Post on 14-Dec-2015
Minerals• Concentration of
naturally occurring elements in/on Earth.
• Formed over millions of yrs non-renewable resource.
What We Mine?!? • Metallic minerals: Iron, Copper, Aluminum
• Non-metallic minerals: salt, clay, sand
• Energy minerals: coal, oil, uranium
Crushed Iron Sodium Chloride Crystal “Dur”rty Coal
Ore• Rock that has
metallic mineral.
• Usable stuff is the mineral
• Non-usable is called gangue landfill
Gold
Gangue
Finding Mineral Deposits
• Use planes w/ Geiger meter (uranium) or magnetometer (iron)
Geiger Meter…Only $460!
Magnetometer… Only $700!
Surface Mining
• Minerals must be shallowly deposited.
• Removed rock and soil is called overburden or spoil.
Area Strip Mining
• Cut new strips away; spoil placed on side, mineral taken out.
Types of Surface Mining
Mountaintop Removal
• Use TNT, huge shovels, and large machines to remove top of a mtn and expose coal
underneath.
Types of Surface Mining
Case Study Gold: Cyanide Heap Leaching
• Cyanide sprayed on low grade gold ore in a giant heap (pile).
• Gold flows down w/ cyanide and is collected at bottom of heap.
Heap
Case Study Gold: Cyanide Heap Leaching
• Toxic to birds and mammals.
• Leach ponds can overflow H2O pollution
• Leaky liners?Leach Liner
Types of Subsurface Mining
• Room and Pillar
• Machines are used to cut out minerals and are placed on a shuttle car.
Scraper
• Longwall Coal Mining
• Moveable steel props support cave while machinery cut off coal onto a conveyor belt.
Types of Subsurface Mining
• Collapse/subsidence of land from subsurface mines.
• Causes houses to tilt, sewer lines crack, gas mains break.
Environmental Damage
• Wind/water carry away [by erosion] toxic mining waste.
• Goes in food webs and watersheds.
Environmental Damage
Acid mine drainage• Bacteria eat FeS in spoil create
H2SO4 runs off into streams
Environmental Damage