10 60xA Where: J Radon flux (Bq m-2 S-1) R Average radon concentration inside the box (Bq m") F Flow rate (rrr' min") A area of the tailings dam surface covered by the box (m2) 60 conversion factor (sec mln") 24 E-PERM® System Manual, Radon & Radiation Measurements, Rad Elec Inc. 25 Livingstone J Vet al (1990) Annual Meeting of American Nuclear Society, Volume 61 Pages 1-39 4-22 In Equation 4-10 the radon balance is established i.e. radon in (JxA) = radon out (RxF). In the experiment, this method was used by placing a closed and sealed glass box (300x300x450mm) tightly on the surface of a tailings dam. A pre-calibrated air pump was attached to an outlet in the box, with an inlet to the outside air on the other side of the box. The radon concentration inside the box was then measured at 1O-minute intervals with an Alphaguard26 Radon Gas Monitor. Glass box placed on tailings dam with radon monitor Free airflow inlet inside Calibrated airflow from outside air outlet of 0.36 I/min Tailings dam Figure 4-15: Experimental set-up for dynamic flow-through method The surface area of the box was 0.126 m2 and the flow rate calibrated at 0.36 I min". 26 AlphaGUARD Professional Radon Monitor (1997), Operating Manual. Genitron Instruments, Frankfurt, Germany 4-23 The radon concentration inside the box is described by Figure 4-16. I _. Dynamic method I(_ • I .......1 _ '. 400 .., E 300 mtT C 200 o -g 100 0..:.:.:.. I· o l - 10 I II ',' _ I 20 30 40 ~ r "1 10minute intervals J , Figure 4-16: Radon concentration inside the box in the dynamic flow through method The average radon concentration when steady state equilibrium is achieved was calculated from the graph and the radon flux calculated as 0.014 Bq m-2 S-1. Relative air pressure II I 400 (l- • I cI • '1 ... , J .., I I I • E 300 tT m -Radon C 200 I ~ o J Ir" -- Ret lW PresSlI'e .~"..... 100 10minute intervals Figure 4-17: Radon concentration inside the box vs the relative air pressure inside the box 4-24 The constant air pressure inside the box (Figure 4-17) confirms that no additional leakage of air into or out of the box occurred during the experiment. Due to a heavy downpour of rain the days before the above results were obtained, the experiment was repeated to prevent any potential reduction in the radon flux due to the high humidity of the tailings material. Both the closed box method and the dynamic method was used, consecutively at the same sampling location. The whole experiment was repeated again the next day. The following results were obtained: , ~T • ol. ill a.: < • 14' : ~ I'I~ . Dynamic Steyn 6.1 r·' .... 800 .., E 600 mti- - C 400 .~ II o " -,(..}.._200 I· 20 30 40 - - ..... -- 10minute intervals I • ~ :'1 Figure 4-18: Dynamic method on dam Steyn 6.1 1- .... -' : .. ",.. I .... ' I '-. Dynaml .c Steyn.62 1u·P... ' ~_ ~rJ - I ~-.:c1 ~,., .. , I' I C ..•.I.J~~ .-r...I:~LI_i.'. 800 .....' I... - -) I .. .., ...,...I 1_I.i"1i:o.: IJ - - • ~- I l:j(c_.-1" II E 600 mti- "-,-~,".- C 400 o -..g. 200cr:: . 10 minute intervals Figure 4-19: Dynamic method dam Steyn 6.2 4-25 Table 4-7: Dynamic method vs Closed Box method Rate of change / slope (Bq m-3 per 10min) 92 82.7 Flux (Bq m-2 15- ) Ll\/<,r<:>r,Q radon concentration inside box (Bq m-3) 700 516 Pump flow rate (I/min) 0.36 0.36 Flux (Bq m-2 15- ) By inter-comparing the different radon flux measurement techniques, the following was found": Table 4-8: Inter-comparison of flux measurement techniques 0.03 - .05 Dynamic Method 0.025 - O. Diffusion Tube Method 0.211 *Theoretical Calculation 0.245 *The according to Equation 4-1, assuming values for the other parameters. It is to be expected that the diffusion tube method would give approximately the same answer as the theory predicts as it follows from an assumption that all the parameters are as per the theory. In practice however, the sedimentation of the 27 Intercomparison of radon exhalation measurements (March 199B), Council for Nuclear Safety Report, (4BCB01BO) 4-26 wet slime causes different values of compaction, some surfaces being rock hard whereas others may be sandy. The E-perm and closed box methods must be the considered as the preferred methods as no assumptions on the physical properties of the slime material are made. These methods merely measure the radon entering the collectors from the tailings. It is however clear from the results obtained that radon flux from tailings dams is very difficult to accurately determine. All the methods employed during the assessment has some associated degree of uncertainty, either due to assumptions made or due to the influence of the measurement technique on the radon flux parameters. Because of these uncertainties and the fact that the maximum radium concentrations of the tailings dams in the Free State were as high as 3.0 Bq/g, a value of 1 Bq m-2 5-1 was used as a conservative radon flux value in the dispersion modelling exercise. 4-27 CHAPTER 5 MODELLING 5.1 RADON DISPERSION MODELLING 5-2 5.1.1 BRIEF HISTORY OF THE ISC MODELS 5-2 5.1.2 THE GAUSSIAN EQUATION 5-3 5.1.3 SHORT-TERM AREA SOURCE MODEL 5-4 5.1.4 DISPERSION MODELLING OVERVIEW 5-5 5.1.5 ISC SHORT-TERM MODEL 5-5 5.1.6 ISC3 PARAMETER LIMITS 5-6 5.1.7 REGULATORY APPLICABILITY 5-6 5.1.8 REGULATORY DEFAULT OPTION 5-7 5.1.9 METEOROLOGICAL DATA 5-7 5.1.10 VALIDATION OF THE BREEZE ISCST3 MODEL - 5-9 5.1.11 MODELLING RESULTS 5-10 5.2 WATER DOSE MODELLING 5-12 5.3 DUST MODELLING 5-20 5-1 5. MODELLING 5.1 RADON DISPERSION MODELLING This section provides a summary of the computer programmes, input parameters such as source term data, receptor data and meteorological data, as well as a short validation for the modelling programs used in modelling the dispersion of radon gas emanating from the tailings dams, waste rock dumps and upeast shafts to the environment. 5.1.1 BRIEF HISTORY OF THE INDUSTRIAL SOURCE COMPLEX (ISC) MODELS The ISC Short Term area source model' is based on a numerical integration over the area in the upwind and crosswind directions of the Gaussian point source plume formula. Individual area sources may be represented as rectangles with aspect ratios (length/width) of up to tu to 1. In addition, the rectangles may be rotated relative to a north-south and east-west orientation. Note that for the size and shape of the individual area sources, the only requirement is that each area source must be a rectangle. Dividing an area source into multiple rectangular areas simulates an irregular shaped area. Because of the flexibility in specifying elongated area sources with the Short Term model, up to an aspect ratio of about iOta 1, the ISCST area source algorithm may also be useful for modelling certain types of line sources. To shorten the processing time due to a large number of sources, an irregular shaped source was modelled by a rectangular source totally enclosing the original source. 1 U S Environmental Protection Agency (September 1995), User's guide for the Industrial Source Complex (ISC3) Dispersion Models, Volume II - Description of Model Algorithms, Office for Air Quality Planning and Standards, Emmisions, Monitoring, and Analysis Division (EPA), North Carolina. 5-2 This artificial enlargement of the source leads to an over estimation of the potential radon dose. This conservative approach is preferred to complex groups of small sources approximating the irregular source. The ground-level concentration at a receptor located downwind of all or a portion of the source area is given by a double integral in the upwind (x) and crosswind (y) directions. The user assigns the effective emission height, being the physical release height. This was set equal to the physical height of the source of emissions, above local terrain height. For example, the emission height of a tailings dam is the physical height of the tailings dam. 5.1.2 THE GAUSSIAN EQUATION The ISC short term model uses a steady-state Gaussian plume equation" to model emissions from sources. For a steady-state Gaussian plume, the hourly concentration at downwind distance x (metres) and crosswind distance y (metres) is given by Equation 5-1: OK VD y X exp -0.5 - 2] 5-1 2m',cT,CJ, [ (CJ .. J Where: Q pollutant emission rate (mass per unit time) K scaling coefficient to convert calculated concentrations V vertical term D decay term standard deviation of the lateral and vertical concentration distribution (m) Us mean wind speed (m S-1) at release height 2 Petersen W B at al (1987), Users guide for PAL 2.0 - A Gaussian-Plume Algoritnm for Point, Area, and Line Sources, EPA/600/8-87/009, U S Environmental Protection Agency, Carolina, USA. 5-3 The vertical term includes the effects of source elevation, receptor elevation, plume rise and limited mixing in the vertical. The x-axis is positive in the downwind direction, the y-axis is crosswind (normal) to the x-axis and the z- axis extends vertically. Fixed receptor locations are converted to each source's co-ordinate system for each hourly concentration. The hourly concentrations calculated are summed to obtain the total concentration produced at each receptor by the combined source emissions. 5.1.3 SHORT-TERM AREA SOURCE MODEL Individual area sources may be represented as rectangles with aspect ratios (length/width) of up to 10 to 1. The rectangles may be rotated relative to a north-south and east-west orientation. The ground-level concentration at the receptor located downwind of all or a portion of the source area is given by the double inteqraf in the upwind (x) and crosswind (y) directions as: z = QIIK f__!!2_(f expr-O.S(LJ2 }j)}x: Znu S-2CJyCJ z y CJy s x With the effective emission height being the physical release height. This should be set equal to the physical height of the source of emission above the terrain height. In this instance the release height of the tailings dam is the physical height of the tailings dam. The integral is not defined for receptors inside the source. 3 Environmental Protection Agency (1992), Sensitivity analysis of a revised area source algorithm for the Industrial Source Complex Short Term Model, EPA-454/R-92-015, U S Environmental Protection Agency, Carolina, USA 5-4 5.1.4 DISPERSION MODELLING OVERVIEW The ISCST3 computer-modelling prcqramrne" was used to model the dispersion of radon from radium sources. This suite of programmes is based upon the U.S. Environmental Protection Agency (EPA) ISCST3 and ISCl T3 models and is nothing more than a user friendly software tool to manipulate input data. The modelling itself is still done according to EPA ISCST3. The ISCST3 and ISCl T3 models are designed to estimate pollutant concentrations or deposition from an industrial source complex. Both models predict pollutant concentrations from continuous point, area, volume, and open pit sources. These versatile models enable one to estimate concentrations from virtually any type of source emitting a non-reactive pollutant. There are two versions of ISC3, a short-term model (ISCST3) and a long-term model (ISCl T3). The models differ in the averaging times available for calculation, available terrain and deposition options, and the format of input meteorological data. 5.1.5 ISC SHORT-TERM MODEL The Industrial Source Complex (ISC) Short Term model provides options to model emissions from a wide range of sources that might be present at a typical industrial source complex. The basis of the model is the straight-line, steady-state Gaussian plume equation, which is used with some modifications to model emissions from stacks, storage piles, etc. Emission sources are categorised into four basic types of sources, i.e., point sources, volume sources, area sources and open pit sources. 4 Computer Software Package, Shareware on Internet, EPA ISCST3 5-5 The algorithms used to model each of these source types are modified to account for both simple (flat) terrain and complex terrain (significant elevations in sources and receptor points). The ISC short term model accepts hourly meteorological date records to define the conditions for plume rise, transport, diffusion, and deposition. The model estimates the concentration of deposition value for each source and receptor combination for each hour of input, and calculates user-selected short-term averages. The user also has the option of selecting averages for the entire period of input meteorology. 5.1.6 ISC3 PARAMETER LIMITS ISCST35 has a set limit of one thousand (1,000) sources, five hundred (500) source groups, twelve (12) pollutants, ten thousand (10,000) recepters. five (5) gridded receptor networks, and seven (7) short-term averages (ISCST3). 5.1.7 REGULATORY APPLICABILITY The U.S. Environmental Protection Agency (EPA) maintains the Guideline on Air Quality Models (Revised)" (hereafter referred to as the "Guideline") which provides the agency's guidance on regulatory applicability of air quality dispersion models in the review and preparation of new source permits and State Implementation Plan (SIP) revisions. When using the ISCST3 model the regulatory default option as described below was used. This ensures compliance with most of the Council for Nuclear Safety's requirements on dispersion modelling. 5 U S Environmental Protection Agency (September 1995), User's guide for the Industrial Source Complex (ISC3) Dispersion Models, Volume I - User Instructions. Office for Air Quality Planning and Standards, Emissions, Monitoring, and Analysis Division (EPA), North Carolina. 6 Environmental Protection Agency (1987b), Guideline on air quality models (Revised) and Supplement A, EPA- 450/2-78-027R, U S Environmental Protection Agency, Carolina, USA 5-6 5.1.8 REGULATORY DEFAULT OPTION The regulatory default option is controlled from the MODELOPT keyword on the CO pathway. As its name implies, this keyword controls the selection of modelling options. It is a mandatory, non-repeatable keyword, and it is an especially important keyword for understanding and controlling the operation of the ISC models. The regulatory default options, as specified in the Guideline on Air Quality Models, are truly the default options for the ISC models. That is to say that, unless specified otherwise through the available keyword options, the ISC models implement the following regulatory options: " Use stack-tip downwash (except for Schulman-Scire downwash); • Use buoyancy-induced dispersion (except for Schulman-Scire downwash); • Do not use gradual plume rise (except for building downwash); II Use the calms processing routines; • Use upper-bound concentration estimates for sources influenced by building downwash from super-squat buildings; II Use default wind profile exponents; and • Use default vertical potential temperature gradients. 5.1.9 METEOROLOGICAL DATA Five-minute weather data for a full year (1997) was manipulated to calculate the variation in wind speed and direction and an hourly average was then used. The 1997 data for Welkom was obtained from the National Weather Bureau'. The standard deviation cD2 of the wind direction was calculated for hourly averaged data according to the method of Campbell Scientific". The stability classes were calculated using the method of Turner9. 7 Five minute weather data for 1997 supplied electronically by the South African Weather Bureau 8 Cambell Scientific, Inc. (1995) CR10X Measurement and control system, Operators Manual. 9 Turner B 0 (1970). Workbook of Atmospheric Dispersion Estimate. 5-7 The Weather Bureau could not provide mixing height data as they only fly meteorological weather balloons at midday. To overcome this problem a set of mixing height data obtained from Mr J Slabbert of PSI Consultants was used to determine conservative mixing heights not area bound to be used for the dispersion modelling. For winter days and winter nights mixing heights of 200 and 60 metres were used. For summer days and nights mixing heights of 1000 and 100 metres were used. This assumption may be shown to be conservative as the following simulation of a single tailings dam using the true mixing heights and the conservative mixing heights shows: 1100&--~------~--------~--~----------__' Sensltlylty Analysis' Mixing Radon eoneentratten for menured m1.lng heights (J Slobbert) Radon concentr.tlons for con •• rvatlve mixing heights Summer days - 1000 metre Summ er nights - 100 metre Winter days - 200 metre Winter nights - 50 metre Soure 1000)( 1000 m Release height 25 metre Emanatlon rat. ; 1 Bqlm 2/see Met File: Actual KOSH Metre Figure 5.1: Simulation of different Mixing Heights. 5-8 5.1.10VALlDATION OF THE ISCST3 MODEL. The Chamber of Mines commissioned Industry and Environment Consultants CC to model and to validate the ISCST3 model against the Impact mode!'? A number of tailings dams at Anglogold's Vaal River Operations" were modelled using ISCST3. This report has been submitted to the Council for Nuclear Safety under separate cover Anglogold, Vaal River Operations. The weather and geographical information was then submitted to the consultants who then modelled the same slimes dams using Impact. The following table compares the calculated radon concentrations in a line across the site and in the predominant wind direction. The correlation is acceptable considering the large number of variables. Distance Impact (Bq m') 2.2km 2.8 1.4 4.0km 1.8 1.2 6.0km 1.2 1.1 10km 0.8 0.8 Table 5-1: Comparison of radon concentrations calculated using ISCST3 and Impact models. 10 Beak Consultants Limited (1996), Integrated Model for the Probabilistic Assessment of Contaminant Transport (IMPACT), Arrow Road, Ontario, Canada. 1 Similar gold mining operations in the Klerksdorp area, located in the North-West Province 5-9 5.1.11 MODELLING RESULTS AND DOSE CONVERSION The weather data is available on site in electronic format. The ISCST3 input and output files used for the calculations are attached as APPENDIX 1. The calculated radon concentrations were interpolated using the Surfer Grid Based Contouring programme 12 and a Kriging algorithm 13 (geostatistical interpolation method that produces contour and surface plots from irregularly spaced data). The radon concentrations were converted using a dose conversion factor of 14.6 Bq m-3 radon gas per 250 ~lSV effective dose per annum as per the Basic Safety Series, IAEA Safety Series NO.116, Page 9914. The final potential radon dose contours in ~lSv/a are indicated in Figure 5-2. The area sources (tailings dams and waste rock dumps) are indicated by yellow squares and the point sources (upcast shafts) are indicated by red dots. The whole surface area considered is indicated on a grid of about 32 000 metres by 40 000 metres, with north being in the positive y direction. The maximum potential radon gas contribution to the potential dose from the sources considered, is 106 uSv/a: 1ST HIGHEST VALUE IS 6.19 Bq m-3 AT (13000,4500) 2ND HIGHEST VALUE IS 6.17 Bq m-3 AT (16000,4500) 12 SurfefrorWindowsV,ersion6 13 CressieNAC,(1990T) heoriginsofKrigingM. athematicGael ologVyol22p239-252 14 IAEAI,nternationbaal sicsafetystandardfsorprotectioangainsitonisingradiationandthesafetyofradiation sourcesV,iennaI,AEASafetySeriesNo116,Page99. 5-10 Although the highest potential radon concentrations are predicted on top of the tailings dams, this is as a result of interpolation and is not calculated values, the reason being that the integral in Equation 5-2 is not mathematically defined inside a source. 5-11 -5000 o 5000 10000 15000 20000 25000 30000 Figure 5-2: Potential radon dose contours for the Welkom area (J..lSv/a) 5-12 5.2 WATER DOSE MODELLING The potential exposure to radioactively contaminated water sources was modelled using a simple Microsoft Excel spreadsheet for calculating transfers of activity from the water source via the different pathways e.g. soil, plants, animals etc., to final consumption by humans. The structure of the model is indicated in APPENDIX 2. The activity concentration values and isotope ratios in the appendix are typical of that in the water sources around the mines". This is summarised in Table 5-2: Table 5-2: Typical concentrations in water Uranium-238 Series U-238 0.06 Th-234 0.06 Pa-234 0.06 U-234 0.06 Th-230 0.06 Ra-226 0.02 Pb-214 0.02 Bi-214 0.02 Pb-210 0.02 Bi-210 0.02 Po-210 0.008 The transfer factors and dose conversion factors were based on ICRP 7i6, Licensing Guide LG-103i7, as well as IAEA Basic Safety Standards". Only the 238U-serieswas considered, as it is the predominant decay series. 15 Analysis by the Atomic Energy Corporation 16 Annals of the ICRP, Publication 72 (September 1995), Age dependent doses to members of the public from intake of radionuclides: Part5 Compilation of ingestion and inhalation dose coefficients, International Commission on Radiological Protection 17 Licencing guide LG-1 032 Revision 0 (April 1997), Guideline on the assessment of radiation hazards to members of the public from mining and minerals processing facilities, Council for Nuclear Safety. 