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Jan Slezak, Uranium Resource Specialist Nuclear Fuel Cycle & Materials Section

Uranium Geology and Deposits, Exploration, Mining and Milling and Environmental Issues Seminar on Nuclear Science and Technology for Diplomats Vienna, 6 – 8 February 2007. Jan Slezak, Uranium Resource Specialist Nuclear Fuel Cycle & Materials Section

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Jan Slezak, Uranium Resource Specialist Nuclear Fuel Cycle & Materials Section

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  1. Uranium Geology and Deposits, Exploration, Mining and Milling and Environmental IssuesSeminar on Nuclear Science and Technology for DiplomatsVienna, 6 – 8 February 2007 Jan Slezak, Uranium Resource Specialist Nuclear Fuel Cycle & Materials Section Division of Nuclear Fuel Cycle and Waste Technology

  2. Introduction • Uranium Geology & Deposits • Uranium Resources, Supply & Demand • Uranium Exploration • Uranium Mining • Uranium Milling • Associated Environmental Issues

  3. Uranium • Uranium as an element • The heaviest naturally occurring element(three main isotopes U-234, 235-0.71%, 238-99.28%) • U+4 (reduced-insoluble) & U+6 (oxidized-soluble) • Uranium minerals • Oxides: uraninite (crystalline UO2-2.6), pitchblende (amorphous UO2-2.6) • Silicates: coffinite (U(SiO4)1-x(OH)4x) • Phosphates • Organic complexes & other forms • Uranium occurrence • Uranium present almost everywhere, but in low concentrations • Natural concentrations in rocks: 0.0X (alkalic) – X (acidic) ppm • Concentration of uranium in the environment > URANIUM DEPOSIT

  4. Uranium minerals: Autunite & Torbernite

  5. Uranium Geology & Deposits • Uranium Geology • Source rock of uranium (X ppm) > process of removal > concentration in favorable conditions (X000 ppm) > ?URANIUM DEPOSIT • Uranium occurrence: A naturally occurring, anomalous concentration of uranium • Uranium deposit: A mass of naturally occurring mineral from which uranium could be exploited at present or in the future (under given economic conditions) • 13 Geologic Types of Uranium Deposits • Unconformity-related deposits (Canada, Australia) • Sandstone deposits (all over the word) • Hematite breccia complex deposits (only Australia – Olympic Dam) • Vein deposits (all over the word) • Intrusive deposits (Namibia)

  6. Unconformity-Type Deposit 10 20 meters 0 -500 m level -450 Outwash sand and gravel Shear zone Biotite gneiss Till Athabasca formation sandstone Block movement Pegmatoid Ore-bearing till (cobble ore horizon) Graphitic gneiss Ore body

  7. Sandstone Deposit

  8. Vein-Type Deposit

  9. Uranium ResourcesIdentified (Reasonably Assured + Inferred) Resources (in 1000 tonnes)

  10. Uranium Exploration • A complex process to find a uranium deposit – a defined model needed • Three main methods used: • Geological methods (remote sensing, geologic mapping, drilling, trenching etc.) • Geochemical methods (sampling, analyses, advanced methods-dating, isotope studies) • Geophysical methods (radiometric, geomagnetic, geoelectric, gravimetric, seicmic etc. methods and borehole logging)

  11. Field Uranium Exploration

  12. Definitions Mining The activity that removes from the earth’s crust the abnormal concentration of metal found in the deposit Mine An opening or excavation of the earth from which minerals are extracted

  13. Type of Mining • Open pit • Underground • In-situ Leach (ISL)

  14. Open Pit Mining • Mine working open to the surface • Operation designed to extract minerals that lie close to the surface • Waste is first removed, then the ore is broken and loaded

  15. Open Pit Mine

  16. Underground Mining • Access • Ramp or shaft or both • Method • Cut and fill • Stope and Pillar • Jet boring • Raise Boring

  17. Head Frame of Shaft

  18. Underground mine

  19. Underground Stope

  20. In Situ Leaching Elution/ Precipitation Circuit Evaporation Ponds IX Columns O2 CO2 Injection Pump Electrical Power lines Production Monitor Wells Monitor Wells Injection Wells Production Wells Shallow Monitor Deep Monitor Upper Aquifer Impermeable Zone Mineralized Aquifer Impermeable Zone Lower Aquifer Submersible Pump

  21. In-Situ Leaching Wellfield

  22. Milling Process • Size Reduction • Leaching • Solid - Liquid Separation • Purification and Concentration • Precipitation and Solid–Liquid Separation • Drying

  23. Milling Process Scheme

  24. The Mill

  25. Yellow Cake

  26. Uranium Production • 2004 40 263 tonnes U • 2003 35 492 tonnes U

  27. Mine Site at the End of Mining Operations

  28. Rehabilitation of Mining Site

  29. IAEA Thank you for your attention …atoms for peace.

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