mining practices & impacts

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Mining Practices and Impacts Derrick Willard

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

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Page 1: Mining Practices & Impacts

Mining Practices and Impacts

Derrick Willard

Page 2: Mining Practices & Impacts

Why do we mine minerals?

Page 3: Mining Practices & Impacts

Coal Types & Uses

Page 4: Mining Practices & Impacts

Coal Found in 32 States

Valued for energy and steel production

Page 5: Mining Practices & Impacts

Identifying Mineral Deposits (costs $$$$$ to find them…)

• Aerial photos• Radiation detectors• Magnetometer• Gravimeter• Deep well drilling• Seismic survey• Chemical analysis

Page 6: Mining Practices & Impacts

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

Page 7: Mining Practices & Impacts

Q. Just how much land are we talking about?

A. About 270 million acres (or 1/4 of USA)

Page 8: Mining Practices & Impacts

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

Page 9: Mining Practices & Impacts

Methods of Coal Mining

Page 10: Mining Practices & Impacts

US Mining Trends

Page 11: Mining Practices & Impacts

Pros and ConsSurface 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

Page 12: Mining Practices & Impacts

Surface Mining

• Strip out overburden (becomes spoils)• Four land methods possible

– Open-pit (quarry)– Area strip mining (flat terrain)– Contour strip mining (hilly terrain)– Mountaintop removal

• Clean up (reclamation)

Page 13: Mining Practices & Impacts

Overburden Removal

Page 14: Mining Practices & Impacts

A Dragline Shovel

Page 15: Mining Practices & Impacts

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...

Page 16: Mining Practices & Impacts

Open Pit Copper Mine near Silver City, NM

Page 17: Mining Practices & Impacts

Area Strip Mining

Page 18: Mining Practices & Impacts

Area Strip Mine (Coal)

Page 19: Mining Practices & Impacts

Contour (Bench) Strip Mining

Page 20: Mining Practices & Impacts

Contour Mining in KY“Highwalls”

Page 21: Mining Practices & Impacts

The “New” Technique

Page 22: Mining Practices & Impacts

Mountaintop Removal Mining

Page 23: Mining Practices & Impacts

Mountaintop Removal and Valley Fill (WV)

The top of a mountain has been pushed into a valley

Page 24: Mining Practices & Impacts

Mountaintop Removal Coal Mine in Southern WV

Page 25: Mining Practices & Impacts

Mountaintop(s) Removal near Kayford Mountain, WV

Page 26: Mining Practices & Impacts

Mountaintop Removal-Up Close (spoil pile)

Page 27: Mining Practices & Impacts

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)

Page 28: Mining Practices & Impacts

Subsurface Mine Types

Page 29: Mining Practices & Impacts

Longwall Mining

Page 30: Mining Practices & Impacts

Longwall Mining Machine

Page 31: Mining Practices & Impacts

Room and Pillar Mining

Page 32: Mining Practices & Impacts

Room and Pillar Mining

Page 33: Mining Practices & Impacts

Room and Pillar Mining Machine

Page 34: Mining Practices & Impacts

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.

Page 35: Mining Practices & Impacts

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

Page 36: Mining Practices & Impacts

Scarring in Tennessee

Page 37: Mining Practices & Impacts

Subsidence over a Coal Shaft in Colorado

Page 38: Mining Practices & Impacts

Coal Mine Subsidence in Colorado

Page 39: Mining Practices & Impacts

Centralia, Pennsylvania (where a coal vein fire started in 1961)

Page 40: Mining Practices & Impacts

Centralia, Pennsylvania (Helltown, USA)

Page 41: Mining Practices & Impacts

Centralia, Pennsylvania (almost abandoned)

Page 42: Mining Practices & Impacts

Centralia, Pennsylvania (Highway 61)

Page 43: Mining Practices & Impacts

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

Page 44: Mining Practices & Impacts

Slurry Pond Spill in KentuckyOctober 2000

Page 45: Mining Practices & Impacts

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

Page 46: Mining Practices & Impacts

Reclamation

Restoration of abandonedsurface coal mine in Pennsylvania-now wild game lands