18 IAEA, International basic safety standards for protection against ionising radiation and the safety of radiation sources, Vienna, IAEA Safety Series No 115 5-13 The mines are establishing extensive water management systems to monitor mainly non-radioactive pollutants from the mining processes. These parameters such as acidity, salt loading and chemical toxins 19 are the predominant environmental hazards and it is a safe assumption that controlling water systems according to these parameters, would also be adequate in terms of uranium and its associated decay products. Radioactivity levels must however still be considered in these monitoring and management systems". Seeing that drinking water is mainly supplied to the area from sources that are not located in the mining area". the immediate exposure potential is negligible. The one scenario, that of secondary exposure such as consuming crops and animals living on potentially contaminated water, is also fairly insignificant if one considers the effective transfer of 238U series (Table 5-3). Table 5-3: Typical exposure scenario for consumption of contaminated water Dose to the Public Adult 15 year 10 year 5 year 1 year uSv/a I..lSv/a I..lSv/a I..lSv/a I..lSv/a FOODSTUFF Meat 3.11 4.43 3.36 2.82 1.69 Poultry 0.35 0.42 0.36 0.26 0.16 Eggs 0.12 0.14 0.13 0.10 0.05 Fish Products 0.66 0.51 0.62 0.45 0.17 Grain Products 0.00 0.00 0.00 0.00 0.00 Roots & Fruits 0.00 0.00 0.00 0.00 0.00 Leafy 0.00 0.00 0.00 0.00 0.00 Vegetables LIQUIDS Milk Products 0.96 2.34 2.45 3.40 6.25 Water & 35.69 63.96 35.73 37.71 54.69 Beverages EFFECTIVE ANNUAL 40.88 71.81 42.65 44.73 63.01 DOSE I.ISv/a 19 Water Management Plan Volume 8 (1997), Free State Goldfields and Lower Vet River catchment, Department of Water Affairs and Forestry 2-3 20 Environmental Management Programme Report (1997) Version 4, Free State Consolidated Gold Mines ~Operations) Limited 1 Vaal River system 5-14 The major potential exposure pathways in this regard is the drinking water scenario, and to a much lesser extent the consumption of meat (Table 5-4). From the last table the following ratios are determined: Table 5-4: Relative contribution (%) of different pathways to the total potential dose (100%) from water sources. Meat 7.61 6.17 7.88 6.30 2.68 Poultry 0.86 0.58 0.84 0.58 0.25 Eggs 0.29 0.19 0.30 0.22 0.08 Fish Products 1.61 0.71 1.45 1.01 0.27 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2.35 3.26 5.74 7.60 9.92 From the last table it is clear that the tolerable activity concentrations in water can be much higher if water is not used for drinking purposes, which contributes for more than 80% of the potential water dose. This is significant in terms of the typical agricultural activities around the mines. Process water dams are not considered as a direct source term as the quality of the water is generally so bad in terms of acidity and taste, that it is not regarded as a potable source'". The long term water quality and management is one of the aspects that must still be addressed by most of the mines and will form part of an overall monitoring and modelling programme that falls outside the scope of this assessment. 22 Environmental Management Programme Report (1997) Version 4, Free State Consolidated Gold Mines (Operations) Limited 5-15 Previous studies23 on the movement of Uranium and its decay series in soils and water systems around the mining areas show that no significant enhancement of radium concentrations could be detected in and around the Witwatersrand mining area. In spite of the vast quantities of total radium contained in the tailings darns", its relatively low concentration together with the verification of its extremely low mobilrty" indicate that its spread in the environment, at least in the short to medium term, is unlikely to reach concerning proportions. In addition, the Department of Water Affairs and Forestry (DWAF) performed extensive water analysis during 1996 (Kernpsterj". The radioactivity concentrations in the Sand River were well below the target water quality values set by DWAF. The only area of concern was indicated as being the Mahem Spruit that has subsequently being monitored extensively for all pollutants. This area is also one of the focus areas of the Anglogold Hydrological Contamination Master Plan (HCMP) for the whole lease area. The water analyses results for the Welkom, Harmony, Virginia and Odendaalsrus areas summarised in the following tables: 23 De Jesus et al (1987) An assessment of the radium-226 concentration levels in tailings dams and environmental waters in the gold / uranium mining areas of the Witwatersrand, Atomic Energy Corporation of South Africa, 11-14 24 Slimes dam survey results (1996), Nuclear Licence NL-57, Appendix III 25 Rahn P H (1978) Seepage from uranium tailing ponds and its impact on ground water m Albuquerque, New Mexico 26 Kempster PLet al (1996) Overview of radioactivity in water sources: Uranium, Radium and Thorium. Appendix 1 Table 6. 5-16 Table 5-5: 226Ra Water Analysis Results (Bq rn') around Harmony and Virginia (1995 )27 *N/S - not sampled 27 Harmony Gold Mine Water Analysis Results 5-17 Table 5-6: Water analyses results in and around the Welkom area28 49 Doringpan 24/07/96 62 50 Doringpan 18/03/97 <25 51 Doringpan 08/10/96 40 52 Doringpan 08/10/96 58 53 Doringpan 23/02/96 39 54 Doringpan 08/10/96 <30 55 Doringpan 12/12/97 78 56 Doringpan 08/10/96 58 57 Doringpan 08/10/96 62 58 Doringpan 17/09/97 66 111 Hester's Pan - Municipality side 17/09/97 25 112 Hester's Pan - Municipality side 09/01/97 115 113 Hester's Pan - Municipality side 12/12/97 82 114 Hester's Pan - Municipality side 18/03/97 97 121 Mahem spruit 8/9/98 682 122 Mahem spruit 1/98 143 123 Mahem spruit 17/09/97 120 127 Mostert Canal 1/98 23 128 Mostert Canal 17/09/97 25 129 Mostert Canal 8/9/98 <25 130 Mostert Canal 04/10/95 <30 131 Mostert Canal 18/03/97 <25 144 V-Notch Sandriver 18/03/97 49 145 V-Notch Sandriver 21/06/96 <25 146 V-Notch Sandriver 08/10/96 <30 147 v-Noten Sandriver 1/98 152 148 V-Notch Sandriver 09/01/97 <25 149 V-Notch Sandriver 24/07/96 <25 150 Welkom to Bultfontein road "Mahem spruit culvert" 24/07/96 <25 157 Witpan 09/01/97 <25 158 Witpan 18/03/97 <25 159 Witpan 8/9/98 <25 160 Witpan 1/98 52 28 Nuclear Licence NL-57 Effluent Reports 5-18 Table 5-7: Water analyses results in and around the Odendaalsrus and Allanridge areas29 (July and October 1997, respectively) Borehole DC-316 Swartpan 10 <25 15 <25 Farm Graspan - Taljaard 6 <25 10 <25 Farm Graspan - Haasbroek 23 <25 <3.25 <25 Farm Klein Bloemfontein 10 <25 10 <25 Farm Rosedale - Du Randt <3.25 <25 11 <25 Farm Spes Bona - Naude 17 <25 4 292 Borehole DC-316 Swartpan 119 <25 <3.25 <25 Farm Graspan - Taljaard 6 <25 22 <25 Farm Graspan - Haasbroek 23 <25 <3.25 <25 Farm Klein Bloemfontein <3.25 <25 15 <25 Farm Rosedale - Du Randt 24 <25 17 <25 Farm Spes Bona - Naude 20 <25 <3.25 <25 The only major potential contribution to the public dose is that of drinking water from the limited intake from the Sand River. From table 5-5 it seems that no significant increase in the radioactivity concentrations occurs between the upstream and downstream sampling locations. The potential doses calculated for the Free State area in the industry study" is also in the order of 20-70 I-lSv/a. As stated earlier in the report, the lack of appropriate background radioactivity concentrations in natural water sources makes it very difficult to determine incremental contributions from the mines. This is one of the important aspects that will have to be addressed in future monitoring and modelling programmes. 29 Loraine Gold Mines: Report LGMLREP001 RevO 30 Jansen van Vuuren et al (1995), Assessment of the Radiological Impact to the public from surface works on mines: Exposures from aquatic sources, Final Report GU9301, CSIR. 5-19 5.3 DUST MODELLING Inhalation From a previous industry study" conducted on a few typical gold mines in South Africa, one of which is in the Free State Goldfields, the contribution to the potential public dose by inhalation of radioactive dust from the slimes dams and waste rock dumps is very small. This, and the fact that the current thinking is to grass all tailings dams in the future32, thus drastically reducing the potential for windblown dust, makes any elaborate study of this exposure pathway unjustifiable. It was decided to use the extensive dust measurements results obtained over a few years at Ergo located near Brakpan. The industry study quotes a potential dose from dust sources as being not higher than 50 ~lSv/a. Radiation hazard assessments conducted on tailings dam workers" wearing personal air samplers indicated potential dust exposures less than the detection limits of the instrumentation". In addition, an interesting observation is that the respirable fraction of the dust was very small compared to the total volume of dust collected. The dust from tailings dams could thus pose more of a nuisance value than a radiation exposure risk. The methods to determine the dust source terms are fraught with difficulties. The principle of the method is sound but the actual measurement component degrades the result considerably" Equipment is also frequently stolen from the veld. 31 Jansen van Vuuren et al (1995), Assessment of the Radiological Impact to the public from surface works on mines: Exposures from aquatic sources, Final Report GU9301, CSIR. Chapter 2.2 32 Environmental Management Programme Report (1997) Version 4, Free State Consolidated Gold Mines ~Operations) Limited 3 Slimes dam survey results (1996), Nuclear Licence NL-57 34 ML Instrumentation, ML-114B spectrometer, LLD = 0.0052 Bq.m" 35 GU9301 ;Assessment of radiological impact from to the public from surface works on mines; Radon and dust exposure pathways, Strydom et al. 5-20 For this reason and the high cost of measuring the airborne dust concentrations, it was decided to use the extensive dust measurements results obtained over a few years at Ergo located near Brakpan". To calculate the contribution of the dust to the public dose, the results of the dust model of Anglogold's ERGO operations by Environmental management Services CC (Dr. Lucien Burger) in Report No. ERGO/95/a was used. The USA Environmental Agency's Industrial Source Complex ISCST2 and Fugitive Dust FOM models were used. The highest dust concentration calculated at the 16 km square Withok dam is 400 ~lg m-3. The average concentration of uranium in slimes dam dust at the Free State mines is 2.35 Bq/g for Uranium and about 1 Bq/g for Radium. If the assumption is made that the material contains only Uranium in secular equilibrium with its progeny and that the concentration is 2.35 Bq/g, the dose due to a dust concentration of O,4mg/m3 may be calculated. According to the IAEA Basic Safety Standards. the annual limit of intake of uranium ore dust is 3000Bq/a for workers working 2000hrs per year. For a member of the public the time is 8760hrs. The dust concentration of 0,4 mg m-3 will give a dose of about 70~Sv/a to a member of the public. In a study of inhalation dust at the Stilfontein Mine37 the highest average, worst case dose due to airborne radioactive dust is 161 uSv/a. The industry study GU 930154 done for Hartebeesfontein with the dust actually measured, indicated a dose due to inhalation of 47 uSv/a. Similar to the Free State, dust sampling was performed on slimes dam workers in the Klerksdorp area as part of the hazard assessment for slimes dam workers:". 36 Report AER97.039 Q erg, Annergan Environmental Research (PTV) LTD 37 Assessment of public radiological exposure via the air pathway from sources and releases at Stilfontein Gold Mining Co, R Strydom, September 1998 38 MNMVR/REP008 Vaal Reefs Slimes Dams Hazard Assessment Report 5-21 These measurements over a period of two months showed no radiation dose to workers due to the inhalation of dust. Similar results were also obtained for all the mines in area. This indicates that the dust concentration derived from the theoretical model done for Ergo is extremely conservative. Further, comparing the theoretical values of the dust deposited to the actual dust deposited shows that the models used over predicts the dust fallout 17 times. It may therefor be concluded that the dose due to inhaled dust is exaggerated. 5-22 Ingestion If it is difficult to measure the inhalation of radioactive dust then it is even more difficult to measure the amount of dust ingested by the public. This study did not attempt to quantify the ingestion of dust. The study done by Bain et al39 analysed vegetables grown on the Marievale Farm in the Brakpan area, and the Vlakfontein and Luipaardsvlei Farms in the Randfontein Area. The study attempted to quantify the effect of radioactively contaminated water on the uptake of radioactivity in the plants. As the plants were harvested from the farms the effect of radioactive dust on the plants cannot be excluded and the doses calculated by the authors in the study must therefor be seen to be due to the water used for irrigation and dust settling on the plants. Furthermore the plants are grown in soil which is covered by mine dust which is ploughed into the soil every time the soil is tilled. Table 5-8: Annual Effective Dose and committed Effective dose from various ingestion pathways (Bain et al) in ~lSV. *The oats was cultivated on a slimes dam and is therefor not applicable to the argument. The results show that the highest dose due to the ingestion of vegetables is 2~Sv. 39 Bain et ai, Investigations into the concentration ratios of selected Radionuclides in aquatic ecosystems affected by mine drainage effluents with reference to the Study of Potential Pathways to Man, WRC Report No. 313/1/94 5-23 CHAPTER 6 ENVIRONMENTAL MEASUREMENTS AND ANALYSES 6.1 ENVIRONMENTAL RADON MEASUREMENTS 6-2 6.2 WATER ANALYSES RESULTS 6-12 6-3 EXTERNAL RADIATION 6-15 6-1 6 ENVIRONMENTAL MEASUREMENTS 6.1 ENVIRONMENTAL RADON MEASUREMENTS Environmental radon gas measurements were taken in and around the Free State Goldfields area to identify excessively high radon concentrations (> 200 Bq m-3)1 and to establish some correlation with the predicted results of the modelling exercise. The following techniques were used to measure radon concentration in the outdoor air, as well as limited measurements indoors: • Alpha track etch devices, in this case RGM's2, were exposed for a period of approximately 2 to 3 months during 1996 as part of an assessment of radiation doses to tailings dam workers". The workers on the tailings dams wore some of the RGM's and a few were placed in buildings on the site. These results are listed in Table 6-1. • Radon gas concentrations were also measured around the Welkom area over 24-hour periods using an Alphaguard Radon Gas Monitor" that measures the radon gas concentration continuously and records the values at ten-minute intervals. These results are listed in Table 6-2. • A number of E-PERM Electret gas monitors were placed outdoors in the areas surrounding the mines, as well as a few non-mining areas. These are listed in Table 6-3 and 6-4. The measurements taken in the areas well outside the gold mining area serves as criteria for "background" radon concentrations. The results of these environmental radon gas measurements are summarised in the following tables and diagrams. 1 AnnalsoftheICRPP, ublicatio6n5(Septembe1r993)P, rotectioangainsRt adon-22a2tHomeandatWork, InternationCaol mmissioonnRadiologicParlotection 2 StrydomR,PARCScientific 3 Slimesdamsurveyresults(1996)N, ucleaLricenceNL-57 4 AlphaGUARPDrofessionRaladonMonito(r1997)O, peratinMganuaGl. enitroInnstrumentFsr,ankfurGt,ermany 6-2 Table 6-1: RGM results of tailings dam workers and on-site dwellings 40 57 36 Average 1 6-3 Table 6-2: AlphaGUARD results on environmental measurements Homes (indoors) Welkom 1 35.6 10.7 Welkom 2 33.4 6.5 Welkom 3 29.8 7.9 6-4 Environment (outdoors) Welkom 1 22.6 13.5 Welkom 2 20.6 6.0 Welkom 3 24.1 7.2 Roodepoort 1 24.8 7.0 Roodepoort 2 25.6 12.5 Bethlehem 28.7 9.8 *(Exposure period of at least 24 hours) No excessively high radon gas concentrations were detected in the buildings on the mines or even on top of the tailings dams. This corresponds well with the predictions of the dispersion modelling. The day night variation in the environmental radon gas concentration as a result of the temperature and inversion layer changes can be clearly seen in Figures 6-1, 6-2 and 6-3. The highest radon concentrations were measured early in the morning. This corresponds well with studies elsewhere in the world such as Gessel (1983)5. 5 Gessel T F (1983) Background atmospheric 222Rn concentrations outdoors and indoors: A Review, Health Physics, Vol. 45 No 2 (289-302) 6-5 t-I:..lli-.·. - I I _.-'.:ol. ..... L"· ~·'I~.r-". 'r~"''' Radon in Welkom T • I I ~""I I .. - lo. r 1"', .... I'"I , ... ~ .. I.. ~ "ir'.~lIif"~I ..L ......-.I,...,.u '- 9-:["-'11 ",.Jo \ - 1 •. . ..j_. r • I .. I "",1 ', I ,. 90 - J. ï> Jl Jl . I,.I I I I.. I II. 60 '? E; cr al 30 ~,. II . ,.I I' ,. ... 1 0 .: ,... i,l_ \ ~ ... n. , 144 287 .... II, I ~ 'I" Time (approx 3 days) I r Figure 6-1: Daily variation in radon concentration in the Welkom area Radon vs Temperature .1...1 I .. 'I ,-_ I •• 50 \ I' , , 40 - , .. , I • 30 20 10 0+-~~~~~~--~~~~~~~~~~-7~---.-,~1 • --------------~137 Time (24 hours) .. _ Radon (Bq/m3) _ Temperature (CeIs) . . Linear (Radon (Bq/m3)) _.. _... Linear (Temperature (CeIs)) "" _L ~ Figure 6-2: Radon concentration as a function of temperature 6-6 Radon vs other environmental parameters J ; f· ; ~ - :. Ir' I -- .-- '-; -I _I .,- I' II. II. ',.J - 80 60 40 20 - .... T _~JI J ... - :.. II 137-' ( I I - Time (24 hours) , : ,r. __ Radon (Bq/m3) -- Temperature (CeIs) -- Rel. Air A"essure -- t-+.Jmidity (%) Figure 6-3: Radon gas concentrations as a function of other environmental parameters Radon gas measurements were also taken in areas outside the Free State Goldfields to establish some kind of a reference background. This can be seen in Figure 6-4: 'I " 188 Time (approx 31 hours) Figure 6-4: Radon concentrations in towns outside the Free State Goldfields (See Table 6-2 for detail) 6-7 From the outdoor and indoor radon concentrations measured in this assessment, it is clear that the radon concentrations in and around the Free State Goldfields are not significantly higher than in any other non-mining area. In addition, according to the RGM and Alphaguard surveys inside houses the average indoor radon concentration is in the order of 30 Bq m-3 to 45 Bq rn', compared to a South African national average of 50 Bq m-3 as determined by Leuschner (1991 )6. The Alphaguard measurements estimated an average outdoor radon gas concentration for the Goldfields in the order of 20 Bq m-3 to 25 Bq m-3, compared to a similar range of concentrations for towns outside the gold mining area. 6 Leuschner et al (Nov 1991). National seasonally averaged radon concentrations, Atomic Energy Corporation & Department of Health AEC, Pretoria 6-8 As part of the assessment RGM's were deployed around a single tailings dam to determine the correlation between the dispersion modelling results and environmental radon concentrations. However, as is evident from Table 6-3, the potential contribution from the tailings dam fails to be statistically significant considering the natural radon background levels. The contribution from the tailings dam is in the order of 1-4 Bq m-3 and disappears in the natural radon background of 25-35 Bq m-3. As the daily variation in outdoor radon concentrations is already in the order of tens of Bq m-3 only very long term integrated radon measurements may indicate some statistically meaningful inter-comparison with the modelling exercise. It is however safe to say that the order of magnitude of the radon contributions from the mines are correct in that no significantly high radon levels were observed in the area. Table 6-3: E-PERM Electret monitor (LST) results for the Goldfields area Coghlan St 49.8 0.1 31.5 Cordelia St 49.8 0.1 54.6 Bronville 49.8 0.1 27.5 Hospital 50.1 0.1 33.9 Campbell St 50.7 0.1 40.1 Toronto St 50.7 0.1 33.0 Agulhas St 50.7 0.1 57.9 FG Club 50.1 0.1 16.0 Odendaalsrus 49.8 0.1 57.8 Holdings G/Plant 51.0 0.1 64.8 Stores 50.8 0.1 32.5 GolfClub 49.9 0.1 45.6 Virginia 50.7 0.1 64.4 50.7 0.1 52.7 Tsepong 49.1 0.1 43.6 49.1 0.1 24.9 Hospital Odendaalsrus 50.1 0.1 50.5 50.1 0.1 64.1 Thabong 50.7 0.1 59.4 FEMTS 49.9 0.1 37.5 49.9 0.1 39.4 6-9 Dagbreek North 49.9 0.1 64.8 49.9 0.1 50.8 Pump Station Witpan 50.1 0.1 56.3 Pump Station D Dam. 50.1 0.1 50.8 50.1 0.1 37.9 Bronville 49.8 0.1 66.6 49.8 0.1 62.3 50.1 0.1 66.2 S. G Tappin & Son 50.1 0.1 39.6 50.1 0.1 26.0 49.1 0.1 40.9 Hospital 50.1 0.1 56.6 50.1 0.1 50.2 Mine Mess 50.1 0.1 23.9 50.1 0.1 25.8 Airport 50.1 0.1 34.2 50.1 0.1 46.7 Doring Pan Game Farm 50.1 0.1 40.5 50.1 0.1 33.6 Poultry Farms 50.1 0.1 36.7 50.1 0.1 44.5 Average 44.9 Standard Dev. 13.7 Table 6-4: E-PERM Electret monitor (LST) results for non-mining areas 58.8 47.8 0.1 69.2 Bultfontein 58.4 0.1 29.5 58.4 0.1 41.1 Avera e 55.2 6-10 -.- - -. - ..--.-.' • I• r_... RADON IN HOMES .. .... .,....,. 12 r- - 10 ~ 8 c r- ~ 6 .. i- - i- ItT Ie 4 - - - - - l- . -IL. I 2 J' - - - .