04 tm origin of sandstone tanzania session-8

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04 tm origin of sandstone tanzania session-8

  1. 1. SANDSTONE-HOSTED URANIUM MINERALIZATION INSELOUS GAME RESERVE AND ENVIRONMENTALISSUES : A CASE OF MKUJU RIVER PROJECT-TANZANIAD.A. MWALONGO, S.L.C MDOE AND I.S.N. MKILAHA
  2. 2. CONTENTS1. INTRODUCTION2. OBJECTIVES3. U MINERALIZATION4. ENVIRONMENTAL ISSUES5. METHODOLOGY6. RESULTS7. CONCLUSION
  3. 3. INTRODUCTION• Uranium mining is treated differently than other mines!• The environmental Impact Statement (EIS) during approval process• Higher level of community concern in relation to uranium mining than with other mining activities• Lack of trust consultants/contractors EIA reports• Increase cost and Delays – The Community perceptions; – The actual and perceived risks
  4. 4. OBJECTIVES OF THIS PRESENTATION(I)BRIEF OVERVIEW OF URANIUM MINERALIZATION IN TANZANIA(I)TO ESTABLISH A PRELIMINARY BASELINE RADIOACTIVITY LEVELS
  5. 5. U MINERALIZATION IN TANZANIAGeosurvey International in 1976-1980 carried out uraniumexploration on country wideFurther ground follow-up was undertaken by Uranerzbergbau ofGermany in 1978-82 Airborne geophysical survey comprising magnetics, radiometricand electromagnetic methods was carried out all over the countrySpacing of the flight lines was 1 km and tie lines 10 kmPotential for follow up work suggested:Sandstone and siltstone of Karroo System;Igneous/intrusive type; -Carbonatite; and -Intra-intrusive rocks.Hydrothermal type; - Unconformity vein type in Ubendian and Karagwe-Ankolean SystemPhosphate rocks; Superficial calcrete and mbuga deposits; andRadioactive beach sand.
  6. 6. THE DISTRIBUTION OF THE RADIOMETRIC ANOMALIES
  7. 7. Selous Game Reserve (SGR)U Anomalies• Tabular Sandstone-hosted uranium deposit• The SGR is the largest game reserve in Africa and includes two national parks• It was declared a natural world heritage site in 1982 by UNESCO• The discovery alarmed the public and encounters oppositions from public and civil societie• The baseline radiological studies were conducted by non partial audience to characterize the initial conditions
  8. 8. SGR RADIOMETRIC MAP
  9. 9. LOCAL GEOLOGYThe local geology of the project is located in large intracratonic basin filled with clastic sedimentsThe uranium mineralization is a tabular occurs intestinally in the course sandstones and conglomerate channelThree trap lithologies namely: (i) Arkose unit containing carbonaceous debris, carbonaceous siltstone rip-up and mercasite/pyrite concretions (ii) Permeable coarser sandstones with marcasite concretions and fine joints and clay development in the matrix of permeable stratigraphy (iii) The oxidized organic rich outer zones where mineralized layers exposed on the sides of the steep hillsThe rich outer zones are caused by uranium concentration andupgrading as a direct result of reducing environment caused byincrease in organic materials
  10. 10. ENVIRONMENTAL ISSUES!!
  11. 11. WILD HABITAT!
  12. 12. Why?Independent information for:Regulatory authorities government AuthoritiesEnvironmentalistThe public,Politicians; andGovernment officials
  13. 13. High Purity Germanium (HPGe) detector was usedRelative efficiency of 55% and resolution of 1.70 keV at 1332 keV energy of 60CoThe detector chamber was shielded with three layers of copper, cadmium and Lead of 30 mm, 3 mm and 100 mm thick, respectively Soil, sediment and surface water, food crops and Vegetations commonly feed by wild animals samples were measured The performance of the system was validated using IAEA reference materials like soil 375, the experimental values were within ± 5 %
  14. 14. RESULTS
  15. 15. ACTIVITY CONCENTRATION IN SOILMaximum activity concentration of 238U and 232Th and 40K in soil samples compared to the control (7*)Any significant deviation from these values in future may be attributed to the uranium mining processes
  16. 16. Activity Concentration in sedimentsThe activity concentrations of 238U and 232Th and 40K radionuclide were higher than the control samples As expected, the activity concentration of the 238U, 232Th and 40K in the sediment samples were much higher than those found in control samples
  17. 17. Activity Concentration in waterThe activity concentrations 238U in the samples from Mkuju were slightly higher than the mean value in control sampleThe activities of radionuclides in the analyzed water samples were comparableThe activities were also in the same range as the activity in the control sample The samples from wet Mkuju River had slightly higher activity concentration than other three samples
  18. 18. Activity Concentration in food cropsThe results show highest average activity concentration of238U, 232Th and 40K in from maize samples while cassava tuberand millet grains have lowest activity concentration.
  19. 19. Activity Concentration in wild vegetation feed by wild animals The results showed elevated activity concentration of radionuclides 238U and 232Th in weeds sampled from riverbank than in grass Wild fruits showed lowest activity concentrations for all radionuclides The activity concentration is typical grass shows lowest activity concentrations which are commonly fed by animals d animals
  20. 20. 6. CONCLUSIONThe baseline information presented compared withenvironmental data collected once the mine isoperational, will be used as a basis to evaluate potentialenvironmental impacts of the mine operationsThe radiological baseline studies are important to build public trust about the industryThe Wildlife Act of 2009 has weakened the legal basis for World heritageHowever, the status of to whether mining and milling activities will take place or not awaits UNESCO discretion
  21. 21. THANK YOU!

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