Mining Practices and Impacts

        Derrick Willard
Why do we mine things?
What is in the crust?



Bauxite Ore
(aluminum)




 *Very little in a pure state-most metallic minerals exist
             concentrated in rocks called ores
We also mine nonrenewable
        fossil fuels…
• Coal (focus of this presentation)
• Oil
• Natural Gas
Coal Types & Uses
Coal Found in 32 States




 Valued for energy and steel production
Identifying Mineral Deposits
    (costs $$$$$ to find them…)
•   Aerial photos
•   Radiation detectors
•   Magnetometer
•   Gravimeter
•   Deep well drilling
•   Seismic survey
•   Chemical analysis
Acquiring Land for Mining
• 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
  – $2.50/acre fro an open-pit mine
  – $5/acre for a “vein”
  – No claim limit/claims don’t expire
  – No royalties have to be paid out
Q. Just how much land are we talking about?




A. About 270 million acres (or 1/4 of USA)
Mining Techniques
• Surface Mining
  – Extracts 90% of nonfuel mineral and rock
  – Extracts 70% of coal
• Subsurface Mining
  – Extracts coal and metal ores too deep to
    reach by surface mining
Methods of Coal Mining
US Mining Trends
Pros and Cons
      Surface              Subsurface
-disturbs large area   -disturbs much
                       smaller surface area
-produces large        -spoil often left in
amounts of spoil       mine
-relatively safe       -dangerous
-cheaper               -expensive
-more efficient        -less efficient
Surface Mining
• Strip out overburden (becomes spoils or
  tailings)
• Five land methods possible
  –   Open-pit (quarry)
  –   Area strip mining (flat terrain)
  –   Contour strip mining (hilly terrain)
  –   Mountaintop removal*
  –   Placer mining (in riverbeds-usually gold or silver)
• Clean up (reclamation)
“Overburden” Removal
A Dragline Shovel
Mining Trucks
         *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...
Open Pit Copper Mine near
     Silver City, NM
Area Strip Mining
Area Strip Mine (Coal)
Contour (Bench) Strip Mining
Contour Mining in KY
                  “Highwalls”
The “New” Technique
Mountaintop Removal Mining
Mountaintop Removal and
    Valley Fill (WV)




The top of a mountain has been pushed into a valley
Mountaintop Removal Coal
  Mine in Southern WV
Mountaintop(s) Removal near
  Kayford Mountain, WV
Mountaintop Removal-Up
   Close (spoil pile)
Subsurface Mining
• Deep vertical shafts used to reach coal
  and ores too deep for surface mines
  – Blasting
  – Drilling and excavating machinery
• Once underground…
  – Room-and-Pillar method (coal pillars)
  – Longwall method (metal supports)
Subsurface Mine Types
Longwall Mining
Longwall Mining Machine
Room and Pillar Mining
Room and Pillar Mining
Room and Pillar Mining
      Machine
Load Out

      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.
Impacts of Mining Coal
• Scarring and disruption of area (ugly)
• Erosion increases if reclamation not
  done properly
• Subsidence (sinkholes)
• Toxins released (dust, gas,drainage)--
  possible soil, air, water pollution
• Acid mine drainage (esp. sulfur…)
• Slurry (coal waste) pond overflow
Scarring in Tennessee
Subsidence over a Coal Shaft
        in Colorado
Coal Mine Subsidence in
       Colorado
Centralia, Pennsylvania
(where a coal vein fire started in 1961)
Centralia, Pennsylvania
   (Helltown, USA)
Centralia, Pennsylvania
 (almost abandoned)
Centralia, Pennsylvania
     (Highway 61)
Acid Mine Drainage
*results when the mineral pyrite (FeS2) is exposed to air and water, resulting in the formation of sulfuric acid and iron hydroxide
Slurry Pond Spill in Kentucky
        October 2000
Surface Mining Control & Reclamation
             Act of 1977
                  •   Came about due to concerns
                      about damage from strip
                      mining
                  •   Regulates active mines and
                      drives reclamation
                  •   Requires permits for mining
                  •   Allows for inspection and
                      punishment
                  •   Requires companies post a
                      bond before mining to
                      ensure cleanup is done
                  •   Prohibits strip mines in
                      National Parks
Reclamation




Restoration of abandoned
surface coal mine in Pennsylvania-
now wild game lands
Sources for You to Explore
•   http://www.xydexx.com/modernruins/centralia_galle
•   http://www.mountainjusticesummer.org/facts/steps.
•   http://www.mii.org/reclcoal.html
•   http://www.blm.gov/education/00_resources/articles
•   http://www.wma-minelife.com/coal/coalhome.html

Mining Practices 2012