---< ~ o n <:) ,,_,<:) ~ n;,<:)- I~-..,. - ,', Radon (Bq,m-3) Figure 6-5: Frequency distribution of radon concentrations (Table 6-3) The E-PERM measurements were consistently higher than the Alphaguard measurements and did not seem to be consistent where duplicate sets of monitors were deployed. This is attributed to the large influence that external radiation has on the Electret ion chambers" In Table 6-3 and Table 6-4 a generic correction for the gamma background was used and this is one of the possible explanations for the inconsistency. However, the order of magnitude of the radon concentrations in the Free State Goldfields seem to be the same as that measured in towns outside the gold mining area. 7 Cole C M (June 1996) Appropriate methods for implementing ambient background subtraction regarding radon monitoring results obtained with Electret ion chamber (EIC's) in field monitoring applications, Project Team Meeting, Council for Nuclear Safety Information Bulletin No 7 6-11 6.2 WATER ANALYSES The process water dams on site are not considered as sources of drinking water due to the taste and quality (pH & salt concentration) of the water and the fact that drinking water is supplied from a source outside the mining area. The process water dams could however have a long-term impact on ground water systems and will be considered as part of the overall water management programme of the mines. Groundwater management and monitoring systems are being established" and radioactivity will be one of the potential pollutants considered in the overall water management programmes of the mines in the Free State. This is a long-term project and adequate data must first be collected from the bore hole monitoring before any final judgement can be made on the longer term impacts of radioactivity from the mines on the underground water systems. From the previous studies (de Jesus et al)9 and monitoring results in other areas (Vaal River Operations)'? it would seem that no significant quantities of the 238U series finds their way to the groundwater systems. 8 EnvironmentMalanagemenPtrogrammReepor(t1997)Version4, FreeStateConsolidateGdoldMines ~OperationLsi)mited DeJesusASMetal(1987)A, nassessmenotftheRadium-22c6oncentratiolenvelsintailingsdamsand environmentwaal tersinthegoldanduraniumminingareasoftheWitwatersranAd,tomicEnergyCorporation 10AnglogolVdaalRiverOperationgsroundwatearnalysisresults 6-12 In addition to water analysis, fresh fish caught in one of the pans in the area were analysed for radioactivity. The specific pan received large volumes of water discharged from one of the shafts in the area and was considered to be a potential worst case in terms of potential contamination. The public uses the pan for recreational purposes and fishing in the area is fairly common. Table 6-5: Radio-analysis 11of fish samples from pan Carp Edible parts 2.37 <0.012 3.33 Intestines 7.4 0.206 2.95 Bones 5.85 0.032 4.39 Barbel Edible parts 0.64 <0.009 <0.6 Intestines 16.1 0.119 4.67 Bones 12.8 <0.049 3.50 Assuming equilibrium with the other nuclides in the 238Useries, an annual consumption of 25 kg of fish12 equates to an effective radiation dose of 200 IlSv/a for an adult living solely of the barbel in the pan. This is a very conservative calculation as equilibrium is assumed between 238Uand 226Ra and their decay products, as well as the fact that no background correction was made for natural radioactivity levels in fish. More detailed analysis is required to determine the equilibrium ratios of all the nuclides as well as analysis of fish originating from areas outside the Goldfields for background corrections. A possible concern in terms of surface water sources is that of informal settlements around the process water dams which contain fairly high concentrations of uranium and radium, up to a few hundred Bq m-3. If for 11 Atomic Energy Corporation of South Africa, Report No RA 1171-1 6-13 example a human should consume its full quota of water and related foodstuff from a process dam with 238Uand 226Raconcentrations of 2000 Bq m-3 and 700 Bq m-3respectively, the potential radiation exposure would be in the order of 3 to 4 mSv/a. There will have to be close co-operation between local authorities and the mines to prevent access to and use of these potentially contaminated water sources for drinking water. Education of the public on the potential health hazards associated with mining activities in general is of utmost importance. 12 IAEA, International basic safety standards for protection against ionising radiation and the safety of radiation sources, Vienna, IAEA Safety Series No 115 6-14 6-3 EXTERNAL RADIATION SABS TLD badges 13 were issued to workers on the tailings dams for a period of two months. None of the workers registered a gamma dose that corresponds to a dose equivalent of more than 0.15 mSv for the wearing period. In addition, when the closest distance of any member of the public from a tailings dam or waste rock dump is considered, this exposure pathway becomes insignificant in terms of the inverse square relationship between gamma dose rate and distance. Locations of the TLD's are listed in Table 6-6. Table 6-6: TLD's issued to tailings dam workers and stationary locations all yielded zero results (i.e. less than 0.15 mSv) 13 South African Bureau of Standards. 6-15 Similarly to public access control to potentially contaminated water sources, some form of institutional controls will have to be set up to prevent the building of houses or informal settlements on tailings dams. Although the gamma dose rate diminishes with distance from the tailings dams, living directly on top of a tailings dam could cause significant gamma radiation exposures when measured against public dose limits. 6-16 CHAPTER 7 CONCLUSIONS 7 -1 7 CONCLUSIONS It is clear from the radon flux measurements that the result of a flux measurement depends on the type of measurement conducted. All the techniques employed during the assessment proved to be sensitive in terms of disturbing the medium from which the radon flux is measured or the influence it has on the radon flux from the medium itself. However, the range of radon fluxes between 0.05 Bq m-2 S-1 and 0.2 Bq m-2 S-1 gives a good indication of the true radon flux from the tailings dams. The value of 1 Bq m-2 S-1 used in the modelling exercise may well prove to be conservative once more work is done in this regard. The environmental radon levels measured indoors and outdoors seem to confirm that the natural radon levels in the Free State Goldfields do not differ much from other non-mining areas. No excessively high indoor radon concentrations (>200Bq rn') could be detected and no intervention is required at this stage. Radon from the tailings dams, waste rock dumps and upeast shafts is considered to be main contributor to the potential radiation exposures to the public. The maximum potential radon contribution from all these sources was in the order of 6 Bq m-3, or an equivalent dose of 106 IlSvIa. This was calculated for a conservative radon flux of 1 Bq m-2 S-1. Dust from tailings dams is not considered to be a long term radiation exposure problem as most of the mines' Environmental Management Programmes (EMPR's) indicate that the tailings dams will all be rehabilitated and grassed within the next 30 odd years. From limited studies conducted around gold mines in South Africa, dust seems to have more of a nuisance value than a radiation exposure risk. 7-2 External gamma radiation from the tailings dams and waste rock dumps has a negligible contribution to the public dose, especially when compared to natural background levels and also considering the distance of potentially exposed members of the public from the waste rock dumps and tailings dams. Some institutional controls will however have to be established to prevent uncontrolled housing settlement on top of tailings dams. Potential radiation exposure due to consumption and use of contaminated surface process water sources on the mines might have an impact on the public if access to process water dams are not properly controlled. If for example a human should consume its full quota of water and related foodstuff from some of the worst contaminated process dams, the potential radiation exposure would be in the order of a few mSv/a. Drinking water, which constitutes about 80% of the potential exposure to water sources, is provided mainly from sources outside the Free State Goldfields and is not considered as an immediate problem area. The water quality and taste of the process water dams are generally very poor and even inadvertent use of these sources for drinking water is highly unlikely. One potential radiological impact from surface water sources as well as tailings dams and waste rock dumps is possible seepage and contamination into groundwater systems. Much more detailed monitoring and modelling exercises are required determine the long-term impact on the groundwater systems. From the impermeable geology of the area and the slow migration properties of 238U and its decay products in groundwater systems, it is not expected that groundwater systems will be adversely affected by radioactivity from the mines. However, radioactivity must be addressed as another pollutant in the current water management programmes being established by the mines. 7-3 Groundwater monitoring programmes are extremely costly and usually take several years to provide adequate data for modelling of water movement and possible contamination plumes. Predictions on long-term groundwater impacts can only be made once these detailed results are available. One of the difficulties during the assessment was the lack of information on natural background radiation levels, especially in terms of water, dust (soil) and associated products. It is relatively easy to determine the characteristics of radiation sources for modelling exercises, but the model results must be verified with environmental measurements. In other words it is essential to determine the incremental contributions from the mining activities to background radiation levels. More data is thus required on what is considered as background radiation levels. The total potential radiation dose to the public from the mining activities is estimated as being in the order of 130 !lSv/a to 250 !lSv/a: Table 7-1: Potential radiation exposures to members of the public Radon gas 30 -110 Water sources and associated produce 50-70 Dust (Inhalation & Ingestion) 50-70 External radiation (off tailings dams) N/A 7-4 When compared to other day to day hazards the potential radiation dose from the mines seems fairly insignificant. Table 7-2 summarises some common causes of death in the UK1 as an example. Table 7-2: Average annual risk of death from some common causes Smoking 10 cigarettes a day 1 in 200 Natural causes (40 years old) 1 in 700 Road accidents 1 in 10000 Accidents at home 1 in 10000 Accidents at work 1 in 50000 Nuclear effluent exposure (300!lSv) 1 in 70000 *United Kingdom Data The gold mines in the Free State have been operational for the last fifty to hundred years. Only in the early 1990's did the Council for Nuclear Safety intervene in terms of radiological protection of the workers in mainly the acid and uranium plants and the underground areas where potential exposures of up to 20 mSv/a were experienced. The mines were issued with Nuclear Licences in terms of the Nuclear Energy Ace, which stipulated a public dose limit of 250 !lSv/a to members of the public. The situation in the early 1990's could have been regarded as one of intervention by the Council for Nuclear Safety, i.e. most of the tailings dams, waste rock dumps and upeast shafts were in operation or already redundant by the time the first licences were issued. This makes the interpretation and justification of the public dose limit in the nuclear licences very difficult. ICRP 60 (1990)3 regards the dose limit of 1 mSv/a only applicable to practices and not to intervention situations where the sources, pathways and exposed individuals are already in place when the decisions about control measures are considered. 1 National Radiological Protection Board (1989) Living with radiation, Fourth Edition p 24 2 Nuclear Energy Act, 1993 (Act No 131 of 1993) 3 Annals of the ICRP, Publication 60 Recommendations of the International Commission on Radiological Protection, International Commission on Radiological Protection 7-5 In most cases intervention cannot be applied at source. Intervention must always do more good than harm. This assessment considered most of the mines in the Free State Goldfields and the potential radiation exposures estimated in the assessment can be considered as the combined impact of nearly all of these facilities. It would seem that the more appropriate dose limit to be considered, is the 1000 IlSvIa quoted in ICRP 60 (1990). Measured against this limit the mines seem to be within, or at least in the order of what could be considered as an international public dose limit. Although not fully quantified in this assessment, the radiological benefits of possible intervention measures such as relocation or capping of tailings dams or waste rock dumps seems unlikely to exceed the detrimental effects it would have on the existing operations that provides financial security and infrastructure to a whole city of people. Add to this the scepticism and uncertainly of the assumed biological detriment of low level radiation and one could state that the potential exposures to the public from the mines in the Free State Goldfields are well within the principles of ALARA, i.e. doses are As Low as Reasonably Achievable, considering all social and economic factors. 7-6 APPENDIX 1 ISC3 MODELLING FILES (.LST) ISCST3 - (DATED 96113) IBM-PC VERSION (3.06) ISCST3R (C) COPYRIGHT 1992-1997, TRINITY CONSULTANTS, INC. Run Began on 12/10/1998 at 12:53:05 •• BREEZE AIR ISCST3 - C:IBREEZE\FSOIFSO.INP .. Trinity Consultants Incorporated, Dallas, TX CO STARTING CO TITLEONE ANGLOGOLD - FREE STATE OPERATIONS CO TITLElWO ENVIRONMENTAL RADON MODELLING CO MODELOPT CONC RURAL CO AVERTIME ANNUAL CO POLL UT ID RADON CO HALFLIFE 330394 CO TERRHGTS FLAT CO FLAGPOLE 1.5 CO RUNORNOT RUN CO FINISHED SO STARTING SO ELEVUNIT METERS SO LOCATION FSOS2A AREA 3000.0 20330.0 0 SO LOCATION FSOS2B AREA 3000.0 19060.0 0 SO LOCATION FSOS2C AREA 4330.0 20330.0 0 SO LOCATION FSOS2D AREA 4330.0 19060.0 0 SO LOCATION FSOS3 AREA 4240.0 17780.0 0 SO LOCATION FSOS4 AREA 6810.0 19780.0 0 SO LOCATION FSOS5A AREA 6300.0 15600.0 0 SO LOCATION FSOS5B AREA 6690.0 14630.0 0 SO LOCATION FSOS6 AREA 4300.0 13360.0 0 SO LOCATION FSOS8A AREA 16720.0 11420.0 0 SO LOCATION FSOS8B AREA 17060.0 10210.0 0 SO LOCATION FSOS8C AREA 17420.0 8930.0 0 SO LOCATION FSOS9 AREA 15480.0 7720.0 0 SO LOCATION FSOS10 AREA 12210.0 5150.0 0 SO LOCATION FSOS11 AREA 14750.0 5210.0 0 SO LOCATION FSOS12 AREA 16540.0 7060.0 0 SO LOCATION FSOS13 AREA 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SRCPARAM FSOWJ 1.000000E+00 30 960 210 66 0.00001 SO SRCPARAM FSOWK 1.000000E+00 30 570 300 7 0.00001 SO SRCPARAM FSOWL 1.000000E+00 30 420 600 29 0.00001 SO SRCPARAM FSOWM 1.000000E+00 30 510 270 25 0.00001 SO SRCPARAM FSOWN 1.000000E+00 30 330 420 90 0.00001 SO SRCPARAM FSOWO 1.000000E+00 30 540 390 26 0.00001 SO SRCPARAM FSOWR 1.000000E+00 30 660 360 8 0.00001 SO SRCPARAM FSOWS 1.000000E+00 30 360 390 70 0.00001 SO SRCPARAM FSOUB1 E 2.500000E+06 13.44 300 28.6 6 SOSRCPARAM FSOUB1W 1.100000E+06 13 300 10 6.7 SO SRCPARAM FSOUTSE 2.700000E+06 12.2 300 14.3 6.9 SO SRCPARAM FSOUMAN 1.900000E+06 15 300 15.3 7.2 SO SRCPARAM FSOUMAE 1.900000E+06 15 300 9.1 9.5 SO SRCPARAM FSOUMAS 1.700000E+06 10 300 14.3 7.1 SO SRCPARAM FSOUMAK 3.000000E+05 10 300 5.1 4.9 SO SRCPARAM ARMS7A 1.000000E+00 30 1230 1125 24 0.00001 SO SRCPARAM ARMS7B 1.000000E+00 30 1230 1125 24 0.00001 SO SRCPARAM ARMUAM1 3.000000E+05 7 300 3 6 SO SRCPARAM ARMUAM2 9.000000E+05 14 300 18.2 4.7 SO SRCPARAM ARMUAM3 4.000000E+05 12.5 300 4.2 6 SO SRCPARAM ARMUAM6 1.000000E+06 14 300 10.9 6.4 SO SRCPARAM ARMUAM7 8.000000E+05 14 300 8.6 6.4 SO SRCPARAM KADS1 1.000000E+00 30 1000 1290 90 0.00001 SO SRCPARAM KADWA 1.000000E+00 30 600 300 65 0.00001 SO SRCPARAM KADWB 1.000000E+00 30 180 240 85 0.00001 SO SRCPARAM KADWP 1.000000E+00 30 600 420 69 0.00001 SO SRCPARAM KADWO 1.000000E+00 30 450 600 28 0.00001 SO SRCPARAM KADWL3 1.000000E+00 30 450 540 0 0.00001 SO SRCPARAM KADUST1 8.000000E+05 13 300 6.1 7.4 SO SRCPARAM KADUST2 8.000000E+05 12 300 6.6 7.4 SO SRCPARAM KADUFR7 6.000000E+05 13 300 9.9 5.1 SO SRCPARAM KADUL03 1.600000E+06 10 300 17.5 6.1 SO SRCPARAM HARS1 1.000000E+00 30 1920 1560 0 0.00001 SOSRCPARAM HARS2 1.000000E+00 301620105000.00001 SO SRCPARAM HARS3 1.000000E+00 30 1950 1020 0 0.00001 SO SRCPARAM HARS4A 1.000000E+00 30 1500 1050 0 0.00001 SO SRCPARAM HARS4B 1.000000E+00 30 1500 1100 0 0.00001 SO SRCPARAM HARS5 1.000000E+00 30 1890 1560 0 0.00001 SO SRCPARAM HARS6 1.000000E+00 30 1500 1800 0 0.00001 SO SRCPARAM HARS7 1.000000E+00 30 450 1470 0 0.00001 SO SRCPARAM HARS14A 1.000000E+00 30 1530 1500 57 0.00001 SO SRC PARA M HARS14B 1.000000E+00 30 1530 1500 57 0.00001 SO SRCPARAM HARS15 1.000000E+00 30 450 1170 67 0.00001 SO SRC PARA M HARS16A 1.000000E+00 30 1275 1050 21 0.00001 A1-2 SO SRCPARAM HARS16B 1.000000E+00 30 1275 1050 21 0.00001 SO SRCPARAM HARW1 1.000000E+00 30 420 390 0 0.00001 SO SRC PARA M HARW2 1.000000E+00 30 420 900 0 0.00001 SO SRC PARA M HARW3 1.000000E+00 30 450 450 0 0.00001 SO SRC PARA M HARW4 1.000000E+00 30 300 450 0 0.00001 SO SRCPARAM HARW5 1.000000E+00 30 300 450 0 0.00001 SO SRCPARAM HARW6 1.000000E+00 30 300 300 0 0.00001 SO SRC PARA M HARW7 1.000000E+00 30 300 300 90 0.00001 SO SRCPARAM HARW8 1.000000E+00 30 300 300 0 0.00001 SO SRCPARAM HARW9 1.000000E+00 30 300 300 0 0.00001 SO SRCPARAM HARW10 1.000000E+00 30 300 300 0 0.00001 SO SRCPARAM HARWU 1.000000E+00 30 300 300 0 0.00001 SO SRCPARAM HARWT 1.000000E+00 30 450 240 16 0.00001 SO SRCPARAM HARWFU 1.000000E+00 30 360 570 28 0.00001 SO SRCPARAM HARWY 1.000000E+00 30 450 330 21 0.00001 SO SRCPARAM HARWW 1.000000E+00 30 390 180 90 0.00001 SO SRCPARAM HARWX 1.000000E+00 30 390 270 51 0.00001 SO SRCPARAM HARUHA1 2.200000E+06 12 300 22.9 4.5 SO SRCPARAM HARUHV3 1.200000E+06 16 300 31.9 4 SO SRCPARAM HARUH4A 8.400000E+05 16 300 22.8 4 SO SRCPARAM HARUHUN 7.500000E+05 1 300 26 3.5 SO SRCPARAM HARUHM2 1.600000E+06 8.2 300 21.3 4 SO SRCPARAM HARUH5A 2.100000E+05 10 300 7 1.1 SO SRCPARAM HARUFS5 2.100000E+06 13 300 16.7 8.9 SO SRCPARAM HARUFS4 2.200000E+06 13 300 17.1 8.9 SO SRCPARAM HARUHM5 2.200000E+06 13 300 17.5 8.9 SO SRCPARAM HARUHM6 1.600000E+06 13 300 15.3 6.6 SO SRCPARAM HARUHM7 9.000000E+05 13 300 19 4.4 SO SRCPARAM HARUHM8 9.000000E+05 13 300 19 4.4 SO SRCPARAM LORS1 1.000000E+00 30 780 1500 0 0.00001 SO SRC PARA M LORS2 1.000000E+00 30 990 1000 0 0.00001 SO SRC PARA M LORS3 1.000000E+00 30 240 210 0 0.00001 SO SRCPARAM LORW1 1.000000E+00 30 780 480 0 0.00001 SO SRCPARAM LORW2 1.000000E+00 30 600 480 0 0.00001 SO SRCPARAM LORU2 1.000000E+06 14.4 300 8.79 7.1 SO EMISUNIT 1 BQ/M2/SEC BO/M3 SO SRCGROUP ARM ARMS7 A ARMS7B ARMUAM1 ARMUAM2 ARMUAM3 ARMUAM6 ARMUAM7 SO SRCGROUP FSO FSOS10 FSOS11 FSOS12 FSOS13 FSOS17 FSOS2A FSOS2B FSOS2C SO SRCGROUP FSO FSOS2D FSOS3 FSOS4 FSOS5A FSOS5B FSOS6 FSOS8A FSOS8B SO SRCGROUP FSO FSOS8C FSOS9 FSOUB1 E FSOUB1W FSOUMAE FSOUMAK FSOUMAN SO SRCGROUP FSO FSOUMAS FSOUTSE FSOWC FSOWD FSOWE FSOWF FSOWG FSOWH SO SRCGROUP FSO FSOWI FSOWJ FSOWK FSOWL FSOWM FSOWN FSOWO FSOWR FSOWS SO SRCGROUP HARMONY HARS1 HARS14A HARS14B HARS15 HARS16A HARS16B HARS2 SO SRCGROUP HARMONY HARS3 HARS4A HARS4B HARS5 HARS6 HARS7 HARUFS4 HARUFS5 SO SRCGROUP HARMONY HARUH4A HARUH5A HARUHA1 HARUHM2 HARUHM5 HARUHM6 HARUHM7 SO SRCGROUP HARMONY HARUHM8 HARUHUN HARUHV3 HARW1 HARW10 HARW2 HARW3 HARW4 SO SRCGROUP HARMONY HARW5 HARW6 HARW7 HARW8 HARW9 HARWFU HARWT HARWU HARWV SO SRCGROUP HARMONY HARWW HARWX SO SRCGROUP LOR LORS1 LORS2 LORS3 LORU2 LORW1 LORW2 SO SRCGROUP KAD KADS1 KADUFR7 KADUL03 KADUST1 KADUST2 KADWA KADWB SO SRCGROUP KAD KADWL3 KADWP KADWO SO SRCGROUP FREE ARMS7A ARMS7B ARMUAM1 ARMUAM2 ARMUAM3 ARMUAM6 ARMUAM7 SO SRCGROUP FREE FSOS10 FSOS11 FSOS12 FSOS13 FSOS17 FSOS2A FSOS2B FSOS2C SO SRCGROUP FREE FSOS2D FSOS3 FSOS4 FSOS5A FSOS5B FSOS6 FSOS8A FSOS8B SO SRCGROUP FREE FSOS8C FSOS9 FSOUB1 E FSOUB1W FSOUMAE FSOUMAK FSOUMAN SO SRCGROUP FREE FSOUMAS FSOUTSE FSOWC FSOWD FSOWE FSOWF FSOWG FSOWH SO SRCGROUP FREE FSOWI FSOWJ FSOWK FSOWL FSOWM FSOWN FSOWO FSOWR FSOWS SO SRCGROUP FREE HARS1 HARS14A HARS14B HARS15 HARS16A HARS16B HARS2 SO SRCGROUP FREE HARS3 HARS4A HARS4B HARS5 HARS6 HARS7 HARUFS4 HARUFS5 SO SRCGROUP FREE HARUH4A HARUH5A HARUHA1 HARUHM2 HARUHM5 HARUHM6 HARUHM7 SO SRCGROUP FREE HARUHM8 HARUHUN HARUHV3 HARW1 HARW10 HARW2 HARW3 HARW4 SO SRCGROUP FREE HARW5 HARW6 HARW7 HARW8 HARW9 HARWFU HARWT HARWU HARWV SO SRCGROUP FREE HARWW HARWX KADS1 KADUFR7 KADUL03 KADUST1 KADUST2 SO SRCGROUP FREE KADWA KADWB KADWL3 KADWP KADWO LORS1 LORS2 LORS3 LORU2 SO SRCGROUP FREE LORW1 LORW2 SO SRCGROUP NL57 ARMS7 A ARMS7B ARMUAM1 ARMUAM2 ARMUAM3 ARMUAM6 ARMUAM7 SO SRCGROUP NL57 FSOS10 FSOS11 FSOS12 FSOS13 FSOS17 FSOS2A FSOS2B FSOS2C SO SRCGROUP NL57 FSOS2D FSOS3 FSOS4 FSOS5A FSOS5B FSOS6 FSOS8A FSOS8B SO SRCGROUP NL57 FSOS8C FSOS9 FSOUB1E FSOUB1W FSOUMAE FSOUMAK FSOUMAN SO SRCGROUP NL57 FSOUMAS FSOUTSE FSOWC FSOWD FSOWE FSOWF FSOWG FSOWH SO SRCGROUP NL57 FSOWI FSOWJ FSOWK FSOWL FSOWM FSOWN FSOWO FSOWR FSOWS SO FINISHED RE STARTING RE GRIDCART CART1 STA RE GRIDCART CART1 XYINC -5000 26 1500 -9000 33 1500 RE GRIDCART CART1 END RE FINISHED ME STARTING ME INPUTFIL C:IBREEZElFSOIFSOMET.ASC FREE ME ANEMHGHT 10.0 METERS ME SURFDATA 12345 1997 ME UAIRDATA 12345 1997 ME STARTEND 97 01 01 1 97 12 31 24 MEWDROTATE 180.0 MEWINDCATS 1.54 3.09 5.14 8.23 10.80 ME FINISHED OU STARTING OU PLOTFILE ANNUAL ARM C:IBREEZElFSOIARM.DAT OU PLOTFILE ANNUAL FSO C:IBREEZElFSOIFSO.DAT OU PLOTFILE ANNUAL HARMONY C:IBREEZElFSOIHARMONY.DAT OU PLOTFILE ANNUAL LOR C:IBREEZElFSOILOR.DAT OU PLOTFILE ANNUAL KAD C:IBREEZElFSOIKAD.DAT OU PLOTFILE ANNUAL FREE C:IBREEZElFSOIFREE.DAT OU PLOTFILE ANNUAL NL57 C:IBREEZEIFSOINL57.DAT OU FINISHED ••• Message Summary For ISC3 Model Setup ••• A1-3 ••••••••. Summary of Total Messages •••••••• A Total of o Fatal Error Message(s) A Total of oWarning Message(s) A Total of o Informational Message(s) ------- FATAL ERROR MESSAGES ---_ ••• -- NONE ._. ------. WARNING MESSAGES -- NONE ._- --- SETUP Finishes Successfully --- ---ISCST3- VERSION 96113 --- --- ANGLOGOLD· FREE STATE OPERATIONS 12/10/98 ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE --MODELOPTs: CONC RURAL FLAT FLGPOL MODEL SETUP OPTIONS SUMMARY "·Intermediate Terrain Processing is Selected --Model Is Setup For Calculation of Average CONCentration Values . .. SCAVENGING/DEPOSITION LOGIC .. --Model Uses NO DRY DEPLETION. DDPLETE = F --Model Uses NO WET DEPLETION. WDPLETE = F --NO WET SCAVENGING Data Provided. --Model Does NOT Use GRIDDED TERRAIN Data for Depletion Calculations --Model Uses RURAL Dispersion. --Model Uses User-Specified Options: 1. Final Plume Rise. 2. Stack-tip Downwash. 