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Mining Practices & Impacts

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A look at surface and subsurface mining methods as well as their environmental impacts.

Publicado en: Educación

Mining Practices & Impacts

  1. 1. Mining Practices and Impacts Derrick Willard
  2. 2. Why do we mine minerals?
  3. 3. Coal Types & Uses
  4. 4. Coal Found in 32 States Valued for energy and steel production
  5. 5. Identifying Mineral Deposits (costs $$$$$ to find them…) <ul><li>Aerial photos </li></ul><ul><li>Radiation detectors </li></ul><ul><li>Magnetometer </li></ul><ul><li>Gravimeter </li></ul><ul><li>Deep well drilling </li></ul><ul><li>Seismic survey </li></ul><ul><li>Chemical analysis </li></ul>
  6. 6. Acquiring Land for Mining <ul><li>The General Mining Law of 1872 has served to reduce “start up” costs and maximize profits for “hardrock” mineral companies in the U.S.A on public lands </li></ul><ul><ul><li>$2.50/acre fro an open-pit mine </li></ul></ul><ul><ul><li>$5/acre for a “vein” </li></ul></ul><ul><ul><li>No claim limit/claims don’t expire </li></ul></ul><ul><ul><li>No royalties have to be paid out </li></ul></ul>
  7. 7. Q. Just how much land are we talking about? A. About 270 million acres (or 1/4 of USA)
  8. 8. Mining Techniques <ul><li>Surface Mining </li></ul><ul><ul><li>Extracts 90% of nonfuel mineral and rock </li></ul></ul><ul><ul><li>Extracts 70% of coal </li></ul></ul><ul><li>Subsurface Mining </li></ul><ul><ul><li>Extracts coal and metal ores too deep to reach by surface mining </li></ul></ul>
  9. 9. Methods of Coal Mining
  10. 10. US Mining Trends
  11. 11. Pros and Cons Surface Subsurface -disturbs large area -produces large amounts of spoil -relatively safe -cheaper -more efficient -disturbs much smaller surface area -spoil often left in mine -dangerous -expensive -less efficient
  12. 12. Surface Mining <ul><li>Strip out overburden (becomes spoils) </li></ul><ul><li>Four land methods possible </li></ul><ul><ul><li>Open-pit (quarry) </li></ul></ul><ul><ul><li>Area strip mining (flat terrain) </li></ul></ul><ul><ul><li>Contour strip mining (hilly terrain) </li></ul></ul><ul><ul><li>Mountaintop removal </li></ul></ul><ul><li>Clean up (reclamation) </li></ul>
  13. 13. Overburden Removal
  14. 14. A Dragline Shovel
  15. 15. Mining Trucks <ul><li>*To the left is a photograph of a Liebherr 360 ton (327 metric ton) haul truck. This unit is powered by a 2750 horse power engine and weighs 443,000 pounds (177 tons) empty ... </li></ul>
  16. 16. Open Pit Copper Mine near Silver City, NM
  17. 17. Area Strip Mining
  18. 18. Area Strip Mine (Coal)
  19. 19. Contour (Bench) Strip Mining
  20. 20. Contour Mining in KY “ Highwalls”
  21. 21. The “New” Technique
  22. 22. Mountaintop Removal Mining
  23. 23. Mountaintop Removal and Valley Fill (WV) The top of a mountain has been pushed into a valley
  24. 24. Mountaintop Removal Coal Mine in Southern WV
  25. 25. Mountaintop(s) Removal near Kayford Mountain, WV
  26. 26. Mountaintop Removal-Up Close (spoil pile)
  27. 27. Subsurface Mining <ul><li>Deep vertical shafts used to reach coal and ores too deep for surface mines </li></ul><ul><ul><li>Blasting </li></ul></ul><ul><ul><li>Drilling and excavating machinery </li></ul></ul><ul><li>Once underground… </li></ul><ul><ul><li>Room-and-Pillar method (coal pillars) </li></ul></ul><ul><ul><li>Longwall method (metal supports) </li></ul></ul>
  28. 28. Subsurface Mine Types
  29. 29. Longwall Mining
  30. 30. Longwall Mining Machine
  31. 31. Room and Pillar Mining
  32. 32. Room and Pillar Mining
  33. 33. Room and Pillar Mining Machine
  34. 34. Load Out <ul><li>Regardless of how it is mined, coal is crushed into a standard size. Then the coal loaded onto trains for shipment across the U.S.A. to use for making steel and generating electricity. </li></ul>
  35. 35. Impacts of Mining Coal <ul><li>Scarring and disruption of area (ugly) </li></ul><ul><li>Erosion increases if reclamation not done properly </li></ul><ul><li>Subsidence (sinkholes) </li></ul><ul><li>Toxins released (dust, gas,drainage)--possible soil, air, water pollution </li></ul><ul><li>Acid mine drainage (esp. sulfur…) </li></ul><ul><li>Slurry (coal waste) pond overflow </li></ul>
  36. 36. Scarring in Tennessee
  37. 37. Subsidence over a Coal Shaft in Colorado
  38. 38. Coal Mine Subsidence in Colorado
  39. 39. Centralia, Pennsylvania (where a coal vein fire started in 1961)
  40. 40. Centralia, Pennsylvania (Helltown, USA)
  41. 41. Centralia, Pennsylvania (almost abandoned)
  42. 42. Centralia, Pennsylvania (Highway 61)
  43. 43. Acid Mine Drainage *results when the mineral pyrite (FeS 2 ) is exposed to air and water, resulting in the formation of sulfuric acid and iron hydroxide
  44. 44. Slurry Pond Spill in Kentucky October 2000
  45. 45. Surface Mining Control & Reclamation Act of 1977 <ul><li>Came about due to concerns about damage from strip mining </li></ul><ul><li>Regulates active mines and drives reclamation </li></ul><ul><li>Requires permits for mining </li></ul><ul><li>Allows for inspection and punishment </li></ul><ul><li>Requires companies post a bond before mining to ensure cleanup is done </li></ul><ul><li>Prohibits strip mines in National Parks </li></ul>
  46. 46. Reclamation Restoration of abandoned surface coal mine in Pennsylvania- now wild game lands
  47. 47. Sources for You to Explore <ul><li> </li></ul><ul><li> </li></ul><ul><li> </li></ul><ul><li> </li></ul><ul><li> </li></ul>