3. Buoyancy-induced Dispersion. 4. Calms Processing Routine. 5. Not Use Missing Data Processing Routine. 6. Default Wind Profile Exponents. 7. Default Vertical Potential Temperature Gradients. UModel Assumes Receptors on FLAT Terrain. -·Model Accepts FLAGPOLE Receptor Heights. --Model Calculates ANNUAL Averages Only "This Run Includes: 104 Source(s); 7 Source Group(s); and 858 Receptor(s) "The Model Assumes A Pollutant Type of: RADON --Model Set To Continue RUNning After the Setup Testing. ·-Output Options Selected: Model Outputs Tables of ANNUAL Averages by Receptor Model Outputs External File(s) of High Values for Plotting (PLOTFILE Keyword) ·-NOTE: The Following Flags May Appear Following CONC Values: c for Calm Hours m for Missing Hours b for Both Calm and Missing Hours -·Misc. Inputs: Anem. Hgt. (m) = 10.00; Decay Coef. = .2097E·05; Rot. Angle = 180.0 Emission Units = BO/M2/SEC Emission Rate Unit Factor = 1.0000 Output Units = BO/M3 --Input Runstream File: C:IBREEZEIFSOIFSO.INP , -·Output Print File: C:IBREEZE\FSOIFSO.LST --- ISCST3 • VERSION 96113 ••• ._. ANGLOGOLD· FREE STA TE OPERATIONS 12/10/98 ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 2 ··MODELOPTs: CONC RURAL FLAT FLGPOL _.- POINT SOURCE DATA •• - NUMBER EMISSION RATE BASE STACK STACK STACK STACK BUILDING EMISSION RATE SOURCE PART. (USER UNITS) X Y ELEV. HEIGHT TEMP. EXIT VEL. DIAMETER EXISTS SCALAR VARY ID CATS. (METERS) (METERS) (METERS) (METERS) (DEG.K) (M/SEC) (METERS) BY ------------------------------------ .. -.--------------------. FSOUB1E 0 .25000E+07 17420.0 5450.0 .0 13.44 300.00 28.60 6.00 NO FSOUB1W 0 .11000E+07 15870.0 6570.0 .0 13.00 300.00 10.00 6.70 NO FSOUTSE 0 .27000E+07 8450.0 24750.0 .0 12.20 300.00 14.30 6.90 NO FSOUMAN 0 .19000E+07 4870.0 21240.0 .0 15.00 300.00 15.30 7.20 NO FSOUMAE 0 .19000E+07 8450.0 17690.0 .0 15.00 300.00 9.10 9.50 NO FSOUMAS 0 .17000E+07 6420.0 16450.0 .0 10.00 300.00 14.30 7.10 NO FSOUMAK 0 .30000E+06 6180.0 17700.0 .0 10.00 300.00 5.10 4.90 NO ARMUAM1 0 .30000E+06 13180.0 16690.0 .0 7.00 300.00 3.00 6.00 NO ARMUAM2 0 .90000E+06 12780.0 14300.0 .0 14.00 300.00 18.20 4.70 NO ARMUAM3 0 .40000E+06 12210.0 13240.0 .0 12.50 300.00 4.20 6.00 NO ARMUAM6 0 .10000E+07 8960.0 12720.0 .0 14.00 300.00 10.90 6.40 NO ARMUAM7 0 .80000E+06 7180.0 13360.0 .0 14.00 300.00 8.60 6.40 NO KADUST1 0 .80000E+06 15870.0 11330.0 .0 13.00 300.00 6.10 7.40 NO KADUST2 0 .80000E+06 16720.0 8510.0 .0 12.00 300.00 6.60 7.40 NO KADUFR7 0 .6oo00E+06 2600.0 24700.0 .0 13.00 300.00 9.90 5.10 NO KADUL03 0 .16000E+07 2270.0 29300.0 0 10.00 300.00 17.50 6.10 NO A1-4 HARUHA1 0 .22000E+07 24500.0 690.0 .0 12.00 300.00 22.90 4.50 NO HARUHV3 0 .12000E+07 28000.0 -1810.0 .0 16.00 300.00 31.90 4.00 NO HARUH4A 0 .84000E+06 25300.0 3540.0 .0 16.00 300.00 22.80 4.00 NO HARUHUN 0 .75000E+06 16000.0 3000.0 .0 1.00 300.00 26.00 3.50 NO HARUHM2 0 .16000E+07 23900.0 -4540.0 .0 8.20 300.00 21.30 4.00 NO HARUH5A 0 .21000E+06 28300.0 2810.0 .0 10.00 300.00 7.00 1.10 NO HARUFS5 0 .21000E+07 24720.0 12870.0 .0 13.00 300.00 16.70 8.90 NO HARUFS4 0 .22000E+07 22870.0 10480.0 .0 13.00 300.00 17.10 8.90 NO HARUHM5 0 .22000E+07 13390.0 3000.0 .0 13.00 300.00 17.50 8.90 NO HARUHM6 0 .16000E+07 13660.0 6930.0 .0 13.00 300.00 15.30 6.60 NO HARUHM7 0 .90000E+06 12750.0 10690.0 .0 13.00 300.00 19.00 4.40 NO HARUHM8 0 .90000E+06 11720.0 9600.0 .0 13.00 300.00 19.00 4.40 NO LORU2 0 .10000E+07 1210.0 36000.0 .0 14.40 300.00 8.79 7.10 NO ••• ISCST3 - VERSION 96113 ••• ••• ANGLOGOLD - FREE STATE OPERATIONS 12/10/98 ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 3 ··MODELOPTs: CONC RURAL FLAT FLGPOL .- AREA SOURCE DATA ••• NUMBER EMISSION RATE COORD (SW CORNER) BASE RELEASE X-DIM Y-DIM ORIENT. INIT. EMISSION RATE SOURCE PART. (USER UNITS X Y ELEV. HEIGHT OF AREA OF AREA OF AREA SZ SCALAR VARY ID CATS. /METER"2) (METERS) (METERS) (METERS) (METERS) (METERS) (METERS) (DEG.) (METERS) BY --------------------------------------------------------------- FSOS2A 0 .10000E+01 3000.0 20330.0 .0 30.00 1260.00 1350.00 90.00 .00 FSOS2B 0 .10000E+01 3000.0 19060.0 .0 30.00 1260.00 1350.00 90.00 .00 FSOS2C 0 .10000E+01 4330.0 20330.0 .0 30.00 1260.00 1350.00 90.00 .00 FSOS2D 0 .10000E+01 4330.0 19060.0 .0 30.00 1260.00 1350.00 90.00 .00 FSOS3 0 .10000E+01 4240.0 17780.0 .0 30.00 990.00 1470.00 90.00 .00 FSOS4 0 .10000E+01 6810.0 19780.0 .0 30.00 900.00 1320.00 90.00 .00 FSOS5A 0 .10000E+01 6300.0 15600.0 .0 30.00 1065.00 1200.00 67.00 .00 FSOS5B 0 .10000E+01 6690.0 14630.0 .0 30.00 1065.00 1200.00 67.00 .00 FSOS6 0 .10000E+01 4300.0 13360.0 .0 30.00 990.00 1890.00 52.00 .00 FSOS8A 0 .10000E+01 16720.0 11420.0 .0 30.00 1230.00 810.00 74.00 00 FSOS8B 0 .10000E+01 17060.0 10210.0 .0 30.00 1230.00 810.00 74.00 .00 FSOS8C 0 .10000E+01 17420.0 8930.0 .0 30.00 1230.00 810.00 74.00 .00 FSOS9 0 .10000E+01 15480.0 7720.0 .0 30.00 690.00 1740.00 71.00 .00 FSOS10 0 .10000E+01 12210.0 5150.0 .0 30.00 1980.00 1650.00 68.00 .00 FSOS11 0 .10000E+01 14750.0 5210.0 .0 30.00 1560.00 1110.00 55.00 .00 FSOS12 0 .10000E+01 16540.0 7060.0 .0 30.00 1710.00 810.00 70.00 .00 FSOS13 0 .10000E+01 17690.0 6540.0 .0 30.00 1140.00 720.00 70.00 .00 FSOS17 0 .10000E+01 13330.0 6360.0 .0 30.00 960.00 690.00 45.00 .00 FSOWC 0 .10000E+01 8600.0 25090.0 .0 30.00 165.00 420.00 90.00 .00 FSOWD 0 .10000E+01 5930.0 22360.0 .0 30.00 255.00 270.00 62.00 .00 FSOWE 0 .10000E+01 4090.0 21060.0 .0 30.00 330.00 600.00 48.00 .00 FSOWF 0 .10000E+01 7120.0 20600.0 .0 30.00 300.00 450.00 56.00 .00 FSOWG 0 .10000E+01 6060.0 16090.0 .0 30.00 240.00 480.00 24.00 .00 FSOWH 0 .10000E+01 8090.0 17420.0 .0 30.00 240.00 390.00 39.00 .00 FSOWI 0 .10000E+01 6420.0 13540.0 .0 30.00 630.00 270.00 16.00 .00 FSOWJ 0 .10000E+01 7810.0 15300.0 .0 30.00 960.00 210.00 66.00 .00 FSOWK 0 .10000E+01 8240.0 12780.0 .0 30.00 570.00 300.00 7.00 .00 FSOWL 0 .10000E+01 13240.0 16720.0 .0 30.00 420.00 600.00 29.00 .00 FSOWM 0 .10000E+01 12330.0 13240.0 .0 30.00 510.00 270.00 25.00 .00 FSOWN 0 .10000E+01 13600.0 14480.0 .0 30.00 330.00 420.00 90.00 .00 FSOWO 0 .10000E+01 11900.0 9150.0 .0 30.00 540.00 390.00 26.00 .00 FSOWR 0 .10000E+01 13750.0 6840.0 .0 30.00 660.00 360.00 8.00 .00 FSOWS 0 .10000E+01 15930.0 6660.0 .0 30.00 360.00 390.00 70.00 .00 ARMS7A 0 .10000E+01 13510.0 15630.0 .0 30.00 1230.00 1125.00 24.00 .00 ARMS7B 0 .10000E+01 13960.0 16660.0 .0 30.00 1230.00 1125.00 24.00 .00 KADS1 0 .10000E+01 3420.0 29000.0 .0 30.00 1000.00 1290.00 90.00 .00 KADWA 0 .10000E+01 4090.0 27060.0 .0 30.00 600.00 300.00 65.00 .00 KADWB 0 .10000E+01 4600.0 25000.0 .0 30.00 180.00 240.00 85.00 .00 KADWP 0 .10000E+01 15660.0 11210.0 .0 30.00 600.00 420.00 69.00 .00 KADWQ 0 .10000E+01 15720.0 8570.0 .0 30.00 450.00 600.00 28.00 .00 ••• ISCST3 - VERSION 96113 ••• ••• ANGLOGOLD - FREE STATE OPERATIONS 12/10198 ••• ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 4 "MODELOPTs: CONC RURAL FLAT FLGPOL ••• AREA SOURCE DATA ••• NUMBER EMISSION RATE COORD (SW CORNER) BASE RELEASE X-DIM Y-DIM ORIENT. INIT. EMISSION RATE SOURCE PART. (USER UNITS X Y ELEV. HEIGHT OF AREA OF AREA OF AREA SZ SCALAR VARY ID CATS. /METER"2) (METERS) (METERS) (METERS) (METERS) (METERS) (METERS) (DEG.) (METERS) BY KADWL3 o .10000E+01 1000.0 29120.0 .0 30.00 450.00 540.00 .00 .00 HARS1 o .10000E+01 20120.0 2360.0 .0 30.00 1920.00 1560.00 .00 .00 HARS2 o .10000E+01 20120.0 900.0 .0 30.00 1620.00 1050.00 .00 .00 HARS3 o .10000E+01 25240.0 1660.0 .0 30.00 1950.00 1020.00 .00 .00 HARS4A o .10000E+01 25090.0 -3480.0 .0 30.00 1500.00 1050.00 .00 .00 HARS4B o .10000E+01 25090.0 -2450.0 .0 30.00 1500.00 1100.00 .00 00 HARS5 o .10000E+01 23090.0 -4120.0 .0 30.00 1890.00 1560.00 .00 .00 HARS6 o .10000E+01 20780.0 -6000.0 .0 30.00 1500.00 1800.00 .00 00 HARS7 o .10000E+01 22240.0 -6000.0 .0 30.00 450.00 1470.00 .00 .00 HARS14A o .10000E+01 19840.0 8840.0 .0 30.00 1530.00 1500.00 57.00 .00 HARS14B o .10000E+01 21150.0 9660.0 .0 30.00 1530.00 1500.00 57.00 .00 HARS15 o .10000E+01 21660.0 6600.0 .0 30.00 450.00 1170.00 67.00 .00 HARS16A o .10000E+01 21810.0 5300.0 .0 30.00 1275.00 1050.00 21.00 .00 HARS16B o .10000E+01 23000.0 4840.0 .0 30.00 1275.00 1050.00 21.00 .00 HARW1 o .10000E+01 22000.0 2150.0 .0 30.00 420.00 390.00 .00 .00 HARW2 o .10000E+01 22000.0 1000.0 .0 30.00 420.00 900.00 .00 .00 HARW3 o .10000E+01 22780.0 -120.0 .0 30.00 450.00 450.00 .00 .00 HARW4 o .10000E+01 25450.0 -1000.0 .0 30.00 300.00 450.00 .00 .00 HARW5 o .10000E+01 26510.0 -720.0 .0 30.00 300.00 450.00 .00 .00 HARW6 o .10000E+01 22150.0 -3630.0 .0 30.00 300.00 300.00 .00 .00 A1-5 HARW7 0 .10000E+01 24000.0 -4300.0 .0 30.00 300.00 300.00 90.00 .00 HARW8 0 .10000E+01 25240.0 -3930.0 .0 30.00 300.00 300.00 .00 .00 HARW9 0 .10000E+01 25450.0 3450.0 .0 30.00 300.00 300.00 .00 .00 HARW10 0 .10000E+01 12390.0 10300.0 .0 30.00 300.00 300.00 .00 .00 HARWU 0 .10000E+01 16000.0 2660.0 .0 30.00 300.00 300.00 .00 .00 HARWT 0 .10000E+01 13430.0 2720.0 .0 30.00 450.00 240.00 16.00 .00 HARWFU 0 .10000E+01 20600.0 7060.0 .0 30.00 360.00 570.00 28.00 .00 HARWV 0 .10000E+01 23810.0 5690.0 .0 30.00 450.00 330.00 21.00 .00 HARWW 0 .10000E+01 22810.0 11240.0 .0 30.00 390.00 180.00 90.00 .00 HARWX 0 .10000E+01 24360.0 13360.0 .0 30.00 390.00 270.00 51.00 .00 LORS1 0 .10000E+01 -570.0 33000.0 .0 30.00 780.00 1500.00 .00 .00 LORS2 0 .10000E+01 -90.0 32000.0 .0 30.00 990.00 1000.00 .00 .00 LORS3 0 .10000E+01 1000.0 35320.0 .0 30.00 240.00 210.00 .00 .00 LORW1 0 .10000E+01 1270.0 35510.0 .0 30.00 780.00 480.00 .00 .00 LORW2 0 .10000E+01 1270.0 33750.0 .0 30.00 600.00 480.00 .00 .00 ••• ISCST3 - VERSION 96113 ••• ••• ANGLOGOLD - FREE STATE OPERATIONS 12110/98 _. ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 5 "MODELOPTs: CONC RURAL FLAT FLGPOL ••• SOURCE IDs DEFINING SOURCE GROUPS ••• GROUP ID SOURCE IDs ARM ARMS7A. ARMS7B ,ARMUAM1 , ARMUAM2 , ARMUAM3 , ARMUAM6, ARMUAM7 , FSO FSOS2A, FSOS2B ,FSOS2C ,FSOS2D ,FSOS3 ,FSOS4 ,FSOS5A ,FSOS5B ,FSOS6 ,FSOS8A ,FSOS8B , FSOS8C , FSOS9 ,FSOS10 ,FSOS11 ,FSOS12 ,FSOS13 ,FSOS17 ,FSOWC ,FSOWD ,FSOWE ,FSOWF ,FSOWG ,FSOWH , FSOWI ,FSOWJ ,FSOWK ,FSOWL ,FSOWM ,FSOWN ,FSOWO ,FSOWR ,FSOWS ,FSOUB1E, FSOUB1W, FSOUTSE, FSOUMAN,FSOUMAE,FSOUMAS, FSOUMAK, HARMONY HARS1 ,HARS2 ,HARS3 ,HARS4A ,HARS4B ,HARS5 ,HARS6 ,HARS7 ,HARS14A, HARS14B, HARS15 , HARS16A, HARS16B ,HARW1 ,HARW2 ,HARW3 ,HARW4 ,HARW5 ,HARW6 ,HARW7 ,HARW8 ,HARW9 ,HARW1 0 ,HARWU , HARWT ,HARWFU ,HARWV ,HARWW ,HARWX ,HARUHA1 ,HARUHV3,HARUH4A,HARUHUN,HARUHM2,HARUH5A,HARUFS5, HARUFS4,HARUHM5,HARUHM6,HARUHM7,HARUHM8, LOR LORS1, LORS2 ,LORS3 ,LORW1 ,LORW2 ,LORU2 KAD KADS1, KADWA ,KADWB ,KAONP ,KADWQ ,KADWL3 ,KADUST1 , KADUST2 , KADUFR7 , KADUL03 , FREE FSOS2A, FSOS2B ,FSOS2C ,FSOS2D ,FSOS3 ,FSOS4 ,FSOS5A, FSOS5B ,FSOS6 ,FSOS8A ,FSOS8B , FSOS8C FSOS9 ,FSOS10 ,FSOS11 ,FSOS12 ,FSOS13 ,FSOS17 ,FSOWC ,FSOWD ,FSOWE ,FSOWF ,FSOWG ,FSOWH , FSOWI ,FSOWJ ,FSOWK ,FSOWL ,FSOWM ,FSOWN ,FSOWO ,FSOWR ,FSOWS ,FSOUB1E, FSOUB1W , FSOUTSE , FSOUMAN , FSOUMAE , FSOUMAS , FSOUMAK ,ARMS7A ,ARMS7B ,ARMUAM1 , ARMUAM2 , ARMUAM3 , ARMUAM6 , ARMUAM7 . KADS1 KAONA ,KADWB ,KADWP ,KAONQ ,KADWL3 , KADUST1 , KADUST2 , KADUFR7 , KADUL03 ,HARS1 ,HARS2 ,HARS3 , HARS4A ,HARS4B ,HARS5 ,HARS6 ,HARS7 ,HARS14A, HARS14B, HARS15 ,HARS16A, HARS16B, HARW1 ,HARW2 HARW3 ,HARW4 ,HARW5 ,HARW6 ,HARW7 ,HARW8 ,HARW9 ,HARW10 ,HARWU ,HARWT ,HARWFU ,HARWV HARWW ,HARWX ,HARUHA1 ,HARUHV3,HARUH4A,HARUHUN,HARUHM2,HARUH5A,HARUFSS,HARUFS4,HARUHM5,HARUHM6, HARUHM7 , HARUHM8 ,LORS1 ,LORS2 ,LORS3 ,LORW1 ,LORW2 ,LORU2 , "'ISCST3 - VERSION 96113 •••••• ANGLOGOLD - FREE STATE OPERATIONS 12110/98 _. ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 6 "MODELOPTs: CONC RURAL FLAT FLGPOL ••• SOURCE IDs DEFINING SOURCE GROUPS ... GROUP ID SOURCE IDs NL57 FSOS2A, FSOS2B ,FSOS2C ,FSOS2D ,FSOS3 ,FSOS4 ,FSOS5A ,FSOS5B ,FSOS6 ,FSOS8A , FSOS8B ,FSOS8C , FSOS9 ,FSOS10 ,FSOS11 ,FSOS12 ,FSOS13 ,FSOS17 ,FSOWC ,FSOWD ,FSOWE ,FSOWF ,FSOWG ,FSOWH , FSOWI ,FSOWJ ,FSOWK ,FSOWL ,FSOWM ,FSOWN ,FSOWO ,FSOWR ,FSOWS ,FSOUB1E, FSOUB1W , FSOUTSE , FSOUMAN, FSOUMAE , FSOUMAS , FSOUMAK, ARMS7A ,ARMS7B ,ARMUAM1 , ARMUAM2 , ARMUAM3, ARMUAM6 , ARMUAM7 , "'ISCST3 - VERSION 96113'" ••• ANGLOGOLD - FREE STATE OPERATIONS 12110/98 _. ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 7 "MODELOPTs: CONC RURAL FLAT FLGPOL ••• GRIDDED RECEPTOR NETWORK SUMMARY'" m NETWORK ID: CART1 ; NETWORK TYPE: GRIDCART '" A1-6 ••• X-COORDINATES OF GRID ••• (METERS) -5000.0, -3500.0, -2000.0, -500.0, 1000.0, 2500.0, 4000.0, 5500.0, 7000.0, 8500.0, 10000.0, 11500.0, 13000.0, 14500.0, 16000.0, 17500.0, 19000.0, 20500.0, 22000.0, 23500.0, 25000.0, 26500.0, 28000.0, 29500.0, 31000.0, 32500.0, ••• Y-COORDINATES OF GRID ••• (METERS) -9000.0, -7500.0, -60000, -4500.0, -3000.0, -1500.0, .0, 1500.0, 3000.0, 4500.0, 6000.0, 7500.0, 90000, 10500.0, 12000.0, 13500.0, 15000.0, 16500.0, 18000.0, 19500.0, 21000.0, 22500.0, 24000.0, 25500.0, 27000.0, 28500.0, 30000.0, 31500.0, 33000.0, 34500.0, 36000.0, 375000, 39000.0, ••• ISCST3 - VERSION 96113 ••• ••• ANGLOGOLD - FREE STATE OPERATIONS 12/10/98 _. ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 8 ··MODELOPTs: CONC RURAL FLAT FLGPOL ••• NETWORK ID: CART1 ; NETWORK TYPE: GRIDCART ••• • RECEPTOR FLAGPOLE HEIGHTS IN METERS' Y-COORD I X-COORD (METERS) (METERS) I -5000.00 -3500.00 -2000.00 -500.00 1000.00 2500.00 4000.00 5500.00 7000.00 ------------------------------------------------------------------ 39000.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 37500.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 36000.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 34500.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 33000.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 31500.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 30000.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 28500.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 27000.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 25500.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 24000.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 22500.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 21000.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 19500.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 18000.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 16500.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 15000.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 13500.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 12000.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 10500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 9000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 7500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 6000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 4500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 3000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 .00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 -1500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 -3000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 -4500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 -6000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 -7500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 -9000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 ••• ISCST3 - VERSION 96113 ••• • •• ANGLOGOLD - FREE STATE OPERATIONS 12/10/98 ••• ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 9 "MODELOPTs: CONC RURAL FLAT FLGPOL ••• NETWORK ID: CART1 ; NETWORK TYPE: GRIDCART ••• • RECEPTOR FLAGPOLE HEIGHTS IN METERS· Y-COORD I X-COORD (METERS) (METERS) I 8500.00 10000.00 11500.00 13000.00 14500.00 16000.00 17500.00 19000.00 20500.00 ------------------------------------------------------------------ 39000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 37500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 36000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 34500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 33000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 31500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 30000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 28500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 27000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 25500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 24000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 22500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 21000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 19500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 18000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 16500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 15000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 13500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 12000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 10500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 9000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 7500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 6000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 4500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 3000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 A1-7 1500.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 .00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 -1500.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 -3000.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 -4500.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 -6000.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 -7500.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 -9000.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 ••• ISCST3 - VERSION 96113 ••• ••• ANGLOGOLD - FREE STATE OPERATIONS 12/10/98 W. ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 10 ··MODELOPTs: CONC RURAL FLAT FLGPOL ow NETWORK ID: CART1 ; NETWORK TYPE: GRIDCART ••• • RECEPTOR FLAGPOLE HEIGHTS IN METERS· Y-COORD I X-COORD (METERS) (METERS) I 22000.00 23500.00 25000.00 26500.00 28000.00 29500.00 31000.00 32500.00 ........ __ -----_-_---_-------_-----_.----------------------------- 39000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 37500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 36000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 34500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 33000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 31500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 30000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 28500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 27000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 25500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 24000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 22500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 21000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 19500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 18000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 16500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 15000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 13500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 12000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 10500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 9000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 7500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 6000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 4500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 3000.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1500.00 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 .00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 -1500.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 -3000.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 -4500.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 -6000.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 -7500.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 -9000.00 I 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 ••• ISCST3 - VERSION 96113 ••• • •• ANGLOGOLD - FREE STATE OPERATIONS 12/10/98 W. ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 11 ··MODELOPTs: CONC RURAL FLAT FLGPOL • SOURCE-RECEPTOR COMBINATIONS FOR WHICH CALCULATIONS MAY NOT BE PERFORMED· LESS THAN 1.0 METER OR 3·ZLB IN DISTANCE, OR WITHIN OPEN PIT SOURCE SOURCE - - RECEPTOR LOCATION - - DISTANCE ID XR (METERS) YR (METERS) (METERS) HARUHUN 16000.0 3000.0 .00 ···ISCST3 - VERSION 96113 ••• • •• ANGLOGOLD - FREE STATE OPERATIONS 12/10/98 W. ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 12 ··MODELOPTs: CONC RURAL FLAT FLGPOL ••• METEOROLOGICAL DAYS SELECTED FOR PROCESSING ••• (1=YES; O=NO) 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 1111111111 111111 METEOROLOG ICAL DATA PROCESSED BETWEEN START DA TE: 97 1 1 1 AND END DATE: 97123124 NOTE: METEOROLOGICAL DATA ACTUALLY PROCESSED WILL ALSO DEPEND ON WHAT IS INCLUDED IN THE DATA FILE. ••• UPPER BOUND OF FIRST THROUGH FIFTH WIND SPEED CATEGORIES ••• (METERS/SEC) 1.54, 3.09, 5.14, 8.23, 10.80, ••• WIND PROFILE EXPONENTS ••• A1-8 STABILITY WIND SPEED CATEGORY CATEGORY 1 2 3 4 5 6 A .70000E-01 .70000E-01 .70000E-01 .70000E-01 .70000E-01 .70000E-01 B .70000E-01 .70000E-01 .70000E-01 .70000E-01 .70000E-01 .70000E-01 C .10000E+00 .10000E+00 .10000E+00 .10000E+00 .10000E+00 .10000E+00 D .15000E+00 .15000E+00 .15000E+00 .15000E+00 .15000E+00 .15000E+00 E .35000E+00 .35000E+00 .35000E+00 .35000E+00 .35000E+00 .35000E+00 F .55000E+00 .55000E+00 .55000E+00 .55000E+00 .55000E+00 .55000E+00 ••• VERTICAL POTENTIAL TEMPERATURE GRADIENTS ••• (DEGREES KELVIN PER METER) STABILITY WIND SPEED CATEGORY CATEGORY 1 2 3 4 5 6 A .OOOOOE+OO .OOOOOE+OO .OOOOOE+OO .OOOOOE+OO .OOOOOE+OO .OOOOOE+OO B .OOOOOE+OO .OOOOOE+OO .OOOOOE+OO .OOOOOE+OO .OOOOOE+OO .OOOOOE+OO C .OOOOOE+OO .OOOOOE+OO .OOOOOE+OO .OOOOOE+OO .OOOOOE+OO .OOOOOE+OO D .OOOOOE+OO .OOOOOE+OO .OOOOOE+OO .OOOOOE+OO .OOOOOE+OO .OOOOOE+OO E .20000E-01 .20000E-01 .20000E-01 .20000E-01 .20000E-01 .20000E-01 F .35000E-01 .35000E-01 .35000E-01 .35000E-01 .35000E-01 .35000E-01 ••• ISCST3 - VERSION 96113 ••• • •• ANGLOGOLD - FREE STATE OPERATIONS 12/10/98 ••• ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 13 "MODELOPTs: CONC RURAL FLAT FLGPOL ••• THE FIRST 24 HOURS OF METEOROLOGICAL DATA ••• FILE: C:IBREEZEIFSOIFSOMET.ASC FORMAT: FREE SURFACE STATION NO.: 12345 UPPER AIR STATION NO.: 12345 NAME: UNKNOWN NAME: UNKNOWN YEAR: 1997 YEAR: 1997 FLOW SPEED TEMP STAB MIXING HEIGHT (M) USTAR M-O LENGTH ZoO IPCODE PRATE YEAR MONTH DAY HOUR VECTOR (MIS) (K) CLASS RURAL URBAN (MIS) (M) (M) (mm/HR) 97 1 111.0 1.50 291.0 5 100.0 100.0 .0000 .0 .0000 0 .00 97 2 149.0 2.10 290.0 4 100.0 100.0 .0000 .0 .0000 0 .00 97 3 105.0 1.90 289.0 5 100.0 100.0 .0000 .0 .0000 0 .00 97 4 345.0 1.70 288.0 3 100.0 100.0 .0000 .0 .0000 0 .00 97 5 339.0 3.10 290.0 6 100.0 100.0 .0000 .0 .0000 0 .00 97 6 324.0 2.30 293.0 5 100.0 100.0 .0000 .0 .0000 0 .00 97 7 288.0 1.20 296.0 1000.0 1000.0 .0000 .0 .0000 0 .00 97 8 15.0 1.30 299.0 1 1000.0 1000.0 .0000 .0 .0000 0 .00 97 9 11.0 1.90 300.0 1 1000.0 1000.0 .0000 .0 .0000 0 .00 97 10 277.0 3.10 302.0 1 1000.0 1000.0 .0000 .0 .0000 0 .00 97 1 11 263.0 4.20 302.0 2 1000.0 1000.0 .0000 .0 .0000 0 .00 97 12 251.0 4.80 303.0 3 1000.0 1000.0 .0000 .0 .0000 0 .00 97 13 258.0 5.40 304.0 3 1000.0 1000.0 .0000 .0 .0000 0 .00 97 14 257.0 5.60 304.0 2 1000.0 1000.0 .0000 .0 .0000 0 .00 97 15 257.0 4.90 304.0 2 1000.0 1000.0 .0000 .0 .0000 0 .00 97 16 229.0 4.30 303.0 3 1000.0 1000.0 .0000 .0 .0000 0 .00 97 17 223.0 5.20 301.0 5 1000.0 1000.0 .0000 .0 .0000 0 .00 97 18 214.0 3.90 299.0 6 1000.0 1000.0 .0000 .0 .0000 0 .00 97 19 251.0 4.20 297.0 1 100.0 100.0 .0000 .0 .0000 0 .00 97 20 158.0 3.60 294.0 2 100.0 100.0 .0000 .0 .0000 0 .00 97 21 81.0 3.00 292.0 5 100.0 100.0 .0000 .0 .0000 0 .00 97 22 94.0 2.30 293.0 6 100.0 100.0 .0000 .0 .0000 0 .00 97 23 103.0 2.00 293.0 6 100.0 100.0 .0000 .0 .0000 0 .00 97 1 24 103.0 2.00 293.0 6 100.0 100.0 .0000 .0 .0000 0 .00 ••• NOTES: STABILITY CLASS 1=A, 2=B, 3=C, 4=D, 5=E AND 6=F. FLOW VECTOR IS DIRECTION TOWARD WHICH WIND IS BLOWING . ••• ISCST3 - VERSION 96113 ••• ••• ANGLOGOLD - FREE STATE OPERATIONS 12/10/98 ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 14 "MODELOPTs: CONC RURAL FLAT FLGPOL ••• THE ANNUAL ( 8736 HRS) AVERAGE CONCENTRATION VALUES FOR SOURCE GROUP: ARM INCLUDING SOURCE(S): ARMS7A, ARMS7B ,ARMUAM1 , ARMUAM2 , ARMUAM3, ARMUAM6 , ARMUAM7 , -- NETWORK ID: CART1 ; NETWORK TYPE: GRIDCART '" " CONC OF RADON IN BQ/M3 Y-COORD I X-COORD (METERS) (METERS) I -5000.00 -3500.00 -2000.00 -500.00 1000.00 2500.00 4000.00 5500.00 7000.00 ---- __________________________________________ • ___________ A_AAA_A. 39000.00 I .02784 .02845 .03046 .03110 .03178 .02926 .02721 .02994 .03263 37500.00 I .02988 .02985 .03135 .03297 .03394 .03372 .02982 .03108 .03406 36000.00 I .03030 .03209 .03253 .03428 .03614 .03730 .03429 .03265 .03572 34500.00 I .03126 .03293 .03463 .03581 .03824 .03962 .03972 .03626 .03761 33000.00 I .03447 .03412 .03606 .03814 .03972 .04215 .04462 .04239 .04000 31500.00 I .03792 .03843 .03745 .03954 .04204 .04506 .04806 .04918 .04483 30000.00 I .04180 .04253 .04299 .04175 .04450 .04806 .05130 .05519 .05305 28500.00 I .04803 .04692 .04842 .04839 .04656 .05039 .05433 .05891 .06219 27000.00 I .05851 .05618 .05410 .05555 .05591 .05362 .05848 .06522 .07027 25500.00 I .06980 .07018 .06764 .06477 .06445 .06452 .06421 .07010 .07728 24000.00 I .08037 .08348 .08553 .08420 .08107 .07979 .07827 .07787 .08482 22500.00 I .08406 .08880 .09617 .10286 .10546 .10575 .10121 .10020 .10003 21000.00 I .09758 .10088 .10429 .10953 .12034 .13079 .14001 .14313 .14099 19500.00 I .10815 .11601 .12211 .13011 .13797 .14732 .16114 .18266 .20352 18000.00 I .11206 .12185 .12870 .13822 .15048 .16616 .18879 .20888 .24390 A1-9 16500.00 I .10440 .11393 .12845 .14595 .15520 .16677 .18566 .21376 .25710 15000.00 I .10121 .11309 .12665 .14164 .15918 .18689 .21051 .23129 .27914 13500.00 I .10315 .11386 .12657 .14206 .16092 .18261 .21309 .25740 .29660 12000.00 I .10419 .11373 .12402 .13842 .16012 .19218 .24526 .32386 .45837 10500.00 I .10314 .11540 .13042 .15446 .18417 .21802 .28506 .34693 .44497 9000.00 I .11121 .12644 .14495 .16634 .19731 .23606 .27223 .34335 .40150 7500.00 I .12029 .13418 .15242 .17272 .19948 .22933 .27342 .30990 .33703 6000.00 I .12258 .13615 .15449 .17049 .19756 .22841 .25432 .26610 .28925 4500.00 I .12185 .13955 .14932 .17246 .19713 .20742 .22404 .23929 .26419 3000.00 I .12532 .13363 .15323 .17251 .17809 .18987 .19408 .21858 .24144 1500.00 I .12117 .13834 .15224 .15365 .16239 .17118 .18640 .20646 .22483 .00 I .12628 .13544 .13634 .14468 .14748 .15746 .17507 .19218 .20884 -1500.00 I .12148 .12241 .12828 .12825 .14017 14948 .16666 18148 .19041 -3000.00 I .11071 11505 .11694 .12315 .13164 14588 .15320 17138 .17086 -4500.00 I .10500 .10629 .10795 .11900 .12656 .13979 .14654 .15934 .15602 -6000.00 I .09648 .09866 .10641 .11153 .12463 .12921 .14146 .14544 .14407 -7500.00 I .09103 .09469 .10227 .11068 .11852 .12323 .13392 .13311 .13400 -9000.00 I .08655 .09325 .09721 .10916 .11130 .11983 .12486 .12349 .12579 ... ISCST3 - VERSION 96113'" ... ANGLOGOLD - FREE STATE OPERATIONS 12110/98 _. ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 15 "MODELOPTs: CONC RURAL FLAT FLGPOL ... THE ANNUAL ( 8736 HRS) AVERAGE CONCENTRATION VALUES FOR SOURCE GROUP: ARM INCLUDING SOURCE(S): ARMS7A. ARMS78 . ARMUAM1 . ARMUAM2. ARMUAM3. ARMUAM6. ARMUAM7 . ... NETWORK ID: CART1 ; NETWORK TYPE: GRIDCART ... - CONC OF RADON IN 801M3 Y-COORD I X-COORD (METERS) (METERS) I 8500.00 10000.00 11500.00 13000.00 14500.00 16000.00 17500.00 19000.00 20500.00 39000.00 .03670 .03788 .03982 .04345 .04590 .04592 .04288 .04820 .04785 37500.00 .03850 .04060 .04260 .04685 .04911 .04903 .04699 .05234 .05090 36000.00 .04010 .04395 .04584 .05054 .05294 .05251 .05239 .05663 .05422 34500.00 .04190 .04772 .04967 .05457 .05743 .05656 .05871 .06175 .05797 33000.00 .04404 .05135 .05429 .05923 .06253 .06191 .06548 .06696 .06270 31500.00 .04681 .05476 .05994 .06507 .06829 .06904 .07341 .07238 .06730 30000.00 .05090 .05864 .06657 .07252 .07571 .07798 .08275 .07888 .07353 28500.00 .05873 .06337 .07367 .08122 .08650 .08936 .09497 .08645 .08253 27000.00 .07085 .06981 .08148 .09078 .10090 .10279 .10740 .09769 .09327 25500.00 .08501 .08458 .09128 .10433 .11919 .12157 .12127 .11308 .10357 24000.00 .09785 .10478 .10562 .12391 .14601 .15061 .14229 .12910 .12129 22500.00 .11053 .12797 .13355 .14868 .18672 .19248 .17159 .15646 .13651 21000.00 .14125 .15365 .17685 .19009 .24404 .24977 .22021 .18297 .14355 19500.00 .22445 .22833 .24285 .28135 .35445 .36227 .27724 .19637 .14617 18000.00 .30552 .38302 .43686 .52056 .72391 .55444 .30929 .20481 .14857 16500.00 .32669 .44010 .64190 1.47968 2.03167 .77999 .35365 .22984 .16948 15000.00 .37084 .48774 .72414 1.36608 1.72411 .64719 .34223 .23197 .17585 13500.00 .43372 .57248 .77060 1.11273 .88695 .48995 .30694 .21553 .16599 12000.00 .55586 .62339 .72200 .77989 .60128 .37945 .27711 .20301 .15546 10500.00 .49860 .48716 .58345 .55830 .44045 .29988 .23643 .18783 .14867 9000.00 .41027 .42824 .47510 .43318 .34599 .25319 .20273 .17089 .13698 7500.00 .35088 .37591 .38849 .35608 .28700 .21140 .17933 .15364 .13186 6000.00 .31528 .31949 .33018 .30293 .24324 .18430 .16349 .13474 .12402 4500.00 .28774 .27834 .28669 .26144 .21231 .16103 .14893 .12648 .11056 3000.00 .25662 .24180 .25090 .22881 .18662 .14535 .13335 .11937 .10477 1500.00 .22454 .21300 .22013 .20256 .16577 .13345 .12024 .10996 .09809 .00 I .19940 .19205 .19639 .18189 .14817 .12225 .11204 .10218 .09195 -1500.00 I .17951 .17535 .17785 .16546 .13420 .11106 .10445 .09604 .08567 -3000.00 I .16321 .16085 .16239 .15070 .12244 .10135 .09732 .09130 .08143 -4500.00 I .15090 .14832 .14897 .13781 .11357 .09382 .08942 .08619 .07886 -6000.00 I .14054 .13746 .13733 .12685 .10585 .08729 .08238 .08100 .07616 -7500.00 I .13088 .12799 .12721 .11747 .09904 .08235 .07650 .07572 .07266 -9000.00 I .12199 .11969 .11825 .10908 .09283 .07813 .07124 .07085 .06873 "'ISCST3 - VERSION 96113'" ... ANGLOGOLD - FREE STATE OPERATIONS 12110/98 ... ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 16 "MODELOPTs: CONC RURAL FLAT FLGPOL '''THE ANNUAL ( 8736 HRS) AVERAGE CONCENTRATION VALUES FOR SOURCE GROUP: ARM INCLUDING SOURCE(S): ARMS7A. ARMS78 . ARMUAM1 . ARMUAM2. ARMUAM3. ARMUAM6. ARMUAM7 . ... NETWORK ID: CART1 ; NETWORK TYPE: GRIDCART'" - CONC OF RADON IN 801M3 Y-COORD I X-COORD (METERS) (METERS) I 22000.00 23500.00 25000.00 26500.00 28000.00 29500.00 31000.00 32500.00 39000.00 .04595 .04362 .04211 .04191 .03991 .03846 .03817 .03724 37500.00 .04885 .04589 .04535 .04424 .04154 .04147 .04044 .03913 36000.00 .05171 .04904 .04885 .04583 .04509 .04418 .04261 .04148 34500.00 .05474 .05359 .05152 .04911 .04862 .04673 .04518 .04471 33000.00 .05876 .05810 .05429 .05389 .05168 .04960 .04886 .04416 31500.00 .06517 .06179 .06008 .05770 .05501 .05375 .04836 .04241 30000.00 .07157 .06750 .06522 .06180 .05968 .05343 .04678 .04397 28500.00 .07776 .07472 .07053 .06708 .05966 .05213 .04855 .04552 27000.00 .08687 .08217 .07668 .06743 .05881 .05434 .05106 .04769 25500.00 .09823 .08984 .07752 .06739 .06212 .05740 .05186 .04583 24000.00 .10850 .09123 .07920 .07189 .06384 .05541 .04768 .04203 22500.00 .11105 .09596 .08281 .06991 .05899 .05164 .04653 .04240 21000.00 .11673 .09454 .07788 .06612 .05746 .05223 .04879 .04612 19500.00 .11280 .09139 .07887 .07010 .06361 .05803 .05289 .04848 18000.00 .11580 .09753 .08451 .07450 .06687 .06102 .05612 .05171 16500.00 .13636 .11317 .09701 .08457 .07416 .06563 .05882 .05334 15000.00 .13968 .11620 .09935 .08632 .07628 .06857 .06246 .05738 13500.00 .13538 .11375 .09741 .08536 .07637 .06909 .06288 .05746 A1-10 12000.00 I .12895 .11230 .09743 .08412 .07386 .06627 .06070 .05618 10500.00 .12024 .10166 .09056 .08209 .07430 .06706 .06074 .05527 9000.00 .11530 .09656 .08381 .07653 .07045 .06513 .06019 .05533 7500.00 .10939 .09375 .08119 .07067 .06394 .06027 .05644 .05316 6000.00 .10635 .08992 .07972 .07070 .06184 .05576 .05225 .04963 4500.00 .10185 .08862 .07679 .06820 .06242 .05565 .05011 .04656 3000.00 .09487 .08578 .07516 .06722 .06023 .05522 .05006 .04566 1500.00 .08978 .08258 .07364 .06518 .05937 .05419 .04983 .04544 .00 I .08476 .07899 .07273 .06424 .05759 .05304 .04899 .04556 ·1500.00 .07960 .07429 .07030 .06473 .05704 .05158 .04794 .04456 ·3000.00 .07487 .07054 .06627 .06311 .05791 .05141 .04671 .04372 ·4500.00 .07045 .06671 .06343 .05983 .05704 .05211 .04683 .04271 ·6000.00 .06748 .06325 .06023 .05735 .05454 .05173 .04729 .04301 ·7500.00 .06593 .06029 .05718 .05501 .05214 .05003 .04700 .04328 ·9000.00 .06421 .05818 .05486 .05245 .05041 .04796 .04602 .04287 ••• ISCST3· VERSION 96113 ••• ••• ANGLOGOLD· FREE STATE OPERATIONS 12/10/98 ••• ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 17 "MODELOPTs: CONC RURAL FLAT FLGPOL "'THE ANNUAL ( 8736 HRS) AVERAGE CONCENTRATION VALUES FOR SOURCE GROUP: FSO INCLUDING SOURCE(S): FSOS2A • FSOS2B • FSOS2C • FSOS2D • FSOS3 . FSOS4 • FSOS5A • FSOS5B • FSOS6 • FSOS8A . FSOS8B . FSOS8C • FSOS9 . FSOS10 . FSOS11 • FSOS12 . FSOS13 • FSOS17 • FSOWC FSOWD . FSOWE • FSOWF • FSOWG . FSOWH . FSOWI . FSOWJ . FSOWK . FSOWL . FSOWM • FSOWN ••• NETWORK ID: CARn ; NETWORK TYPE: GRIDCART ••• •• CONC OF RADON IN BO/M3 Y·COORD I X·COORD (METERS) (METERS) I ·5000.00 ·3500.00 ·2000.00 ·500.00 1000.00 2500.00 4000.00 5500.00 7000.00 ... _-------------------------------------------------------------- 39000.00 .20535 .20596 .21458 .22348 .22918 .23894 .25257 .26535 .27053 37500.00 .22489 .22062 .22681 .23761 .24901 .25620 .26948 .28365 .28908 36000.00 .24975 .23692 .24486 .25408 .26623 .27695 .29201 .30515 .31144 34500.00 .27522 .26491 .25798 .27686 .28635 .30090 .31977 .32746 .33904 33000.00 .30094 .29803 .28463 .29512 .31183 .32863 .35210 .35890 .37250 31500.00 .32928 .33572 .32405 .31875 .33940 .36574 .38665 .40219 .41353 30000.00 .35738 .37702 .37511 .36137 .37642 .40000 .43557 .45579 .46760 28500.00 .37782 .40336 .42881 .42877 .42819 .45265 .48914 .52232 .53742 27000.00 .41284 .44369 .47271 .48980 .48863 .53638 .57803 .61355 .62875 25500.00 .48500 .49343 .52708 .56285 .57883 .60822 .69442 .75741 .77360 24000.00 .59962 .61104 .62845 .66949 .70793 .74776 .84919 .95982 1.05248 22500.00 .73508 .78397 .83096 .87146 .94080 1.01703 1.18553 1.38275 1.33900 21000.00 .84943 .94587 1.07389 1.21586 1.38145 1.60561 2.09182 2.20074 1.76691 19500.00 .91322 1.04166 1.21885 1.48548 1.93277 2.79680 4.22766 3.60520 2.64951 18000.00 .96507 1.10485 1.30318 1.61695 2.25761 3.58075 5.12445 4.19386 2.83164 16500.00 1.00856 1.16556 1.39828 1.77214 2.31884 3.28781 4.27780 3.76016 2.95709 15000.00 1.04945 1.23566 1.48697 1.81796 2.27298 2.95105 3.45723 3.55286 3.91679 13500.00 1.09366 1.27194 1.49574 1.75596 2.14880 2.66327 3.32781 4.21653 3.78914 12000.00 1.12479 1.28949 1.44570 1.68164 2.01320 2.47358 3.05984 3.13439 2.67842 10500.00 I 1.10326 1.21946 1.39306 1.63232 1.91062 2.21854 2.48851 2.42311 2.15280 9000.00 I 1.07618 1.18173 1.35101 1.55843 1.76032 1.95880 2.13266 2.05490 1.90102 7500.00 I 1.03005 1.15334 1.29810 1.45210 1.58233 1.76993 1.88797 1.83593 1.77829 6000.00 I .98530 1.09521 1.22047 1.31413 1.44123 1.59073 1.68849 1.66547 1.67130 4500.00 I .94894 1.03688 1.11880 1.21673 1.33608 1.44600 1.51541 1.51385 1.54373 3000.00 I .91159 .98683 1.06366 1.15383 1.25554 1.34715 1.40808 1.43036 1.46840 1500.00 I .87713 .93896 1.01318 1.09633 1.17333 1.25543 1.31207 1.34677 1.40892 .00 I .83077 .89362 .95831 1.03187 1.10206 1.18556 1.26112 1.30616 1.36247 ·1500.00 I .79526 .86159 .92886 1.00008 1.06318 1.13998 1.19753 1.24900 1.27318 ·3000.00 I .78822 .84392 .90355 .95855 1.01723 108148 1.14721 1.17095 1.15967 ·4500.00 I .77244 .81694 .86977 .91019 .96980 1.04115 1.07600 1.08286 1.04438 ·6000.00 I .74735 .78839 .83286 .87412 .93421 .98065 1.00366 .98043 .96391 ·7500.00 I .72001 .75896 .80168 .84301 .66896 .91893 .91464 .91074 .89545 ·9000.00 I .69482 .73948 .77066 .80617 .83679 .84229 .85181 .85183 .84496 ••• ISCST3· VERSION 96113 ••• • •• ANGLOGOLD· FREE STATE OPERATIONS 12110/98 ••• ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 18 "MODELOPTs: CONC RURAL FLAT FLGPOL ••• THE ANNUAL ( 8736 HRS) AVERAGE CONCENTRATION VALUES FOR SOURCE GROUP: FSO INCLUDING SOURCE(S): FSOS2A. FSOS2B • FSOS2C • FSOS2D • FSOS3 • FSOS4 • FSOS5A . FSOS5B • FSOS6 • FSOS8A • FSOS8B . FSOS8C • FSOS9 • FSOS10 . FSOS11 • FSOS12 • FSOS13 • FSOS17 . FSOWC FSOWD . FSOWE • FSOWF . FSOWG • FSOWH • FSOWI • FSOWJ . FSOWK . FSOWL • FSOWM • FSOWN . ••• NETWORK ID: CART1 • NETWORK TYPE: GRIDCART ••• •• CONC OF RADON IN BO/M3 Y·COORD I X·COORD (METERS) (METERS) I 8500.00 10000.00 11500.00 13000.00 14500.00 16000.00 17500.00 19000.00 20500.00 ------------------------------------------------------------------ 39000.00 I .28551 .28950 .29599 .29381 .29302 .28423 .27696 .27621 .26529 37500.00 I .30752 .30985 .31835 .31374 .31161 .30316 .29654 .29368 .28386 36000.00 I .33220 .33316 .34158 .33755 .33296 .32330 .31815 .31565 .30029 34500.00 I .35950 .36024 .36719 .36216 .35794 .34816 .34507 .33294 .31139 33000.00 I .39053 .39413 .40183 .39456 .38846 .38019 .36554 .34695 .32974 31500.00 I .42783 .44076 .44087 .42960 .42553 .40339 .38397 .36908 .34885 30000.00 I .47346 .48960 .49654 .47885 .45263 .43004 .41261 .38852 .36599 28500.00 I .53663 .55498 .55474 .51436 .49183 .45847 .43496 .41753 .38615 27000.00 I .62854 .65811 .60597 .56409 .52803 .49614 .47406 .44039 .40723 25500.00 I .80379 .77624 .69311 .62788 .57080 .53144 .49022 .45075 .42197 24000.00 I 1.18928 .91171 .76940 .69055 .62556 .56700 .52352 .47534 .45031 22500.00 I 1.24562 1.00471 .82428 .72680 .64687 .58386 .54572 .50051 .47737 21000.00 I 1.47072 1.10052 .90532 .77256 .69827 .62674 .59116 .54220 .50528 19500.00 I 1.86663 1.26092 1.01992 .84593 .77052 .69957 .64486 .59213 .54848 18000.00 I 1.92930 1.42923 1.11314 .96108 .85675 .75766 .70037 .64811 .59854 16500.00 I 2.17706 1.50083 1.18566 1.15010 .95224 .83373 .77221 .71734 .64803 15000.00 I 2.42070 1.52813 1.26075 1.15394 1.01079 .89490 .85453 .79446 .71529 A 1-11 13500.00 I 2.31702 1.56678 1.35351 1.30757 1.09593 1.00240 1.00772 .92991 .80836 12000.00 I 2.01635 1.56268 1.41355 1.36756 1.25666 1.23983 1.34858 1.13268 .90957 10500.00 I 1.78946 1.57484 1.46507 1.46819 1.51777 1.77768 2.35470 1.42384 1.02377 9000.00 I 1.69830 1.62102 1.70625 1.76552 1.86719 2.28172 2.90192 1.71429 1.10077 7500.00 I 1.68644 1.71216 1.89807 2.09567 2.54152 3.31429 3.26917 1.85150 1.13760 6000.00 I 1.70863 1.86446 2.17255 2.91243 3.42027 3.80412 3.56183 1.93681 1.15335 4500.00 I 1.63695 1.92967 2.65898 4.24382 3.88960 3.90923 2.67974 1.62148 1.09738 3000.00 I 1.58939 1.90110 2.56841 3.58214 3.12462 2.65545 1.95260 1.32182 .99435 1500.00 I 1.56178 1.80166 2.16781 2.48470 2.25362 1.99553 1.55073 1.10865 .89748 .00 I 1.45762 1.57825 1.80774 1.91292 1.75597 1.59210 1.29727 .98084 .81981 -1500.00 I 1.30592 1.40072 1.51741 1.57365 1.45166 1.32031 1.11702 .87809 .75140 -3000.00 I 1.17429 1.24416 1.32551 1.33581 1.22983 1.13378 .97258 .79078 .69904 -4500.00 I 1.06821 1.11508 1.17655 1.16656 1.06798 .99763 .85636 .71866 .65273 -6000.00 I .98612 1.01229 1.04546 1.03182 .94806 .89155 .76646 .65278 .61022 -7500.00 I .91053 .92953 .94101 .92085 .85385 .80459 .69660 .59778 .56129 -9000.00 I .84339 .84916 85605 .83272 .77830 .73183 .64018 .55059 .51713 ••• ISCST3 - VERSION 96113 ••• ••• ANGLOGOLD - FREE STATE OPERATIONS 12/10/98 _. ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 19 "MODELOPTs: CONC RURAL FLAT FLGPOL ••• THE ANNUAL ( 8736 HRS) AVERAGE CONCENTRATION VALUES FOR SOURCE GROUP: FSO INCLUDING SOURCE(S): FSOS2A, FSOS28 ,FSOS2C ,FSOS2D ,FSOS3 ,FSOS4 ,FSOS5A , FSOS58 ,FSOS6 . FSOS8A • FSOS88 . FSOS8C ,FSOS9 ,FSOS10 ,FSOS11 . FSOS12 ,FSOS13 ,FSOS17 ,FSOWC FSOWD ,FSOWE ,FSOWF ,FSOWG ,FSOWH ,FSOWI • FSOWJ ,FSOWK ,FSOWL . FSOWM • FSOWN , . • - NETWORK ID: CART1 ; NETWORK TYPE: GRIDCART ••• •• CONC OF RADON IN 801M3 Y-COORD I X-COORD (METERS) (METERS) I 22000.00 23500.00 25000.00 26500.00 28000.00 29500.00 31000.00 32500.00 ------------------------------.-----------_._--------------------- 39000.00 .26409 .26409 .25196 .23921 .22682 .21715 .20730 .19798 37500.00 .28011 .27075 .26179 .24718 .23508 .22371 .21200 .20324 36000.00 .28885 .28395 .27218 .25590 .24326 .22809 .21697 .20910 34500.00 .30475 .29805 .28288 .26463 .24673 .23337 .22460 .21570 33000.00 .32184 .31280 .28977 .26951 .25330 .24297 .23320 .22220 31500.00 .33881 .32139 .29750 .27861 .26538 .25064 .23708 .22611 30000.00 .35556 .33455 .30734 .28792 .27063 .25833 .24522 .23201 28500.00 .37142 .34500 .31975 .29777 .27927 .26209 .24820 .23411 27000.00 .38440 .35048 .32300 .30094 .28283 .26778 .25158 .23852 25500.00 .39792 .36314 .33690 .31442 .29620 .27959 .26492 .25344 24000.00 .41442 .37980 .35301 .33124 .31145 .29142 .27721 .26581 22500.00 .44276 .40134 .37052 .34705 .32626 .30979 .29489 .27624 21000.00 .46011 .42340 .39500 .36996 .34516 .32528 .30347 .28285 19500.00 .49500 .45281 .41821 .38908 .36802 .34400 .32006 .29728 18000.00 .53891 .49503 .45927 .42600 .39172 .35996 .32998 .30514 16500.00 .58547 .53563 .49096 .44820 .40807 .36983 .34025 .31692 15000.00 .63626 .57496 .51575 .46329 .41565 .37995 .34914 .32062 13500.00 .70513 .60910 .53337 .46978 .42284 .38239 .34696 .31521 12000.00 .75309 .64244 .54341 .47261 .42098 .37609 .33708 .30936 10500.00 .80490 .64903 .55456 .47670 .41470 .37205 .34167 .31501 9000.00 .81965 .66163 .54784 .48026 .42755 .38280 .34991 .32422 7500.00 .81938 .66229 .56253 .49328 .44007 .39633 .35869 .32736 6000.00 .84135 .67775 .57223 .49930 .44412 .40158 .36643 .33617 4500.00 .83963 .67893 .57760 .50568 .45221 .40903 .37428 .34543 3000.00 .79419 .65322 .55894 .48802 .43485 .39710 .36690 .34046 1500.00 .74260 .62330 .53242 .46910 .42170 .38095 .34922 .32406 .00 I .69224 .60096 .51917 .45336 .40790 .37000 .33962 .31484 -1500.00 I .64786 .56787 .50420 .44707 .39740 .36221 .33322 .30657 -3000.00 I .60974 .53938 .48276 .43405 .39221 .35369 .32514 .30280 -4500.00 I .57487 .51850 .46434 .42149 .38134 .34963 .31934 .29455 -6000.00 I .54767 .49326 .45073 .40742 .37419 .34069 .31533 .29194 -7500.00 I .52121 .46909 .43379 .39834 .36407 .33586 .30840 .28732 -9000.00 I .49279 .45088 .41735 .38679 .35567 .32967 .30441 .28196 "'ISCST3 - VERSION 96113 ••• ••• ANGLOGOLD - FREE STATE OPERATIONS 12/10/98 ••• ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 20 "MODELOPTs: CONC RURAL FLAT FLGPOL ••• THE ANNUAL ( 8736 HRS) AVERAGE CONCENTRATION VALUES FOR SOURCE GROUP: HARMONY'" INCLUDING SOURCE(S); HARS1, HARS2 . HARS3 ,HARS4A ,HARS48 ,HARS5 • HARS6 , HARS7 ,HARS14A. HARS148, HARS15 . HARS16A, HARS168. HARW1 . HARW2 ,HARW3 ,HARW4 ,HARW5 . HARW6 HARW7 • HARW8 ,HARW9 • HARW10 ,HARWU . HARWT • HARWFU ,HARWV. HARWW . HARWX ,HARUHA1 . •- NETWORK ID: CART1 ; NETWORK TYPE: GRIDCART ••• •• CONC OF RADON IN 801M3 Y-COORD I X-COORD (METERS) (METERS) I -5000.00 -3500.00 -2000.00 -500.00 1000.00 2500.00 4000.00 5500.00 7000.00 .----------------------------------------------- •••• _- ____ A_MOO_A. 39000.00 I .13876 .14076 .14119 .14317 .14136 .13727 .13490 .13016 .12721 37500.00 I .14241 .14592 .14712 .14822 .14924 .14620 .14341 .13991 .13481 36000.00 I .14584 .15058 .15312 .15421 .15599 .15497 .15244 .15021 .14438 34500.00 I .14704 .15467 .15940 .16048 .16274 .16351 .16162 .16055 .15612 33000.00 I .15044 .15591 .16462 .16831 .16875 .17234 .17125 .16999 .16919 31500.00 I .15752 .15994 .16591 .17568 .17736 .17887 .18202 .18030 .18033 30000.00 I .16482 .16836 .17048 .17757 .18698 .18746 .19057 .19322 .19041 28500.00 I .17239 .17662 .18088 .18242 .19124 .19851 .19954 .20370 .20481 27000.00 I .18426 .18525 .19004 .19502 .19685 .20585 .21152 .21369 .21981 25500.00 I .19566 .19994 .20057 .20561 .21055 .21468 .22160 .22652 .23198 24000.00 I .21173 .21262 .21802 .21911 .22449 .22838 .23422 .24037 .24518 22500.00 I .23190 .23176 .23230 .23798 .24075 .24707 .25190 .25485 .26188 21000.00 I .25593 .25725 .25644 .25694 .26155 .26554 .27172 .28089 .28040 19500.00 I .28034 .28384 .28817 .28769 .28854 .29137 .29603 .30210 .31033 18000.00 I .30896 .31051 .31350 .32291 .32453 .32784 .33152 .33557 .34425 16500.00 I .33968 .34447 .34795 .35079 .36009 .36630 .37371 .38149 .38766 A1-12 15000.00 I .37231 .37894 .38755 .39498 .39953 .41101 .41557 .42729 .43821 13500.00 I .40180 .41450 .42670 .43666 .44930 .46193 .47542 .48797 .50155 12000.00 I .42235 .43878 .45544 .47364 .49202 .50827 .52889 .55823 .57815 10500.00 .44220 .46174 .48282 .50412 .52494 .54976 .57721 .60740 .64215 9000.00 .45401 .47726 .50324 .53129 .56155 .59338 .62569 .66550 .71181 7500.00 47158 .49740 .52559 .55667 .59183 .63241 .68092 .73573 .79809 6000.00 .48524 .51717 .55090 .58873 .63144 .68042 .73438 .79892 .88294 4500.00 .48693 .52035 .55892 .60086 .64626 .69553 .75673 .83875 .91292 3000.00 .49153 .52387 .55968 .59802 .64473 .69972 .78168 .85261 .93161 1500.00 .49217 .51974 .55701 .60496 .66018 .73331 .79568 .87065 .97261 .00 I .49722 .53713 .57916 .63060 .68317 .73623 .79533 .89110 .99620 -1500.00 .51151 .54705 .59324 .63546 .68584 .74224 .82876 .90890 1.00453 -3000.00 .50523 .54456 .58042 .62454 .67739 .74247 .80690 .88538 1.01306 -4500.00 .50298 .53424 .57278 .62042 .68998 .72101 .79950 .89702 .98833 -6000.00 .49962 .53539 .57784 .61875 .66536 .74046 .81345 .89645 .97050 -7500.00 .51106 .54954 .58242 .62811 .69591 .75960 .81976 .88259 .94974 -9000.00 .52042 .54802 .59275 .64926 .69932 .73906 .76880 .83893 .91098 ••• ISCST3 - VERSION 96113 ••• • •• ANGLOGOLD - FREE STATE OPERATIONS 12/10/98 ~. ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 21 "MODELOPTs: CONC RURAL FLAT FLGPOL ••• THE ANNUAL ( 8736 HRS) AVERAGE CONCENTRATION VALUES FOR SOURCE GROUP: HARMONY'" INCLUDING SOURCE(S): HARS1 , HARS2 , HARS3 ,HARS4A ,HARS4B ,HARS5 , HARS6 HARS7 ,HARS14A, HARS14B, HARS15 ,HARS16A, HARS16B, HARW1 , HARW2 , HARW3 , HARW4 , HARW5 , HARW6 HARVV7 , HARW8 , HARW9 ,HARW10 ,HARWU , HARWT , HARWFU , HARWV , HARWW ,HARWX ,HARUHA1, m NETWORK ID: CART1 , NETWORK TYPE: GRIDCART ••• ~ CONC OF RADON IN BQ/M3 Y-COORD I X-COORD (METERS) (METERS) I 8500.00 10000.00 11500.00 13000.00 14500.00 16000.00 17500.00 19000.00 20500.00 ------------------------------------------------------------------ 39000.00 .13100 .14207 .14982 .15792 .16505 .16708 .17464 .18350 .19135 37500.00 .13553 .14513 .15471 .16317 .17134 .17502 .18197 .19194 .19997 36000.00 .14261 .14837 .16002 .16857 .17806 .18355 .19006 .20111 .20960 34500.00 .15145 .15405 .16436 .17493 .18507 .19215 .19949 .21081 .22036 33000.00 .16255 .16253 .16908 .18174 .19260 .20120 .21059 .22098 .23222 31500.00 .17685 .17295 .17671 .18787 .20145 .21069 .22273 .23227 .24509 30000.00 .19150 .18688 .18756 .19485 .21036 .22099 .23532 .24583 .25905 28500.00 .20368 .20403 .20183 .20442 .21964 .23360 .24849 .26204 .27473 27000.00 .21890 .22021 .21987 .21840 .23051 .24611 .26255 .27953 .29274 25500.00 .23595 .23679 .23835 .23842 .24415 .26106 .28028 .29892 .31449 24000.00 .25151 .25552 .25991 .25947 .26537 .27681 .29836 .32122 .34008 22500.00 .27050 .27539 .28261 .28604 .29183 .29725 .32084 .34840 .36842 21000.00 .29152 .30091 .30619 .31704 .32497 .32330 .34879 .37691 .40361 19500.00 .31101 .32789 .33663 .34813 .36564 .36609 .38185 .41204 .44571 18000.00 .34705 .34986 .37524 .38711 .41044 .42125 .42841 .45216 .49700 16500.00 .39912 .40162 .40821 .43733 .45300 .49318 .49891 .51405 .55438 15000.00 .45205 .46759 .48026 .50741 .52618 .55852 .57551 .60007 .64631 13500.00 .51511 .53843 .56626 .60916 .64064 .65215 .68284 .70584 .76126 12000.00 .60523 .62868 .66497 .75127 .80416 .81334 .84866 .89425 .98090 10500.00 .67625 .73478 .83058 1.03400 .98887 1.06429 1.13750 1.30508 1.53493 9000.00 .78241 .86365 1.03786 1.04718 1.10942 1.24092 1.44273 1.84447 2.98078 7500.00 .87777 .99414 1.13692 1.14327 1.26146 1.39430 1.70794 2.34527 3.54021 6000.00 .96599 1.06295 1.20756 1.30712 1.45483 1.60442 1.94380 2.44262 3.17506 4500.00 1.00931 1.14654 1.29888 1.44852 1.60605 1.84686 2.13443 2.53207 3.20541 3000.00 1.04652 1.18812 1.34726 1.52172 1.78943 1.93645 2.32557 2.99650 4.51190 1500.00 1.08867 1.22009 1.42640 1.67403 1.82918 2.09060 2.42403 3.23853 4.76314 .00 I 1.12102 1.29784 1.47629 1.67339 1.78239 2.08915 2.45283 3.06228 3.83059 -1500.00 I 1.14481 1.28944 1.46952 1.63682 1.81122 2.09744 2.37730 2.87566 3.27507 -3000.00 I 1.11602 1.25770 1.40073 1.58924 1.78629 2.05028 2.33783 2.72014 3.15069 -4500.00 I 1.08908 1.20765 1.36533 1.55774 1.70061 1.93983 2.28152 2.79256 3.51176 -6000.00 I 1.06416 1.18816 1.31960 1.46255 1.57884 1.82545 2.15373 2.68789 3.92383 -7500.00 I 1.03931 1.14085 1.26222 1.37852 1.53613 1.77581 2.07029 2.52906 3.15679 -9000.00 I .99980 1.09754 1.21422 1.35557 1.49912 1.68866 1.92237 2.19118 2.45963 ••• ISCST3 - VERSION 96113 ••• • •• ANGLOGOLD - FREE STATE OPERATIONS 12/10/98 ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 22 "MODELOPTs: CONC RURAL FLAT FLGPOL "'THE ANNUAL ( 8736 HRS) AVERAGE CONCENTRATION VALUES FOR SOURCE GROUP: HARMONY'" INCLUDING SOURCE(S): HARS1, HARS2 ,HARS3 ,HARS4A ,HARS4B ,HARS5 ,HARS6 , HARS7 ,HARS14A, HARS14B, HARS15 ,HARS16A, HARS16B, HARW1 ,HARW2 ,HARW3 ,HARW4 ,HARW5 ,HARW6 HARVV7 ,HARW8 ,HARW9 ,HARW10, HARWU ,HARWT ,HARWFU ,HARWV, HARWW ,HARWX ,HARUHA1, ••• NETWORK ID: CART1 , NETWORK TYPE: GRIDCART'" ~ CONC OF RADON IN BQ/M3 Y-COORD I X-COORD (METERS) (METERS) I 22000.00 23500.00 25000.00 26500.00 28000.00 29500.00 31000.00 32500.00 ------------------------------------------------------------------ 39000.00 .20068 .20145 .19422 .19594 .20014 .20404 .20427 .20399 37500.00 .21014 .21019 .20357 .20644 .21165 .21425 .21379 .21313 36000.00 .22024 .22005 .21384 .21839 .22381 .22539 .22372 .22320 34500.00 .23096 .23158 .22508 .23163 .23727 .23717 .23431 .23412 33000.00 .24278 .24449 .23780 .24594 .25235 .24946 .24618 .24575 31500.00 .25683 .25853 .25195 .26296 .26760 .26285 .25965 .25904 30000.00 .27333 .27380 .26801 .28219 .28369 .27719 .27558 .27324 28500.00 .29199 .29009 .28858 .30258 .30144 .29373 .29372 .28524 27000.00 .31209 .30910 .31244 .32519 .32155 .31398 .30858 .30099 25500.00 .33342 .33250 .33912 .35199 .34382 .33236 .32936 .31713 24000.00 .36014 .36047 .37070 .38037 .36383 .35698 .35130 .33703 22500.00 .39045 .39324 .40816 .40600 .39258 .38589 .37277 .35879 21000.00 .42673 .43411 .44467 .44294 .42786 .41477 .40359 .38512 19500.00 .47382 .47497 .49400 .48601 .46358 .45592 .43588 .40109 18000.00 .52275 .53379 .54965 .53408 .51106 .49839 .45972 .42172 A1-13 16500.00 I .59222 .61076 .61278 .60189 .57415 .53542 .48857 .45070 15000.00 I .69219 .71101 .71891 .69426 .63427 .57270 .52972 .48511 13500.00 I .85047 .90063 .92143 .80197 .70585 .62812 .56310 .50740 12000.00 I 1.12571 1.20122 1.09786 .89614 .77256 .68828 .61452 .54812 10500.00 I 1.86628 1.69309 1.22207 .99953 .86099 .75675 .66241 .59153 9000.00 I 3.57995 2.05165 1.41963 1.15146 .97169 .83578 .72535 .64133 7500.00 I 3.05067 2.10186 1.59128 1.27941 1.07236 .90628 .78750 .67633 6000.00 I 3.53234 2.70296 1.86906 1.43173 1.18482 .99897 .82937 .71949 4500.00 I 3.84311 3.50780 2.13520 1.66034 1.35527 1.10061 .89488 .74645 3000.00 I 4.26395 3.04433 2.48739 2.21434 1.74270 1.20350 .95418 .78470 1500.00 I 4.08377 2.87726 3.02424 3.03979 1.92433 1.30185 1.00845 .81819 00 I 3.43856 3.06469 2.97421 2.56615 1.84752 1.29641 .98400 .78746 -1500.00 I 3.26179 3.24388 3.45012 3.05369 1.77406 1.27231 .95581 .77776 -3000.00 I 3.51284 4.41236 4.88643 3.44382 1.79665 1.25910 .97723 .79824 -4500.00 I 4.44785 4.61649 4.08231 2.51033 1.64435 1.19645 .95116 .77964 -6000.00 I 4.70409 3.65604 2.84026 1.97656 1.44773 1.10676 .91117 .75750 -7500.00 I 3.11204 2.74726 2.14267 1.61766 1.26030 1.01601 .84702 .72482 -9000.00 I 2.39120 2.17948 1.76541 1.36396 1.12780 .93573 .78986 .88883 ••• ISCST3 - VERSION 96113 ••• ••• ANGLOGOLD - FREE STATE OPERATIONS 12/10/98 ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 23 ··MODELOPTs: CONC RURAL FLAT FLGPOL ••• THE ANNUAL ( 8736 HRS) AVERAGE CONCENTRATION VALUES FOR SOURCE GROUP: LOR INCLUDING SOURCE(S): LORS1 , LORS2 ,LORS3 ,LORW1 , LORW2 , LORU2 ••• NETWORK ID: CART1 , NETWORK TYPE: GRIDCART ••• - CONC OF RADON IN 60/M3 Y-COORD I X-COORD (METERS) (METERS) I -5000.00 -3500.00 -2000.00 -500.00 1000.00 2500.00 4000.00 5500.00 7000.00 -------------------------------_---------------------------------- 39000.00 .12107 .12462 .12034 .14929 .17375 .18674 .16822 .13396 .10940 37500.00 .14967 .17644 .19071 .21226 .25080 .28245 .21043 .15123 .11490 36000.00 .21994 .24216 .29393 .38325 .51422 .49343 .25805 .16664 .12291 34500.00 .29735 .39795 .53729 .84395 .95593 .53403 .26588 .16952 .12651 33000.00 .31393 .44952 .78142 1.58115 1.23453 .49955 .27397 .17807 .13467 31500.00 .31521 .46811 .71759 1.25937 .91714 .40613 .25329 .17408 .13176 30000.00 .32690 .42378 .59311 .77013 .53691 .32524 .21207 .15865 .12169 28500.00 .29579 .36007 .45472 .51427 .37567 .25036 .18841 .14591 .11155 27000.00 .25381 .30034 .36364 .37782 .27967 .19766 .17226 .13040 .10992 25500.00 .22105 .26795 .28970 .29660 .22147 .16976 .14571 .12136 .10185 24000.00 .19947 .23066 .23841 .24327 .18303 .14735 .12331 .11103 .09351 22500.00 .18610 .19845 .20344 .20529 .15590 .12640 .10853 .09855 .08893 21000.00 .16766 .17039 .17719 .17676 .13576 .10959 .09842 .08896 .08050 19500.00 .14966 .15021 .15625 .15459 .12023 .09691 .09071 .08176 .07333 18000.00 .13207 .13508 .13957 .13693 .10794 .08689 .08275 .07447 .06748 16500,00 .11838 .12239 .12630 .12261 .09802 .07883 .07492 .06897 .06401 15000.00 .10820 .11137 .11549 .11074 .08980 .07227 .06824 .06506 .06039 13500.00 .10046 .10203 .10634 .10075 .08285 .06682 .06275 .06127 .05645 12000.00 .09359 .09421 .09841 .09227 .07689 .06219 .05801 .05706 .05309 10500.00 .08700 .08763 .09139 .08498 .07171 .05817 .05378 .05288 .05048 9000.00 .08085 .08203 .08510 .07865 .06715 .05464 .05002 .04924 .04822 7500.00 .07535 .07721 .07945 .07311 .06309 .05152 .04674 .04622 .04585 6000.00 .07056 .07300 .07435 .06823 .05947 .04875 .04391 .04363 .04327 4500.00 .06641 .06925 .06975 .06390 .05621 .04629 .04145 .04128 .04070 3000.00 .06283 .06585 .06561 .06005 .05328 .04410 .03931 .03908 .03838 1500.00 .05973 .06271 .06188 .05662 .05063 .04214 .03740 .03703 .03640 .00 I .05702 .05977 .05851 .05352 .04821 .04037 .03569 .03513 .03470 -1500.00 I .05464 .05701 .05542 .05072 .04600 .03875 .03412 .03340 .03318 -3000.00 I .05250 .05441 .05260 .04817 .04396 .03727 .03269 .03183 .03178 -4500.00 I .05055 .05196 .05002 .04584 .04208 .03590 .03138 .03041 .03044 -6000.00 I .04875 .04968 .04766 .04371 .04034 .03464 .03017 .02913 .02916 -7500.00 I .04704 .04755 .04547 .04176 .03874 .03347 .02907 .02797 .02796 -9000.00 I .04540 .04556 .04347 .03997 .03725 .03238 .02805 .02690 .02684 ••• ISCST3 - VERSION 96113 ••• • •• ANGLOGOLD - FREE STATE OPERATIONS 12/10/98 ••• ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 24 ··MODELOPTs: CONC RURAL FLAT FLGPOL ••• THE ANNUAL ( 8736 HRS) AVERAGE CONCENTRATION VALUES FOR SOURCE GROUP: LOR INCLUDING SOURCE(S) LORS1 , LORS2 , LORS3 , LORW1 , LORW2 , LORU2 -- NETWORK ID: CART1 ; NETWORK TYPE: GRIDCART ••• - CONC OF RADON IN 60/M3 Y-COORD I X-COORD (METERS) (METERS) I 8500.00 10000.00 11500.00 13000.00 14500.00 16000.00 17500.00 19000.00 20500.00 ------------------------------------------._---------------------- 39000.00 I .08483 .07265 .06099 .05227 .04662 .04166 .03698 .03346 .03072 37500.00 I .09235 .07470 .06101 .05150 .04559 .04123 .03734 .03448 .03235 36000.00 I .09442 .07879 .06692 .05713 .05044 .04532 .04084 .03698 .03376 34500.00 I .10175 .08435 .07149 .06207 .05483 .04903 .04426 .04029 .03697 33000.00 I .10700 .08737 .07472 .06585 .05876 .05255 .04699 .04229 .03852 31500.00 I .10370 .08724 .07547 .06579 .05710 .05078 .04618 .04271 .03986 30000.00 I .09858 .08021 ,07014 .06138 .05456 .04948 .04463 .04079 .03768 28500.00 I .09308 .08052 .06711 .05850 .05249 .04704 .04291 .03993 .03685 27000.00 I .08598 .07397 .06590 .05781 .05148 .04658 .04248 .03838 .03510 25500.00 I .08632 .07028 .06114 .05534 .04993 .04489 .04174 .03869 .03578 24000.00 I .08226 .07016 .05956 .05213 .04751 .04387 .03964 .03702 .03495 22500.00 I .07737 .06855 .05891 .05174 .04552 .04167 .Q3895 .03566 .03318 21000.00 I .07353 .06536 .05786 .05078 .04568 .04054 .03712 .03502 .03232 19500.00 I .06855 .06287 .05649 .04975 .04466 .04083 .03670 .03347 .03180 18000.00 I .06297 .06015 .05443 .04938 .04365 .03986 .03683 .03359 .03054 16500.00 I .05847 .05506 .05313 .04809 .04332 .03887 .03595 .03349 .03096 15000.00 I .05418 .05158 .05010 .04685 .04309 .03839 .03503 .03268 .Q3065 13500.00 I .05173 .04863 .04585 .04571 .04194 .03874 .03447 .03190 .02993 A1-14 12000.00 I .04970 ,04537 .04359 ,04244 .04109 .03803 .03485 .03126 .02930 10500.00 I .04740 .04334 .04152 .03925 .03962 .03718 .03469 .03154 .02859 9000,00 I .04510 .04189 .03906 .03766 .03663 .03640 .03404 .03169 .02879 7500.00 I .04301 .04034 .03733 .03612 .03430 .03461 .03334 .03141 .02899 6000.00 I .04118 .03874 .03616 .03426 .03310 .03218 .03240 .03075 .02902 4500.00 I .03956 .03728 .03503 .03284 .03189 .03046 .03059 .03012 .02859 3000.00 I .03800 .03594 .03380 .03183 .03047 .02951 .02869 .02895 .02802 1500.00 I .03636 .03470 .03264 .03094 .02932 .02851 .02738 .02735 .02728 .00 I .03465 .03352 .03163 .02999 .02845 .02738 .02659 .02588 .02603 -1500.00 I .03295 .03238 .03072 .02901 .02770 .02645 .02574 .02486 .02472 -3000.00 I .03137 .03121 .02985 .02812 .02695 .02572 .02482 .02418 .02357 -4500.00 I .02997 .03000 .02900 .02737 .02614 .02508 .02406 .02344 .02275 -6000.00 I .02875 .02877 .02816 .02671 .02535 .02445 .02345 .02267 02216 -7500.00 I .02766 .02756 .02729 .02609 .02466 .02380 .02291 .02203 .02151 -9000.00 I .02666 .02644 .02638 .02548 .02407 .02312 .02238 .02153 .02084 ···ISCST3 - VERSION 96113 •••••• ANGLOGOLD - FREE STATE OPERATIONS 12110/98 ••• ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 25 ··MODELOPTs: CONC RURAL FLAT FLGPOL ·"THE ANNUAL ( 8736 HRS) AVERAGE CONCENTRATION VALUES FOR SOURCE GROUP: LOR INCLUDING SOURCE(S): LORS1, LORS2 ,LORS3 ,LORW1 ,LORW2 ,LORU2 ••• NETWORK ID: CART1 ; NETWORK TYPE: GRIDCART ••• - CONC OF RADON IN 801M3 Y-COORD I X-COORD (METERS) (METERS) I 22000.00 23500,00 25000.00 26500.00 28000.00 29500.00 31000.00 32500.00 39000.00 I .02834 .02644 .02496 .02368 .02247 .02130 .02018 .01913 37500.00 I .03044 .02854 .02669 .02497 .02342 .02205 .02083 .01974 36000.00 I .03110 .02888 .02697 .02532 .02387 .02260 .02147 .02047 34500.00 I .03415 .03174 .02964 .02779 .02616 .02469 .02338 .02219 33000.00 .03553 .03307 .03096 .02910 .02742 .02588 .02449 .02321 31500.00 .03727 .03475 .03229 .03000 .02796 .02620 .02469 .02340 30000.00 .03506 .03285 .03105 .D2955 .02821 .02692 .02564 .02437 28500.00 .03384 .03142 .02943 .02770 .02617 .02484 .02372 .02279 27000.00 .03284 .03098 .02902 .02726 .02575 .02442 .02320 .02206 25500.00 .03274 .03015 .02815 .02659 .02510 .02370 .02255 .02159 24000.00 .03301 .03088 .02855 .02652 .02484 .02351 02229 .02107 22500.00 .03151 .02998 .02865 .02707 .02528 .02367 .02228 .02114 21000.00 .03016 .02868 .02736 .02620 .02521 .02401 .02265 .02136 19500.00 .02954 .02761 .02630 .02522 .02415 .02326 .02246 .02151 18000.00 .02904 .02724 .02546 .02423 .02337 .02246 .02160 .02089 16500.00 .02816 .02667 .02527 .02368 .02245 .02168 .02100 .02022 15000.00 I .02869 .02620 .02467 .02352 .02216 .02097 .02018 .01964 13500.00 I .02822 .02670 .02452 .02300 .02195 .02082 .01972 .01889 12000.00 I .02758 .02613 .02495 .02306 .02158 .D2058 .D1958 .01864 10500.00 I .02706 .02556 .02431 .02338 .02176 .02036 .01939 .01847 9000.00 I .02635 .02516 .02381 .02272 .02196 .02059 .01928 .01836 7500.00 I .02646 .02445 .02347 .02227 .02131 .02069 .01953 .01833 6000.00 I .02665 .02446 .02282 .02197 .02091 .02006 .01954 .01857 4500.00 I .02679 .02466 .02272 .02140 .02064 .01971 .01896 .01850 3000.00 I .02669 .02476 .02294 .02121 .02015 .01945 .01864 .01796 1500.00 I .02617 .02491 .02298 .02143 .01991 .01903 .01838 .01767 .00 I .02565 .02459 .02320 .02147 .02008 .01876 .01801 .01742 -1500.00 I .02475 .02412 .02316 .02161 .02015 .01887 .01775 .01709 -3000.00 I .02361 .02353 .02275 .02179 .02020 .01899 .01779 .01685 -4500.00 I .02255 .02256 .02232 .02153 .02045 .01898 .01793 .01683 -6000.00 I .02163 .02158 .02160 .02115 .02041 .01918 .01792 .01697 -7500.00 I .02097 .02073 .02067 .02067 .02009 .01932 .01803 .01698 -9000.00 I .02044 .01998 .01986 .01987 .01973 .01912 .01825 .01701 ···ISCST3 - VERSION 96113 •••••• ANGLOGOLD - FREE STATE OPERATIONS 12110/98 _. ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 26 ··MODELOPTs: CONC RURAL FLAT FLGPOL ••• THE ANNUAL ( 8736 HRS) AVERAGE CONCENTRATION VALUES FOR SOURCE GROUP: KAD INCLUDING SOURCE(S): KADS1, KADWA ,KADW8 ,KADWP ,KADWO ,KADWL3 ,KADUST1 , KADUST2,KADUFR7,KADUL03, -- NETWORK ID: CART1 ; NETWORK TYPE: GRIDCART ••• - CONC OF RADON IN 801M3 Y-COORD I X-COORD (METERS) (METERS) I -5000.00 -3500.00 -2000.00 -500.00 1000.00 2500.00 4000.00 5500.00 7000.00 39000,00 .04705 .04948 .04857 .04677 .05440 .05982 .06822 .06906 .07351 37500.00 .05257 ,05486 .05702 .05338 .06011 .06884 .08116 .08332 .08595 36000.00 .05662 .06193 .06473 .06913 .06752 .08277 .09803 .10131 .09876 34500.00 .06910 .07045 .07549 .08259 .08428 .10173 .11929 .12840 .11907 33000.00 .10472 .09395 .09265 .09771 .11268 .12619 .15935 .16616 .13633 31500.00 .12812 .15618 .15150 .14076 .15520 .18249 .23326 .21325 .16692 30000.00 .14672 .17582 .21499 .27390 .32744 .33765 .39094 .32727 .19736 28500.00 .14876 .17590 .21879 .32134 .58902 .72001 1,23522 .47686 .23824 27000.00 .16094 .20888 .26541 .36332 .51048 .71465 .91894 .41633 .22331 25500.00 .17026 ,21319 .28381 .35127 .46896 .55940 .59369 .33492 .20801 24000.00 .17676 .22187 .26042 .32561 .40987 .56505 .43360 .27214 .19405 22500.00 .18648 .21166 .25645 .30206 .36475 .40162 .32095 .21563 .16690 21000.00 .18561 .20463 .23329 .26674 .32099 .31307 .24562 .17913 .15086 19500.00 .17585 .20094 .21860 ,24405 .27090 .26011 .20846 .15728 .13425 18000.00 .16775 .17853 .20532 .22918 .24038 .22643 .18163 .14060 .12836 16500.00 I .15599 .17294 .18916 .20687 .21698 .20743 .16737 .13670 .12404 15000.00 I .~4218 ,16356 .17662 .18668 .20018 .18845 .15544 .13593 .12889 13500.00 I .14005 .15242 .16461 ,16916 .18170 .17582 .15151 .13541 .12940 12000.00 I .13518 .14275 .15204 .15846 .16729 .15972 .13535 .12448 .13100 10500.00 I .12422 .13226 .13563 .14534 .15251 .14675 .12703 .12013 .12661 A1-15 9000.00 .11934 .12579 .12846 .13833 .14417 .13891 .12093 .11535 .12279 7500.00 .11355 .11741 .12130 .12987 .13551 .13065 .11413 .11320 .12420 6000.00 .10967 .11280 .11825 .12489 .13094 .12884 .11728 .11561 .12068 4500.00 .10382 .10673 .11481 .12276 .12815 .12407 .11122 .11503 .12353 3000.00 .10175 .10524 .11104 .11707 .12151 .12126 .11356 .11624 .12188 1500.00 .09631 .10185 .10786 .11484 .12013 .11653 .11259 .11160 .11383 .00 I .09385 .09937 .10570 .11168 .11294 .11610 .10675 .10619 .11115 -1500.00 .09161 .09713 .10059 .10669 .11350 .10759 .10407 .10186 .10105 -3000.00 .08892 .09158 .09892 .10695 .10408 .10663 .09787 .09399 .09229 -4500.00 .08533 .09184 .09726 .09926 .10414 .09852 .09137 .08592 .08854 -6000.00 .08615 .08846 .09196 .09971 .09551 .09227 .08527 .08288 .08216 ·7500.00 .08214 .08517 .09205 .09167 .06976 .08680 .08067 .07894 .08071 -9000.00 .08003 .08453 .08493 .08674 .08476 .08135 .07896 .07413 .07789 ••• ISCST3 - VERSION 96113 ••• ••• ANGLOGOLD - FREE STATE OPERATIONS 12/10/98 _. ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 27 "MODELOPTs: CONe RURAL FLAT FLGPOL '''THE ANNUAL ( 8736 HRS) AVERAGE CONCENTRATION VALUES FOR SOURCE GROUP: KAD INCLUDING SOURCE(S): KADS1 , KADWA , KADW8 , KADWP , KADWO ,KADWL3 ,KADUST1 , KADUST2,KADUFR7,KADUL03, -- NETWORK ID: CART1 , NETWORK TYPE: GRIDCART ••• - CONC OF RADON IN 801M3 Y-COORD I X-COORD (METERS) (METERS) I 8500.00 10000.00 11500.00 13000.00 14500.00 16000.00 17500.00 19000.00 20500.00 -----_._--------._-_ .... --._---------------------.--- .. ----------- 39000.00 .07078 .06727 .06625 .05930 .05636 .05123 .04947 .04465 .04173 37500.00 .08051 .07755 .06739 .06428 .05883 .05416 .05014 .04456 .04176 36000.00 .09411 .08022 .07530 .06707 .06211 .05317 .05015 .04455 .04282 34500.00 .10038 .09364 .07929 .06837 .06149 .05466 .05118 .04523 .04403 33000.00 .11911 .09528 .08203 .07092 .06148 .05609 .05467 .04830 .04618 31500.00 .12973 .10327 .08557 .07456 .06570 .05744 .05403 .04868 .04761 30000.00 .13374 .10571 .08810 .07532 .06691 .05966 .05702 .05272 .05204 28500.00 .16075 .12266 .10118 .08625 .07728 .06813 .06353 .05914 .05762 27000.00 .15153 .11729 .10191 .08958 .08125 .07217 .06673 .06302 .06071 25500.00 .13958 .11418 .09704 .08171 .07509 .07033 .06732 .06609 .06281 24000.00 .14280 .10793 .09365 .08463 .07881 .07224 .06593 .06496 .06168 22500.00 .13471 .10726 .08891 .08056 .07665 .07293 .06947 .06940 .06417 21000.00 .12631 .10557 .09034 .07968 .07155 .07196 .07164 .07113 .06746 19500.00 .12219 .10471 .08922 .08058 .07597 .07325 .07332 .07426 .07159 18000.00 .11215 .10592 .09235 .08162 .07853 .08142 .08178 .07880 .07548 16500.00 .10801 .10241 .09683 .08756 .08308 .08830 .09248 .09028 .08405 15000.00 .11586 .10442 .10047 .09582 .09032 .10000 .10811 .10692 .09325 13500.00 .12251 .12467 .11848 .10997 .10849 .12576 .14487 .12016 .09979 12000.00 .13494 .13319 .13799 .15347 .15650 .22668 .19037 .14389 .10901 10500.00 .13119 .13813 .16381 .18939 .28289 .57804 .24550 .16126 .11581 9000.00 .12946 .14553 .17668 .24430 .34188 .43662 .30540 .16406 .11176 7500.00 .13746 .15224 .18831 .22353 .35590 .46347 .27895 .15792 .11306 6000.00 .13488 .16425 .18188 .22613 .28497 .30667 .20142 .14527 .10201 4500.00 .14414 .15046 .17138 .20459 .22930 .22836 .15477 .12503 .10044 3000.00 .13150 .14819 .15690 .17162 .19386 .18839 .12781 .10659 .09466 1500.00 .12827 .13460 .14367 .15105 .16191 .15925 .10909 .09875 .08610 .00 I .11402 .11978 .13261 .13870 .14257 .13709 .09528 .09228 .07608 -1500.00 I .10508 .11491 .11907 .12359 .12681 .12033 .08495 .08242 .07140 -3000.00 I .09660 .10874 .11084 .10995 .11445 .10710 .07717 .07327 .06849 -4500.00 I .09332 .09893 .10291 .10108 .10462 .09652 .07113 .06628 .06574 -6000.00 I .08966 .09220 .09462 .09415 .09690 .08799 .06616 .06110 .06204 -7500.00 I .08280 .08534 .08647 .08799 .09040 .08097 .06206 .05702 .05706 -9000.00 I .07913 .07957 .08051 .08280 .08458 .07516 .05864 .05357 .05245 ••• IseST3 - VERSION 96113 ••• ••• ANGLOGOLD - FREE STATE OPERATIONS 12/10/98 ••• ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 28 "MODELOPTs: CONC RURAL FLAT FLGPOL '''THE ANNUAL ( 8736 HRS) AVERAGE CONCENTRATION VALUES FOR SOURCE GROUP: KAD INCLUDING SOURCE(S): KADS1 , KADWA , KADW8 , KADWP , KADWO , KADWL3 , KADUST1 , KADUST2,KADUFR7,KADUL03, ••• NETWORK ID: CART1 ; NETWORK TYPE: GRIDCART ••• •• eONC OF RADON IN 801M3 Y-COORD I X-COORD (METERS) (METERS) I 22000.00 23500.00 25000.00 26500.00 28000.00 29500.00 31000.00 32500.00 --------------------------- __ ._------------------------------_._-- 39000.00 I .04026 .03789 .03423 .03252 .03123 .03002 .02909 .02778 37500.00 .04003 .03804 .03582 .03368 .03159 .03005 .02920 .02781 36000.00 .04206 .03859 .03563 .03362 .03228 .03159 .03081 .03025 34500.00 .04317 .03983 .03729 .03585 .03491 .03430 .03289 .03143 33000.00 .04453 .04176 .03925 .03769 .03615 .03402 .03253 .03068 31500.00 .04485 .04163 .03889 .03739 .03639 .03533 .03390 .03294 30000.00 .04876 .04577 .04426 .04286 .04081 .03921 .03728 .03581 28500.00 .05324 .04880 .04681 .04449 .04278 .04023 .03857 .03752 27000.00 .05667 .05323 .05092 .04848 .04599 .04381 .04246 .04036 25500.00 .05754 .05513 .05176 .04988 .04722 .04612 .04394 .04095 24000.00 .05761 .05603 .05461 .05178 .05027 .04701 .04330 .04114 22500.00 .06037 .05699 .05483 .05315 .04988 .04682 .04491 .04043 21000.00 .06474 .06218 .05826 .05310 .04911 .04655 .04113 .03914 19500.00 .06833 .06612 .06063 .05627 .05237 .04533 .04155 .03722 18000.00 I .07429 .06682 .06141 .05718 .05054 .04503 .04076 .03773 16500.00 I .07519 .06900 .06423 .05331 .04732 .04408 .04174 .03750 15000.00 I .08041 .06909 .05762 .05366 .04872 .04304 .03963 .03753 13500.00 I .08477 .06829 .06081 .05289 .04628 .04307 .04040 .03665 12000.00 I .08544 .06855 .05704 .05161 .04658 .04373 .04192 .03981 10500.00 I .08766 .07488 .06727 .05788 .04976 .04423 .04021 .03697 9000.00 I .08699 .07282 .06489 .05850 .05169 .04564 .04137 .03850 A1-16 7500.00 I .08926 .07450 .06494 .05712 .05162 .04657 .04215 .03877 6000.00 I .08437 .06845 .06018 .05442 .05030 .04651 .04133 .03690 4500.00 I .07851 .06770 .05757 .05231 .04726 .04281 .04027 .03778 3000.00 I .07684 .06563 .05619 .05050 .04519 .04233 .03939 .03630 1500.00 I .07549 .06317 .05659 .04879 .04447 .04068 .03766 .03553 .001 .07376 .06265 .05418 .04967 .04370 .03999 .03676 .03452 -1500.00 I .06669 .06249 .05326 .04761 .04421 .03981 .03642 .03371 -3000.00 I .06020 .06006 .05392 .04647 .04253 .03985 .03660 .03357 -4500.00 I .05743 .05491 .05347 .04697 .04133 .03647 .03629 .03367 -6000.00 I .05491 .05029 .05067 .04758 .04150 .03736 .03517 .03333 -7500.00 I .05286 .04833 .04688 .04634 .04250 .03737 .03419 .03242 -9000.00 I .05106 .04650 04344 .04388 .04246 .03608 .03406 .03156 -" ISCST3 - VERSION 96113 '" '" ANGLOGOLD - FREE STATE OPERATIONS 12/10/98 ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 29 "MODELOPTs: CONC RURAL FLAT FLGPOL "'THE ANNUAL ( 8736 HRS) AVERAGE CONCENTRATION VALUES FOR SOURCE GROUP: FREE INCLUDING SOURCE(S): FSOS2A ,FSOS2B ,FSOS2C ,FSOS2D , FSOS3 , FSOS4 ,FSOS5A , FSOS5B , FSOS6 ,FSOS8A ,FSOS8B ,FSOS8C ,FSOS9 ,FSOS10 ,FSOS11 ,FSOS12 ,FSOS13 ,FSOS17 ,FSOWC FSOWD ,FSOWE , FSOWF , FSOWG , FSOWH ,FSOWI , FSOWJ , FSOWK , FSOWL , FSOWM , FSOWN , . , .. NETWORK ID: CART1 ; NETWORK TYPE: GRIDCART ,,' .. CONC OF RADON IN BO/M3 Y-COORD I X-COORD (METERS) (METERS) I -5000.00 -3500.00 -2000.00 -500.00 1000.00 2500.00 4000.00 5500.00 7000.00 - - - - - -~- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 39000.00 .54006 .54926 .55513 .59380 .63044 .65201 .65111 .62845 .61326 37500.00 .59941 .62769 .65300 .68444 .74310 .78740 .73428 .68918 .65879 36000.00 .70244 .72367 .78916 .89495 1.04009 1.04541 .83480 .75596 .71320 34500.00 .81997 .92091 1.06477 1.39966 1.52750 1.13976 .90626 .82218 .77833 33000.00 .90448 1.03151 1.35934 2.18038 1.86748 1.16883 1.00127 .91549 .85269 31500.00 .96804 1.15836 1.39648 1.93407 1.63110 1.17825 1.10326 1.01898 .93735 30000.00 1.03761 1.18747 1.39664 1.62468 1.47220 1.29836 1.28042 1.19009 1.03008 28500.00 1.04277 1.16284 1.33159 1.49514 1.63064 1.67188 2.16659 1.40767 1.15417 27000.00 1.07033 1.19431 1.34587 1.48147 1.53150 1.70813 1.93918 1.43916 1.25203 25500.00 1.14173 1.24466 1.36876 1.48105 1.54423 1.61655 1.71960 1.51028 1.39269 24000.00 1.26791 1.35964 1.43080 1.54163 1.60636 1.76829 1.71853 1.66119 1.67000 22500.00 1.42358 1.51459 1.61927 1.71960 1.80761 1.89783 1.96808 2.05193 1.95670 21000.00 1.55616 1.67898 1.84504 2.02578 2.22002 2.42452 2.84752 2.89278 2.41957 19500.00 1.62718 1.79261 2.00391 2.30183 2.75030 3.59241 4.98378 4.32885 3.37086 18000.00 1.68586 1.85077 2.09019 2.44409 3.08085 4.38788 5.90893 4.95321 3.61554 16500.00 1.72694 1.91927 2.19006 2.59824 3.14903 4.10699 5.07925 4.56090 3.78979 15000.00 1.77330 2.00255 2.29319 2.65191 3.12158 3.80953 4.30680 4.41224 4.82322 13500.00 1.83908 2.05466 2.31986 2.60449 3.02346 3.55032 4.23041 5.15838 4.77294 12000.00 1.88004 2.07889 2.27550 2.54431 2.90937 3.39582 4.02718 4.19786 3.89887 10500.00 1.85976 2.01640 2.23322 2.52109 2.84380 3.19113 3.53145 3.55035 3.41688 9000.00 1.84154 1.99316 2.21265 2.47291 2.73036 2.98165 3.20139 3.22819 3.18518 7500.00 1.81075 1.97946 2.17677 2.38435 2.57213 2.81369 300303 3.04083 3.08330 6000.00 1.77330 1.93424 2.11835 2.26635 2.46047 2.67700 2.83824 2.88956 3.00728 4500.00 1.72786 1.87269 2.01152 2.17661 2.36370 2.51917 2.64870 2.74803 2.88490 3000.00 1.69294 1.81536 1.95314 2.10136 2.25303 2.40195 2.53656 2.65672 2.80155 1500.00 1.64643 1.76152 1.89209 2.02629 2.16653 2.31846 2.44398 2.57234 2.75641 .00 I 1.60507 1.72527 1.83793 1.97225 2.09375 2.23559 2.37382 2.53059 2.71317 -1500.00 I 1.57442 1.68510 1.80630 1.92109 2.04859 2.17790 2.33097 2.47447 2.60217 -3000.00 I 1.54549 1.64945 1.75234 1.86129 1.97420 2.11360 2.23770 2.35336 2.46750 -4500.00 I 1.51622 1.60121 1.69771 1.79462 1.91246 2.03625 2.14463 2.25541 2.30755 -6000.00 I 1.47827 1.56050 1.65663 1.74772 1.85998 1.97712 2.07387 2.13418 2.18964 -7500.00 I 1.45118 1.53582 1.62380 1.71515 1.83180 1.92191 1.97794 2.03321 2.08768 -9000.00 I 1.42714 1.51075 1.58893 1.69120 1.76933 1.81481 1.87241 1.91517 1.98613 '" ISCST3 - VERSION 96113 ,', '" ANGLOGOLD - FREE STATE OPERATIONS 12/10/98 ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 30 "MODELOPTs: CONC RURAL FLAT FLGPOL '''THE ANNUAL ( 8736 HRS) AVERAGE CONCENTRATION VALUES FOR SOURCE GROUP: FREE INCLUDING SOURCE(S) FSOS2A, FSOS2B ,FSOS2C ,FSOS2D ,FSOS3 ,FSOS4 ,FSOS5A , FSOS5B ,FSOS6 ,FSOS8A ,FSOS8B ,FSOS8C ,FSOS9 ,FSOS10 ,FSOS11 ,FSOS12 ,FSOS13 ,FSOS17 ,FSOWC FSOWD ,FSOWE ,FSOWF ,FSOWG ,FSOWH ,FSOWI ,FSOWJ ,FSOWK ,FSOWL ,FSOWM ,FSOWN , . '" NETWORK ID: CART1 ; NETWORK TYPE: GRIDCART '" " CONC OF RADON IN BO/M3 Y-COORD I X-COORD (METERS) (METERS) I 8500.00 10000.00 11500.00 13000.00 14500.00 16000.00 17500.00 19000.00 20500.00 ------------------------------------------------------------------ 39000.00 .60880 .60934 .61286 .60674 .60694 .59009 .58092 .58600 .57692 37500.00 .65440 .64782 .64403 .63953 .63646 .62258 .61296 .61698 .60883 36000.00 .70343 .68449 .68963 .68084 .67649 .65785 .65157 .65491 .64067 34500.00 .75496 .73999 .73197 .72209 .71676 .70055 .69868 .69099 .67071 33000.00 .82321 .79064 .78193 .77226 .76382 .75192 .74326 .72545 .70933 31500.00 .88490 .85897 .83855 .82287 .81805 .79132 .78029 .76509 .74870 30000.00 .94815 .92103 .90890 .88290 .86015 .83813 .83232 .80671 .78828 28500.00 1.05304 1.02553 .99851 .94472 .92771 .89658 .88484 .86506 .83786 27000.00 1.15576 1.13937 1.07509 1.02065 .99214 .96376 .95321 .91898 .88903 25500.00 1.35062 1.28203 1.18089 1.10765 1.05913 1.02925 1.00080 .96752 .93861 24000.00 1.76326 1.45006 1.28810 1.21064 1.16323 1.11050 1.06971 1.02762 1.00828 22500.00 1.83889 1.58385 1.38820 1.29378 1.24755 1.18815 1.14653 1.11039 1.07962 21000.00 2.10328 1.72597 1.53652 1.41011 1.38447 1.31226 1.26887 1.20820 1.15219 19500.00 2.59275 1.98468 1.74507 1.60569 1.61119 1.54195 1.41392 1.30821 1.24369 18000.00 2.75686 2.32811 2.07195 1.99968 2.11320 1.85457 1.55662 1.41740 1.35008 16500.00 3.06927 2.49972 2.38584 3.20265 3.56315 2.23397 1.75315 1.58495 1.48685 15000.00 3.41353 2.63937 2.61561 3.16995 3.39433 2.23889 1.91533 1.76605 1.66129 13500.00 3.43999 2.85087 2.85459 3.18498 2.77383 2.30888 2.17673 2.00327 1.86526 12000.00 3.36194 2.99318 2.98196 3.09449 2.85958 2.69722 2.69946 2.40498 2.18412 10500.00 3.14275 2.97812 3.08429 3.28899 3.26947 3.75690 4.00865 3.10941 2.85163 A1-17 9000.00 I 3.06541 3.10019 3.43479 3.52767 3.70094 4.24862 4.88658 3.92519 4.35879 7500.00 I 3.09541 3.27465 3.64894 3.85452 4.47989 5.41774 5.46844 4.53943 4.95137 6000.00 I 3.16580 3.44975 3.92816 4.78254 5.43610 5.93134 5.90255 4.68986 4.58315 4500.00 I 3.11753 3.54214 4.45072 6.19091 5.96882 6.17561 5.14814 4.43493 4.54211 3000.00 I 3.06187 3.51504 4.35700 5.53579 5.32468 4.95485 4.56768 4.57290 5.73332 1500.00 I 3.03946 3.40385 3.99043 4.54296 4.43947 4.40704 4.23122 4.58294 5.87170 .00 I 2.92656 3.22125 3.64446 3.93664 3.85731 3.96772 3.98378 4.26317 4.84414 -1500.00 I 2.76811 3.01261 3.31436 3.52833 3.55141 3.67538 3.70928 3.95684 4.20795 -3000.00 I 2.58131 2.80248 3.02913 3.21359 3.27975 3.41804 3.50955 3.69951 4.02293 -4500.00 I 2.43132 2.59982 2.82259 2.99039 3.01272 3.15266 3.32231 3.68699 4.33161 -6000.00 I 2.30908 2.45871 2.62496 2.74189 2.75481 2.91654 3.09200 3.50528 4.69408 -7500.00 I 2.19101 2.31108 2.44400 2.53074 2.60389 2.76735 2.92817 3.28145 3.86910 -9000.00 I 207085 2.17225 2.29526 2.40548 2.47872 2.59673 2.71463 2.88754 3.11860 ••• ISCST3 - VERSION 96113 ••• ••• ANGLOGOLD - FREE STATE OPERATIONS 12110/98 ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 31 "MODELOPTs: CONC RURAL FLAT FLGPOL "'THE ANNUAL ( 8736 HRS) AVERAGE CONCENTRATION VALUES FOR SOURCE GROUP: FREE INCLUDING SOURCE(S): FSOS2A, FSOS2B ,FSOS2C ,FSOS2D, FSOS3 , FSOS4 ,FSOS5A , FSOS5B , FSOS6 , FSOS8A , FSOS8B ,FSOS8C ,FSOS9 , FSOS10 ,FSOS11 , FSOS12 ,FSOS13 ,FSOS17 , FSOWC FSOWD , FSOWE , FSOWF , FSOWG , FSOWH ,FSOWI , FSOWJ , FSOWK , FSOWL , FSOWM , FSOWN , . ••• NETWORK ID: CART1 ; NETWORK TYPE: GRIDCART ••• •• CONC OF RADON IN BQ/M3 Y-COORD I X-COORD (METERS) (METERS) I 22000.00 23500.00 25000.00 26500.00 28000.00 29500.00 31000.00 32500.00 ... _---- __ .... -----_._-_ ... _--------------------------._._ .... _--- 39000.00 .57932 .57348 .54746 .53325 .52056 .51095 .49900 .48611 37500.00 .60954 .59339 .57321 .55650 .54327 .53151 .51625 .50303 36000.00 .63395 .62049 .59746 .57903 .56830 .55183 .53557 .52449 34500.00 .66776 .65477 .62640 .60900 .59367 57624 .56033 .54813 33000.00 .70342 .69020 .65205 .63610 .62086 .60191 .58523 .56598 31500.00 .74292 .71807 .68068 .66665 .65232 .62875 .60366 .58388 30000.00 .78427 .75445 .71586 .70429 .68301 .65507 .63048 .60937 28500.00 .82823 .79002 .75507 .73960 .70930 .67300 .65275 .62515 27000.00 .87284 .82594 .79205 .76927 .73490 .70431 .67684 .64959 25500.00 .91983 .87073 .83342 .81025 .77444 .73915 .71262 .67891 24000.00 .97384 .91838 .88605 .86178 .81421 .77431 .74175 .70706 22500.00 1.03610 .97748 .94494 .90315 .85297 .81778 .78135 .73897 21000.00 1.09842 1.04288 1.00313 .95830 .90478 .86281 .81962 .77457 19500.00 1.17943 1.11285 1.07797 1.02664 .97170 .92652 .87281 .80556 18000.00 1.28075 1.22036 1.18023 1.11594 1.04350 .98682 .90814 .83715 16500.00 1.41734 1.35516 1.29019 1.21159 1.12611 1.03659 .95036 .87866 15000.00 1.57719 1.49739 1.41624 1.32097 1.19702 1.08518 1.00108 .92025 13500.00 1.80391 1.71839 1.63747 1.43292 1.27323 1.14342 1.03303 .93556 12000.00 2.12065 2.05055 1.82062 1.52748 1.33549 1.19489 1.07376 .97205 10500.00 2.90602 2.54405 1.95867 1.63951 1.42142 1.26038 1.12437 1.01720 9000.00 4.62795 2.90768 2.13985 1.78940 1.54326 1.34987 1.19603 1.07769 7500.00 4.09493 2.95667 2.32327 1.92268 1.64922 1.43004 1.26424 1.11390 6000.00 4.59074 3.56338 2.60383 2.07800 1.76193 1.52281 1.30884 1.16069 4500.00 4.88957 4.36744 2.86972 2.30778 1.93770 1.62774 1.37843 1.19465 3000.00 5.25617 3.87352 3.20046 2.84114 2.30297 1.71752 1.42909 1.22500 1500.00 5.01746 3.67108 3.70968 3.64411 2.46963 1.79661 1.46347 1.24081 .00 I 4.31471 3.83169 3.64333 3.15473 2.37661 1.77813 1.42731 1.19973 -1500.00 I 4.08045 3.97244 4.10078 3.63455 2.29273 1.74472 1.39106 1.17963 -3000.00 I 4.28094 5.10550 5.51177 4.00900 2.30936 1.72296 1.40341 1.19510 -4500.00 I 5.17282 5.27885 4.68553 3.05999 2.14438 1.65557 1.37147 1.16753 -6000.00 I 5.39542 4.28413 3.42333 2.50990 1.93828 1.55565 1.32679 1.14268 -7500.00 I 3.77284 3.34551 2.70103 2.13789 1.73903 1.45851 1.25458 1.10477 -9000.00 I 3.01953 2.75488 2.30077 1.86688 1.59599 1.37047 1.19253 106219 ••• ISCST3 - VERSION 96113 '" ••• ANGLOGOLD - FREE STATE OPERATIONS 12110/98 ... ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 32 "MODELOPTs: CONC RURAL FLAT FLGPOL '''THE ANNUAL ( 8736 HRS) AVERAGE CONCENTRATION VALUES FOR SOURCE GROUP: NL57 INCLUDING SOURCE(S): FSOS2A, FSOS2B ,FSOS2C ,FSOS2D ,FSOS3 ,FSOS4 ,FSOS5A , FSOS5B ,FSOS6 ,FSOS8A ,FSOS8B ,FSOS8C ,FSOS9 ,FSOS10 ,FSOS11 ,FSOS12 ,FSOS13 ,FSOS17 ,FSOWC FSOWD ,FSOWE ,FSOWF ,FSOWG ,FSOWH ,FSOWI ,FSOWJ ,FSOWK ,FSOWL ,FSOWM ,FSOWN , . ... NETWORK ID: CART1 , NETWORK TYPE: GRIDCART ••• .. CONC OF RADON IN BQ/M3 Y-COORD I X-COORD (METERS) (METERS) I -5000.00 -3500.00 -2000.00 -500.00 1000.00 2500.00 4000.00 5500.00 7000.00 ---. __ ._---------------------------------------------._._ ..... _--- 39000.00 I .23319 .23441 .24504 .25458 .26095 .26819 .27978 .29529 .30315 37500.00 I .25476 .25048 .25816 .27058 .28295 .28992 .29929 .31473 .32314 36000.00 I .28005 .26901 .27739 .28836 .30237 .31424 .32630 .33780 .34716 34500.00 I .30648 .29785 .29261 .31267 .32459 .34052 .35948 .36372 .37665 33000.00 I .33541 .33215 .32068 .33326 .35155 .37078 .39672 .40130 .41250 31500.00 I .36721 .37415 .36150 .35829 .38144 .41080 .43471 .45136 .45836 30000.00 I .39919 .41955 .41810 .40312 .42092 .44805 .48687 .51098 .52065 28500.00 I .42585 .45028 .47723 .47716 .47475 .50304 .54347 .58123 .59961 27000.00 I .47135 .49987 .52682 .54535 .54454 .59000 .63652 .67878 .69902 25500.00 I .55479 .56361 .59472 .62762 .64328 .67274 .75863 .82751 .85088 24000.00 I .67999 .69452 .71398 .75369 .78901 .82755 .92745 1.03769 1.13729 22500.00 I .81914 .87277 .92713 .97432 1.04625 1.12278 1.28674 1.48295 1.43903 21000.00 I .94701 1.04673 1.17817 1.32539 1.50178 1.73640 2.23183 2.34386 1.90789 19500.00 I 1.02136 1.15766 1.34095 1.61559 2.07073 2.94411 4.38878 3.78785 2.85302 18000.00 I 1.07712 1.22670 1.43187 1.75516 2.40808 3.74690 5.31322 4.40272 3.07552 16500.00 I 1.11295 1.27951 1.52672 1.91808 2.47402 3.45457 4.46345 3.97390 3.21417 15000.00 I 1.15085 1.34874 1.61362 1.95959 2.43215 3.13792 3.66773 3.78412 4.19590 13500.00 I 1.19680 1.38579 1.62231 1.89802 2.30970 2.84586 3.54089 4.47390 4.08571 12000.00 I 1.22897 1.40321 1.56972 1.82005 2.17330 2.66574 3.30509 3.45824 3.13676 A1-18 10500.00 I 1.20640 1.33485 1.52348 1.78678 2.09476 2.43655 2.77355 2.77003 2.59773 9000.00 I 1.18738 1.30816 1.49594 1.72477 1.95762 2.19484 2.40486 2.39822 2.30248 7500.00 I 1.15033 1.28751 1.45051 1.62481 1.78180 1.99923 2.16137 2.14579 2.11529 6000.00 I 1.10788 1.23134 1.37496 1.48462 1.63877 1.81913 1.94279 1.93155 1.96053 4500.00 I 1.07077 1.17642 1.26811 1.38918 1.53319 1.65341 1.73942 1.75313 1.80790 3000.00 I 1.03689 1.12045 1.21688 1.32633 1.43362 1.53701 1.60216 1.64893 1.70983 1500.00 I .99830 1.07729 1.16540 1.24997 1.33571 1.42660 1.49846 1.55321 1.63373 .00 I .95705 1.02905 1.09463 1.17653 1.24953 1.34301 1.43619 1.49833 1.57131 -1500.00 I .91673 .98399 1.05712 1.12831 1.20333 1.28944 1.36417 1.43047 1.46357 -3000.00 I .89892 .95897 1.02047 1.08169 1.14885 1.22735 1.30039 1.34231 1.33052 -4500.00 I .87743 .92323 .97771 1.02917 1.09635 1.18092 1.22253 1.24219 1.20038 -6000.00 I .84383 .88704 .93927 .98564 1.05882 1.10985 1.14510 1.12585 1.10796 -7500.00 I .81103 .85364 .90394 .95368 1.00747 1.04214 1.04854 1.04383 1.02943 -9000.00 I .78136 .83273 .86787 .91532 .94808 .96210 .97666 .97531 .97074 ••• ISCST3 - VERSION 96113 ••• ••• ANGLOGOLD - FREE STATE OPERATIONS 12/10/98 _. ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 33 "MODELOPTs: CONC RURAL FLAT FLGPOL "'THE ANNUAL ( 8736 HRS) AVERAGE CONCENTRATION VALUES FOR SOURCE GROUP: NL57 INCLUDING SOURCE(S): FSOS2A, FSOS2B ,FSOS2C ,FSOS2D ,FSOS3 ,FSOS4 ,FSOS5A , FSOS5B ,FSOS6 ,FSOS8A, FSOS8B ,FSOS8C ,FSOS9 ,FSOS10 ,FSOS11 ,FSOS12 ,FSOS13 ,FSOS17 ,FSOWC FSOWD ,FSOWE ,FSOWF ,FSOWG ,FSOWH ,FSOWI ,FSOWJ ,FSOWK ,FSOWL ,FSOWM ,FSOWN , . -- NETWORK ID: CART1 NETWORK TYPE: GRIDCART ••• •• CONC OF RADON IN BQ/M3 V-COORD I X-COORD (METERS) (METERS) I 8500.00 10000.00 11500.00 13000.00 14500.00 16000.00 17500.00 19000.00 20500.00 -------------------- __ ._-_._--------------.- .. _----_ ..... __ .... _-. 39000.00 .32220 .32737 .33581 .33726 .33892 .33015 .31984 .32440 .31313 37500.00 .34602 .35045 .36094 .36059 .36072 .35218 .34352 .34602 .33476 36000.00 .37230 .37711 .38741 .38809 .38590 .37582 .37054 .37228 .35451 34500.00 .40140 .40796 .41686 .41673 .41538 .40471 .40377 .39469 .36937 33000.00 .43457 .44547 .45612 .45378 .45099 .44210 .43102 .41390 .39243 31500.00 .47464 .49552 .50081 .49466 .49382 .47243 .45737 .44146 .41615 30000.00 .52436 .54824 .56311 .55137 .52834 .50802 .49536 .46740 .43952 28500.00 .59536 .61835 .62841 .59558 .57833 .54783 .52992 .50398 .46868 27000.00 .69938 .72791 .68744 .65487 .62892 .59892 .58145 .53808 .50050 25500.00 .88880 .86081 .78440 .73221 .68999 .65301 .61149 .56382 .52554 24000.00 1.28693 1.01649 .87502 .81445 .77157 .71761 .66581 .60444 .57159 22500.00 1.35614 1.13268 .95782 .87548 .83359 .77635 .71731 .65696 .61387 21000.00 1.61196 1.25416 1.08216 .96265 .94231 .87650 .81136 .72517 .64883 19500.00 2.09108 1.48925 1.26277 1.12726 1.12496 1.06183 .92210 .78849 .69464 18000.00 2.23480 1.81224 1.54999 1.48163 1.58064 1.31208 1.00964 .85292 .74711 16500.00 2.50374 1.94072 1.82757 2.62974 2.98385 1.61369 1.12584 .94717 .81751 15000.00 2.79152 2.01585 1.98487 2.51996 2.73483 1.54207 1.19674 1.02642 .89113 13500.00 2.75073 2.13923 2.12408 2.42026 1.98287 1.49234 1.31465 1.14543 .97434 12000.00 2.57216 2.18602 2.13551 2.14742 1.85793 1.61927 1.62569 1.33568 1.06502 10500.00 2.28801 2.06198 2.04849 2.02647 1.95820 2.07753 2.59111 1.61167 1.17242 9000.00 2.10854 2.04922 2.18131 2.19866 2.21312 2.53490 3.10464 1.88516 1.23773 7500.00 2.03730 2.08803 2.28650 2.45171 2.82850 3.52567 3.44849 2.00511 1.26945 6000.00 2.02389 2.18391 2.50270 3.21533 3.66349 3.98839 3.72529 2.07153 1.27736 4500.00 1.92467 2.20798 2.94565 4.50521 4.10186 4.07022 2.82865 1.74796 1.20793 3000.00 1.84600 2.14287 2.81929 3.81093 3.31122 2.80079 2.08593 1.44117 1.09911 1500.00 1.78631 2.01463 2.38792 2.68723 2.41938 2.12895 1.67097 1.21860 .99556 .00 I 1.65701 1.77028 2.00411 209479 1.90413 1.71434 1.40930 1.08301 .91176 -1500.00 I 1.48542 1.57606 1.69525 1.73909 1.58585 1.43136 1.22145 .97412 .83707 -3000.00 I 1.33748 1.40499 1.48789 1.48649 1.35225 1.23512 1.06988 .88207 .78047 -4500.00 I 1.21910 1.26339 1.32551 1.30436 1.18154 1.09143 .94577 .80485 .73161 -6000.00 I 1.12664 1.14975 1.18278 1.15865 1.05390 .97883 .84884 .73377 .68638 -7500.00 I 1.04140 1.05749 1.06821 1.03831 .95289 .88693 .77309 .67349 .63394 -9000.00 I .96538 .96885 .97429 .94180 .87113 .80996 .71142 .62144 .58586 ••• ISCST3 - VERSION 96113 ••• • •• ANGLOGOLD - FREE STATE OPERATIONS 12/10/98 ••• ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 34 "MODELOPTs: CONC RURAL FLAT FLGPOL ... THE ANNUAL ( 8736 HRS) AVERAGE CONCENTRATION VALUES FOR SOURCE GROUP: NL57 INCLUDING SOURCE(S): FSOS2A, FSOS2B , FSOS2C ,FSOS2D ,FSOS3 ,FSOS4 ,FSOS5A , FSOS5B ,FSOS6 ,FSOS8A , FSOS8B , FSOS8C ,FSOS9 ,FSOS1 0 ,FSOS11 ,FSOS12 , FSOS13 ,FSOS17 , FSOWC FSOWD ,FSOWE ,FSOWF ,FSOWG ,FSOWH ,FSOWI ,FSOWJ ,FSOWK ,FSOWL ,FSOWM ,FSOWN , .- NETWORK ID: CART1 ; NETWORK TYPE: GRIDCART'" - CONC OF RADON IN BQ/M3 •• V-COORD I X-COORD (METERS) (METERS) I 22000.00 23500.00 25000.00 26500.00 28000.00 29500.00 31000.00 32500.00 .... ----. __ ._-_._------------------- ....... _---_. __ ... --- ... - ... _- 39000.00 I .31004 .30771 .29406 .28113 .26673 .25561 .24546 .23522 37500.00 I .32896 .31664 .30714 .29142 .27661 .26518 .25244 .24236 36000.00 I .34056 .33299 .32103 .30172 .28835 .27227 .25958 .25058 34500.00 I .35949 .35163 .33440 .31374 .29535 .28010 .26978 .26041 33000.00 I .38080 .37091 .34406 .32340 .30497 .29257 .28205 .26636 31500.00 I .40398 .38318 .35757 .33631 .32039 .30439 .28544 .26852 30000.00 I .42713 .40204 .37256 .34971 .33030 .31176 .29200 .27597 28500.00 I .44917 .41972 .39028 .36485 .33893 .31422 .29675 .27963 27000.00 I .47127 .43265 .39968 .36836 .34164 .32212 .30263 .28621 25500.00 I .49615 .45298 .41442 .38181 .35832 .33699 .31678 .29927 24000.00 I .52291 .47102 .43221 .40312 .37529 .34682 .32488 .30784 22500.00 I .55380 .49729 .45332 .41696 .38525 .36143 .34142 .31864 21000.00 I .57683 .51794 .47287 .43608 .40262 .37750 .35227 .32897 19500.00 I .60779 .54420 .49708 .45918 .43163 .40204 .37294 .34576 18000.00 I .65470 .59256 .54377 .50050 .45858 .42098 .38610 .35684 165QO.00 I .72182 .64878 .58796 .53277 .48223 .43546 .39908 .37026 15000.00 I .77594 .69115 .61509 .54960 .49192 .44852 .41160 .37800 13500.00 I .84051 .72284 .63077 .55513 .49920 .45148 .40985 .37267 12000.00 I .88204 .75474 .64083 .55673 .49484 .44236 .39778 .36553 10500.00 I .92514 .75068 .64512 .55879 .48900 .43911 .40241 .37028 9000.00 I .93495 .75818 .63165 .55678 .49799 .44793 .41010 .37955 7500.00 I .92876 .75604 .64371 .56394 .50401 .45660 .41513 .38052 A1-19 6000.00 I .94769 .76766 .65194 .56999 .50595 .45734 .41868 .38580 4500.00 I .94147 .76754 .65438 .57387 .51463 .46468 .42439 .39199 3000.00 I .88906 .73899 .63409 .55524 .49507 .45231 .41696 .38612 1500.00 I .83238 .70587 .60605 .53427 .48107 .43514 .39905 .36950 .00 I .77699 .67995 .59189 .51759 .46548 .42304 .38861 .36040 -1500.00 I .72745 .64216 .57450 .51180 .45444 .41379 .38116 .35113 -3000.00 I .68461 .60991 .54903 .49716 .45012 .40510 .37185 .34652 -4500.00 I .64532 .58521 .52776 .48131 .43838 .40174 .36617 .33726 -6000.00 I .61514 .55651 .51096 .46476 .42872 .39242 .36262 .33494 -7500.00 I .58713 .52937 .49097 .45335 .41621 .38588 .35540 .33060 -9000.00 I .55699 .50906 .47221 .43923 .40607 .37763 .35043 .32483 ••• ISCST3 - VERSION 96113 ••• ••• ANGLOGOLD - FREE STATE OPERATIONS 12/10/98 _. ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 35 "MODELOPTs: CONC RURAL FLAT FLGPOL ••• THE SUMMARY OF MAXIMUM PERIOD ( 8736 HRS) RESULTS ••• - CONC OF RADON IN BO/M3 NETWORK GROUP ID AVERAGE CONC RECEPTOR (XR, YR, ZELEV, ZFLAG) OF TYPE GRID-ID ARM 1ST HIGHEST VALUE IS 2.03167 AT ( 14500.00, 16500.00, .00, 1.50) GC CA Rn 2ND HIGHEST VALUE IS 1.72411 AT ( 14500.00, 15000.00, .00, 1.50) GC CART1 FSO 1ST HIGHEST VALUE IS 5.12445AT( 4000.00, 18000.00, .00, 1.50) GC CARn 2ND HIGHEST VALUE IS 4.27780 AT ( 4000.00, 16500.00, .00, 1.50) GC CART1 HARMONY 1ST HIGHEST VALUE IS 4.88643 AT ( 25000.00, -3000.00, .00, 1.50) GC CART1 2ND HIGHEST VALUE IS 4.76314 AT (20500.00, 1500.00, .00, 1.50) GC CARn LOR 1ST HIGHEST VALUE IS 1.58115 AT ( -500.00, 33000.00, 00, 1.50) GC CARn 2ND HIGHEST VALUE IS 1.25937 AT ( -500.00, 31500.00, .00, 1.50) GC CART1 KAD 1ST HIGHEST VALUE IS 1.23522 AT ( 4000.00, 28500.00, .00, 1.50) GC CART1 2ND HIGHEST VALUE IS .91894 AT ( 4000.00, 27000.00, .00, 1.50) GC CART1 FREE 1ST HIGHEST VALUE IS 6.19091 AT ( 13000.00, 4500.00, .00, 1.50) GC CART1 2ND HIGHEST VALUE IS 6.17561 AT ( 16000.00, 4500.00, .00, 1.50) GC CART1 NL57 1ST HIGHEST VALUE IS 5.31322 AT ( 4000.00, 18000.00, 00, 1.50) GC CARn 2ND HIGHEST VALUE IS 4.50521 AT (13000.00, 4500.00, .00, 1.50) GC CART1 ••• RECEPTOR TYPES: GC = GRIDCART GP = GRIDPOLR DC = DISCCART OP = DISCPOLR BD = BOUNDARY "'ISCST3 - VERSION 96113 •••••• ANGLOGOLD - FREE STATE OPERATIONS 12/10/98 ENVIRONMENTAL RADON MODELLING 12:53:08 PAGE 36 "MODELOPTs: CONC RURAL FLAT FLGPOL ••• Message Summary: ISCST3 Model Execution ••• --------- Summary of Total Messages -------- A Total of 0 Fatal Error Message(s) A Total of 0 Warning Message(s) A Total of 0 Informational Message(s) ........ FATAL ERROR MESSAGES •••••••• •~ NONE ••• ... ~ ... WARNING MESSAGES ... NONE ••• ••• ISCST3 Finishes Successfully'" A1-20 APPENDIX 2 EXCEL WATER MODEL The following provides an example of the water model used to determine the exposures from ground and surface water sources: EXPOSURE DUE TO CONSUMPTION OF FOODSTUFFS AND LIQUIDS FOR ACTUAL AND HYPOTHETICAL CRITICAL GROUPS (USING MEASURED VALUES FROM AEC) Water Intake Annual Consumptions, kg/a Adults 15 year 10 year 5 year 1_year Water& 730 600 350 300 260 Beverages Milk Products 250 300 300 300 300 Meat Products 100 100 75 50 20 Poultr 75 75 eo 35 15 Y Eggs 30 30 25 15 6 Grain Products 150 128 90 75 eo Leafy 130 111 78 65 52 Vegatables Roots & Fruits 170 145 102 85 68 Fish Products 25 10 10 5 1 A2-1 MODEL OF ALL PATHWAYS TO HUMAN EXPOSURE FROM GROUNDWATER (Roots, Fruits and Leavy vegatables) This model contains all the possible pathways to humans from the use of groundwater. Consumption intake and concentration factors used in this model are all from LG 1032. All values in green are LG 1032 references All values in blue are assumptions. All values in red are ICRP72 references All values in greya(e expott concentrations tQModel Roots: i GROUNDWATER SOIL ROOT VEGETABLES FRUIT Fruits LEAFY GRAINS VEGETABLES (Measured) WET DRY WET DRY WET DRY Nuclide BqII Bq/g Fv2 Bq/g Bq/g Bqlg Fv2 Bq/g Bq/g Bqlg Bqlg Fv2 Bq/g Bqlg Bq/g Fv2 Bq/g 20% Bqlg 10% Bq/g 15% Bq/g U-238 3.0E+OO 3.00E-03 1.51 E-Q2 4.53E-CE 9.06E-06 5.44E-CE 4.00E-04 1.20E-06 1.20E-07 1.32E-06 3.84E-05 5.06E-03 1.52E-05 2.28E-06 1.75E-05 7.50E-04 2.25E-06 i U-234 3.0E+OO 3.00E-03 1.51 E-02 4.53E-05 9.06E-06 5.44E-CE 4.00E-04 1.20E-06 1.20E-07 1.32E-06 3.84E-05 5.06E-03 1.52E-05 2.28E-06 1.75E-05 7.50E-04 2.25E-06 Th-23Q 3.0E+OO 3.00E-03 4.01E-04 1.20E-06 2.40E-07 1.44E-06 4.00E-04 1.20E-06 1.20E-07 1.32E-06 1A1E-06 5.00E-03 1.50E-05 2.25E-06 1.73E-CE 7.50E-04 2.25E-06 Ra-226 1.5E-01 1.48E-04 2.00E-02 2.96E-06 5.93E-07 3.56E-06 2.02E-Q2 2.99E-06 2.99E-07 3.29E-06 3.48E-06 2.01E-Q2 2.97E-06 4.45E-07 3.41E-06 5.12E-03 7.58E-07 Pb-210 2.9E-02 2.90E-05 1.00E-Q2 2.90E-07 5.81E-OO 3.49E-07 1.00E-Q2 2.90E-07 2.90E-06 3.19E-07 3.4OE-07 1.50E-02 4.36E-07 6.54E-OO 5.02E-07 2.52E-02 7.32E-07 Po-210 2.9E-02 2.90E-CE 1.10E-03 3.19E-06 6.38E-OO 3.83E-06 1.00E-03 2.90E-06 2.90E-OO 3.19E-06 3.64E-06 1.15E-03 3.34E-06 5.00E-OO 3.84E-06 1.50E-03 4.35E-08 U-235 2.1 E-02 2.10E-05 3.00E-Q2 6.30E-07 1.26E-07 7.56E-07 4.00E-04 8.40E-OO 8.40E-10 9.24E-OO 5.32E-07 1.00E-02 2.10E-07 3.15E-06 2.42E-07 1.30E-03 2.73E-08 Pa-231 2.1 E-02 2.10E-05 1.00E-02 2.10E-07 4.20E-06 2.52E-07 5.00E-03 1.05E-07 1.05E-06 1.16E-07 2,11E-07 8.00E-03 1.68E-07 2.52E-06 1.93E-07 2.00E-Q2 4.2OE-07 Ac-227 2.1E-02 2.10E-CE 2.00E-03 4.20E-06 8.40E-OO 5.04E-06 1.00E-03 2.10E-06 2.10E-OO 2.31E-06 4.2ZE·06 1.50E-03 3.15E-06 4.73E-OO 3.62E-06 3.00E-04 6.30E-09 Th-227 2.1E-02 2.10E-CE 8.00E-04 1.68E-06 3.36E-OO 2.02E-06 4.00E-04 8.40E-OO 8.40E-10 9.24E-OO 1.69E-06 1.00E-02 2.10E-07 3.15E-06 2.42E-07 1.00E-03 2..10E-06 Ra-223 2.1 E-02 2.10E-CE 4.00E-Q2 8.40E-07 1.68E-07 1.01E-06 4.00E-02 8.40E-07 8.40E-06 9.24E-07 9.83E-07 4.00E-02 8.40E-07 1.26E-07 9.66E-01 1.00E-02 2,10E-07 Th-232 2.6E-03 2.60E-06 8.00E-04 2.08E-09 4.16E-10 2.50E-09 4.00E-04 1.04E-OO 1.04E-10 1.14E-OO 2.09E-09 1.00E-02 2.60E-06 3.90E-09 2.99E-06 1.00E-03 2.60E-09 Th-228 2.6E-03 2.60E-06 8.00E-04 2.08E-09 4.16E-10 2.50E-OO 4.00E-04 1.04E-OO 1.04E-10 1.14E-OO 2.09E-09 1.00E-Q2 2.60E-06 3.90E-OO 2.99E-06 1.00E-03 2.60E-09 Ra-228 2.6E-03 2.60E-06 4.00E-02 1.04E-07 2.08E-06 1.25E-07 4.00E-Q2 1.04E-07 1.04E-06 1.14E-07 1,22E-07 4.00E-02 1.04E-07 1.56E-06 1,20E-07 1.00E-Q2 2.60E-06 Ra-224 2.6E-03 2.60E-06 4.00E-Q2 1.04E-07 2.08E-06 1.25E-07 4.00E-02 1.04E-07 1.04E-06 1.14E-07 1,22E-07 4.00E-02 1.04E-07 1.56E-OO 1.2OE-07 1.00E-Q2 2.60E-06 A2-2 MODEL OF All PATHWAYS TO HUMAN EXPOSURE FROM GROUNDWATER (Milk Products) Sheep, goats, pigs GROUNDWATER SOil PLANTS Intake Intake Activity In Activity In Activity In Milk Milk Milk (Measured) Pasture, grass, browse Soil Dry Feed Water Dry solid food intake Water intake Total Cow Sheep (90%1 Nuclide Bqll Bq/g Fvl Bq/g 20% kg/d 4 lid 15 Units/dil BqII Fm Sheep (10%) Bq/g Bq/d Bq/d Fm Units/dil Bqll Bqll Comb Bq/I U-238 3.000 3.00E-03 1.00E-Ol 3.00E-04 3.60E-04 1.44E+OO 4.50E+Ol 3.42E-04 4.92E-04 3.42E-04 1.54E-02 1.59E-02 7.32E-02 U-234 3.000 3.00E-03 1.00E-Ol 3.00E-04 3.60E-04 1.44E+OO 4.50E+Ol 3.42E-04 4.92E-04 3.42E-04 1.54E-02 1.59E-02 7.3'2E-02 Th-23Q 3.000 3.00E-03 5.00E-02 1.50E-04 1.80E-04 7.20E-Ol 4.50E+Ol 3.75E-06 2.70E-06 3.75E-06 1.69E-04 1.71 E-04 7.908-04 Ra-226 0.148 1.48E-04 2.01 E-Ol 2.97E-a5 3.56E-Cl5 1.42E-Ol 2.22E+OO 6.54E-04 9.31E-a5 6.54E-04 1.45E-03 1.54E-03 7..14E-03 Pb-210 0.029 2.90E-Cl5 2.50E-Ol 7.25E-06 8.70E-06 3.48E-02 4.35E-Ol 1.65E-04 5.74E-06 1.65E-04 7.18E-Cl5 7.75E-Cl5 3.59£-04 Po-210 0.029 2.90E-Cl5 5.03E-02 1.46E-06 1.75E-06 6.99E-03 4.35E-Ol 1.55E-03 1.OSE-Cl5 1.55E-03 6.74E-04 6.85E-04 3.16E..CJ3 U-235 0.021 2.10E-a5 2.00E-Ol 4.20E-06 5.04E-06 2.02E-02 3.15E-Ol 6.00E-04 1.21 E-Cl5 6.00E-04 1.89E-04 2.01E-04 9.3OE-04 Pa-231 0.021 2.10E-a5 t.oos-ot 2.10E-06 2.52E-06 1.01 E-02 3.15E-Ol 5.00E-06 5.04E-06 5.00E-06 1.58E-06 1.63E-06 7.50E-06 Ac-227 0.021 2.10E-a5 1.00E-Ol 2.10E-06 2.52E-06 1.01 E-02 3.15E-Ol 2.00E-04 2.02E-06 2.00E-04 6.30E-a5 6.50E-Cl5 3.00E-04 Th-227 0.021 2.10E-a5 1.00E-Ol 2.10E-06 2.52E-06 1.01 E-02 3.15E-Ol 5.00E-06 5.04E-06 5.00E-06 1.58E-06 1.63E-06 7,50E-06 Ra-223 0.021 2.10E-Cl5 4.00E-Ol 8.40E-06 1.01 E-Cl5 4.03E-02 3.15E-Ol 1.30E-03 5.24E-Cl5 1.30E-03 4.10E-04 4.62E-04 '2.15E-m Th-232 0.003 2.60E-06 1.00E-Ol 2.60E-07 3.12E-07 1.25E-03 3.90E-02 5.00E-06 6.24E-OO 5.00E-06 1.95E-07 2.01E-07 9,28É-07 Th-228 0.003 2.60E-06 1.00E-Ol 2.60E-07 3.12E-07 1.25E-03 3.90E-02 5.00E-06 6.24E-OO 5.00E-06 1.95E-07 2.01E-07 9.281:-07 Ra-228 0.003 2.60E-06 4.00E-Ol 1.04E-06 1.25E-06 4.99E-03 3.90E-02 1.30E-03 6.49E-06 1.30E-03 5.07E-Cl5 5.72E-Cl5 2.66E-04 Ra-224 0.003 2.60E-06 4.00E-Ol 1.04E-06 1.25E-06 4.99E-03 3.90E-02 1.30E-03 6.49E-06 1.30E-03 5.07E-Cl5 5.72E-a5 2.66E-04 A2-3 Cattle GROUNDWATER SOil PLANTS Intake Intake Activity in Activity in Activity in Milk Milk Milk (Measured) Pasture, grass, browse Soii Dry Feed Water Dry solid food intake Water intake Total Cow I Cattle (90%) Nuclide BqII Bqlg Fv1 Bq/g 5% kg/d 25 lId 75 Units/dil Bqll Fm BqII Sheep (10%) Bqlg Bq/d Bq/d Fm Units/dil Bqll Comb BqII U-238 3.000 3.00ECOO 1.00E-01 3.00E-04 3.15E-04 7.88E+00 2.25E+02 3.42E-04 2.69E-03 3.42E-04 7.68E-02 7.95E-02 7.32E-02 U-234 3.000 3.00E-03 1.00E-01 3.00E-04 3.15E-04 7.88E+00 2.25E+02 3.42E-04 2.69E-03 3.42E-04 7.68E-02 7.95E-02 7.a2E-G2 Th-23Q 3.000 3.00E-03 5.00E-02 1.50E-04 1.58E-04 3.94E+00 2.25E+02 3.75E-06 1.48E-CS 3.75E-06 8.44E-04 8.59E-04 7"90£;-04 Ra-226 0.148 1.48E-04 2.01E-01 2.97E-05 3.12E-CS 7.79E-01 1.11E+01 6.54E-04 5.09E-04 6.54E-04 7.25E-03 7.76E-03 7.14l!-03 Pb-210 0.029 2.90E-05 2.50E-01 7.25E-06 7.62E-06 1.90E-01 2.18E+OO 1.65E-04 3.14E-05 1.65E-04 3.59E-04 3.90E-04 3~$96-04 Po-210 0.029 2.90E-CS 5.03E-02 1.46E-06 1.53E-06 3.83E-02 2.18E+OO 1.55E-03 5.93E-CS 1.55E-03 3.37E-03 3.43E-03 3.16E-03 U-235 0.021 2.10E-CS 2.00E-01 4.20E-06 4.41 E-06 1.10E-01 1.58E+OO 6.00E-04 6.62E-CS 6.00E-04 9.45E-04 1.01 E-03 9.$Oe-D4 Pa-231 0.021 2.10E-CS 1.00E-01 2.10E-06 2.21E-06 5.51E-02 1.58E+OO 5.00E-06 2.76E-07 5.00E-06 7.88E-06 8.15E-06 UhS-06 Ac-227 0.021 2.10E-05 1.00E-01 2.10E-06 2.21E-06 5.51E-02 1.58E+OO 2.00E-04 1.10E-CS 2.00E-04 3.15E-04 3.26E-04 3.00E..()4 Th-227 0.021 2.10E-05 1.00E-01 2.10E-06 2.21E-06 5.51 E-02 1.58E+OO 5.00E-06 2.76E-07 5.00E-06 7.88E-06 8.15E-06 7.50E-OO Ra-223 0.021 2.10E-CS 4.00E-01 8.40E-06 8.82E-06 2.21 E-01 1.58E+OO 1.30E-03 2.87E-04 1.30E-03 2.05E-03 2.33E-03 2.t5E~ Th-232 0.003 2.60E-06 1.00E-01 2.60E-07 2.73E-07 6.83E-03 1.95E-01 5.00E-06 3.41 E-08 5.00E-06 9.75E-07 1.01 E-06 '9.28E-07 Th-228 0.003 2.60E-06 1.00E-01 2.60E-07 2.73E-07 6.83E-03 1.95E-01 5.00E-06 3.41E-08 5.00E-06 9.75E-07 1.01E-06 9.28E-07 Ra-228 0.003 2.60E-06 4.00E-01 1.04E-06 1.09E-06 2.73E-02 1.95E-01 1.30E-03 3.55E-05 1.30E-03 2.54E-04 2.89E-04 2.666-04 Ra-224 0.003 2.60E-06 4.00E-01 1.04E-06 1.09E-06 2.73E-02 1.95E-01 1.30E-03 3.55E-05 1.30E-03 2.54E-04 2.89E-04 2.66E-04 A2-4 MODEL OF ALL PATHWAYS TO HUMAN EXPOSURE FROM GROUNDWATER (Meat Products) Sheep, goats, pigs GROUNDWATER SOIL PLANTS Intake Intake ACTIVITY IN SHEEP,GOAT,PIG FLESH (Measured) Pasture, grass, browse Soil Dry Feed Water Daily Int Ff Activity Cattle:Sheep Nuclide BqII Bq/g Fv1 Bq/g 20% kg/d 4 Vd 15 Bq/d d1kg Bq/kg 50:50 Bq/g Bq/d Bq/d Bq/kg total U-238 3.000 3.00E-03 1.00E-01 3.00E-04 3.60E-04 1.44E+OO 4.50E+01 4.64E+01 1.5OE-02 6.97E-01 2.09.E+OO U-234 3.000 3.00E-03 1.00E-01 3.00E-04 3.60E-04 1.44E+OO 4.50E+01 4.64E+01 1.5OE-02 6.97E-01 2,OOË~ Th-23Q 3.000 3.00E-03 5.00E-02 1.50E-04 1.80E-04 7.20E-01 4.50E+01 4.57E+01 2.50E-03 1.14E-01 3.43E..Q1 Ra-226 0.148 1.48E-04 2.01 E-01 2.97E-CS 3.56E-05 1.42E-01 2.22E+OO 2.36E+OO 2.55E-03 6.02E-03 . 1.621;:02 Pb-210 0.029 2.90E-05 2.50E-01 7.25E-06 8.70E-06 3.48E-02 4.35E-01 4.70E-01 5.CSE-04 2.37E-04 7.16E-04 Po-210 0.029 2.90E-05 5.03E-02 1.46E-06 1.75E-06 6.99E-03 4.35E-01 4.42E-01 2.80E-03 1.24E-03 " 3i2E;03 U-235 0.021 2.10E-05 2.00E-01 4.20E-06 5.04E-06 2.02E-02 3.15E-01 3.35E-01 3.00E-02 1.01 E-02 3:cl3E-02 Pa-231 0.021 2.10E-CS 1.00E-01 2.10E-06 2.52E-06 1.01 E-02 3.15E-01 3.25E-01 5.00E-03 1.63E-03 4.89E.-03 Ac-227 0.021 2.10E-CS 1.00E-01 2.10E-06 2.52E-06 1.01 E-02 3.15E-01 3.25E-01 4.00E-04 1.30E-04 3:91E~04 Th-227 0.021 2.10E-CS 1.00E-01 2.10E-06 2.52E-06 1.01 E-02 3.15E-01 3.25E-01 5.00E-03 1.63E-03 4,89E-03 Ra-223 0.021 2.10E-05 4.00E-01 8.40E-06 1.01 E-CS 4.03E-02 3.15E-01 3.55E-01 5.00E-03 1.78E-03 sees-ee Th-232 0.003 2.60E-06 1.00E-01 2.60E-07 3.12E-07 1.25E-03 3.90E-02 4.02E-02 5.00E-03 2.01E-04 6,05E~04 Th-228 0.003 2.60E-06 1.00E-01 2.60E-07 3.12E-07 1.25E-03 3.90E-02 4.02E-02 5.00E-03 2.01E-04 6.05E-04 Ra-228 0.003 2.60E-06 4.00E-01 1.04E-06 1.25E-06 4.99E-03 3.90E-02 4.40E-02 5.00E-03 2.20E-04 5.6.6~&04 Ra-224 0.003 2.60E-06 4.00E-01 1.04E-06 1.25E-06 4.99E-03 3.90E-02 4.40E-02 5.00E-03 2.20E-04 -S.56E-04 -- --- A2-5 Cattle GROUNDWATER SOIL PLANTS Intake Intake ACTIVITY IN CATTLE FLESH (Measured) Pasture, grass, browse Soil Dry Feed Water Daily Int Ff Activity Cattle:Sheep Nuclide 8ql1 8q1g Fv1 8q/g 20% kg/d 4 lid 15 8q/d dlkg 8q/kg 50:50 8q/g 8q/d 8q/d 8q/kg total U-238 3.000 3.00E-03 1.00E-Q1 3.00E-04 3.60E-04 1.44E+OO 4.50E+01 2.33E+02 1.50E-02 3.49E+OO 2.09&!OO U-234 3.000 3.00E-03 1.00E-Q1 3.00E-04 3.15E-04 7.88E+OO 2.25E+02 2.33E+02 1.50E-02 3.49E+OO 2.09Eo+()() Th-23Q 3.000 3.00E-03 5.00E-02 1.50E-04 1.58E-04 3.94E+OO 2.25E+02 2.29E+02 2.50E-03 5.73E-01 3.43E,01· Ra-226 0.148 1.48E-04 2.01 E-01 2.97E-05 3.12E-05 7.79E-01 1.11 E+01 1.19E+01 2.55E-03 3.03E-02 1.82E.Q2 Pb-210 0.029 2.90E-05 2.50E-01 7.25E-06 7.62E-06 1.90E-01 2.18E+OO 2.37E+OO 5.05E-04 1.19E-03 7.16E-04 Po-210 0.029 2.90E-05 5.03E-02 1.46E-06 1.53E-06 3.83E-02 2.18E+OO 2.21 E+OO 2.80E-03 6.20E-03 3.72E-<03 U-235 0.021 2.10E-05 2.00E-01 4.20E-06 4.41 E-06 1.10E-01 1.58E+OO 1.69E+OO 3.00E-02 5.06E-02 3.03E..Q2 Pa-231 0.021 2.10E-05 1.00E-01 2.10E-06 2.21E-06 5.51E-02 1.58E+OO 1.63E+OO 5.00E-03 8.15E-03 4.896-03 Ac-227 0.021 2.10E-05 1.00E-01 2.10E-06 2.21E-06 5.51E-02 1.58E+OO 1.63E+OO 4.OOE-04 6.52E-04 3.91E-04 Th-227 0.021 2.10E-05 1.00E-01 2.10E-06 2.21E-06 5.51E-02 1.58E+OO 1.63E+OO 5.00E-03 8.15E-03 4.89E-03 Ra-223 0.021 2.10E-05 4.OOE-01 8.40E-06 8.82E-06 2.21 E-01 1.58E+OO 1.80E+OO 5.00E-03 8.98E-03 5".38E-03 Th-232 0.003 2.60E-06 1.00E-01 2.60E-07 2.73E-07 6.83E-03 1.95E-01 2.02E-01 5.00E-03 1.01E-03 6.05E-04 Th-228 0.003 2.60E-06 1.00E-01 2.60E-07 2.73E-07 6.83E-03 1.95E-01 2.02E-01 5.00E-03 1.01 E-03 6.056-04 Ra-228 0.003 2.60E-06 4.OOE-01 1.04E-06 1.09E-06 2.73E-02 1.95E-01 2.22E-01 5.00E-03 1.11 E-03 6.66e.:04 Ra-224 0.003 2.60E-06 4.OOE-01 1.04E-06 1.09E-06 2.73E-02 1.95E-01 2.22E-01 5.00E-03 1.11 E-03 5.56.E.:Q4 A2-6 MODEL OF All PATHWAYS TO HUMAN EXPOSURE FROM GROUNDWATER (Poulrty and eggs) GROUNDWATER SOil Plants DAilY Ratio Activity in Activity In INTAKE Meat Eggs (Measured) Pasture, grass, browse Plants Water Liquid:feed Ff - Poultry Ff - eggs Nuclide Bqll Bqlg Fv1 Bqlg kg/d 0.15 I/dO.3 2:1 UniUdlkg Bqlkg Unitld/kg Bqlkg Bq/d Bqld Bqld U-238 3.000 3.ooE-03 1.ooE-01 3.ooE-04 4.5OE-02 0.9 0.61500075 1.20E+00 7.3861,)1 1.ooE+OO ~,15E-01 U-234 3.000 3.ooE-03 1.ooE-01 3.ooE-04 4.5OE-02 0.9 0.61500075 1.20E+OO . « 7;:3sE~ 1.00E+OO $.15E-61 Th-23Q 3.000 3.ooE-03 5.ooE-02 1.5OE-04 2.25E-02 0.9 0.60750375 4.ooE-03 t.43E.:03 2.01E-03 1.22e-03 Ra-226 0.148 1.48E-04 2.01 E-01 2.97E-CS 4.45E-03 0.0444 0.0310837 9.90£-04 3 .0. 8e-oo 2.ooE-CS 6.22E-07 Pb-210 0.029 2.9O£-CS 2.5OE-01 7.25E-06 1.09E-03 0.0007 0.00616265 2.ooE-03 1~3E-óS 2.ooE-03 1.~E"(s Po-210 0.029 2.90E-CS 5.03E-02 1.46E-06 2.19E-04 0.0007 0.00587286 4.00E-03 " 2.3j5E~ 1.80E-02 1.06E-04 U-235 0.021 2.10E-CS 2.ooE-01 4.20E-06 6.3OE-04 0.0063 0.00441 1.ooE+OO ~4,MË-$ 1.ooE+00 4.4fE-OO Pa-231 0.021 2.10E-CS 1.ooE-01 2.10E-06 3.15E-04 0.0063 0.004305 1.ooE+00 4.3.1~ 1.00E+00 4.31E..q3 Ac-227 0.021 2.10E-CS 1.ooE-01 2.10E-06 3.15E-04 0.0063 0.004305 1.ooE+00 ·4.átË.03 1.ooE+00 4.3tE-~ Th-227 0.021 2.10E-CS 1.ooE-01 2.10E-06 3.15E-04 0.0063 0.004305 1.ooE+00 431E..Q3 1.ooE+00 4.31E-03 Ra-223 0.021 2.10E-CS 4.ooE-01 8.4OE-06 1.26E-03 0.0063 0.00462 1.ooE+00 1'l'4.~E:ro 100E+OO 4.62E-93 Th-232 0.003 2.60E-06 1.ooE-01 2.60E-07 3.90E-CS 0.0008 0.000533 1.ooE+00 5.33E.Q4 1.ooE+OO 15.;33E...Q4 Th-228 0.003 2.60E-06 1.ooE-01 2.60E-07 3.90E-CS 0.0008 0.000533 1.ooE+OO' .$.33I:.-D4 1.ooE+00 5.33£-04 Ra-228 0.003 2.60E-06 4.ooE-01 1.04E-06 1.56E-04 0.0008 0.OOCS72 1.ooE+00 5.72E-04 1.ooE+00 5,72E-04 Ra-224 0.003 2.60E-06 4.ooE-01 1.04E-06 1.56E-04 0.0008 O.OOCS72 1.ooE+00 . ~5'.12E-t{4 1.ooE+OO 5.72E.,Q4 A2-7 BIBLIOGRAPHY: Aldenkamp RJ et al (1990), An assessment of a method for in situ radon exhalation measurements, Kernfysich Versneller Instituut, Croningen. 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However, the potential impact on the water sources should be assessed as part of the overall water management programmes on the mines, with radioactivity as one of the potential pollutants. Institutional controls will probably have to be established to prevent inadvertent public access to and settlement on tailings dams and surface process water dams. In conclusion, it seems that the potential exposures to the public from the mines in the Free State Goldfields are well within the principles of ALARA, i.e. doses are As Low as Reasonably Achievable, considering social and economic factors. SUMMARY: The gold mines In the Free State Goldfields extract and process ore from underground, which contains naturally radioactive uranium and its associated decay products. This assessment aimed to cost effectively determine the major potential radiation hazards to the public from the gold mines in the area. The potential exposure sources from the mines are radon gas, radioactive dust, contaminated water and external gamma radiation. The assessment focussed mainly on the public's potential exposure to radon gas emanating from tailings dams, waste rock dumps and upeast shafts from underground workings. The rate of radon emanation from the dams was measured using several different techniques, and the potential dispersion of the radon was modelled using internationally accepted modelling codes and local weather data for the Free State Goldfields. A maximum potential contribution to the natural background radon levels of 6 Bq m-3 was calculated. This is a small increment to the background levels in the order of 25 to 35 Bq rn". Environmental measurements of outdoor radon concentrations confirmed the modelling results to the extent that no significantly high radon concentration could be detected in the environment. Background radon levels in towns outside the Free State Goldfields are in the same order as those measured around the mines. Similar environmental measurements of airborne dust and water sources around the mines indicated relatively low levels of radiation. A conservative estimate of the total potential exposure of the public in the Free State Goldfields is in the order of 130 to 250 I-lSv/a. This can be interpreted as well within the internationally accepted public dose limit of 1000 I-lSv/a. , '3 I 5~ I 811