Mining and Mineral Resources

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Mining and Mineral Resources

• Chapter 16
• Environmental Science

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Essential Questions

• Why are resources limited?
• How can we improve the efficiency of resource
  utilization?
• Why are decision-making bodies slow to respond to
  global resource issues?
• How does human resource use affect the
  environment?

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Minerals and Mineral Resources

• Objectives
• 1. Define the term mineral.
• 2. Explain the difference between a metal and a
  nonmetal, and give two examples of each.
• 3. Describe three processes by which ore minerals
  form.

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• A lot of what you use comes from minerals
• Minerals are mined from the ground in various
  ways and can harm the environment
• Resources will not last indefinitely

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• What is a mineral?
• A naturally occurring, usually inorganic solid
  that has a characteristic chemical composition,
  and orderly internal structure, and a
  characteristic set of physical properties

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• Atoms are arranged in regular, repeating patterns
• Most are compounds but some exist as native
  compounds (gold, silver, copper, )

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• Table 1. Average Composition of the Crust
• Element (Symbol) Weight percent
• Oxygen (O) 46.6
• Silicon (Si) 27.8
• Aluminum (Al) 8.1
• Iron (Fe) 5.0
• Calcium (Ca) 3.6
• Sodium (Na) 2.8
• Potassium (K) 2.6
• Magnesium (Mg) 2.1
• Total 98.5

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• Ore Minerals
• Minerals that are valuable and economical to
  extract
• Mining process removes the valuable minerals and
  the gangue (no commercial value) from the host
  rock

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Common Elements and Their Ore Minerals
Aluminum Gibbsite, boehmite, bauxite
Beryllium Beryl
Chromium Chromite
Copper Bornite, cuprite, chalcocie, chalcoprite
Iron Goethite, hematite, magnetite, siderite
Lead Galena
Manganese Psilomelane, pyrolusite
Mercury Cinnabar
Molybdenum Molybdenite
Nickel Pentlandite
Silver Acanthite
Tin Cassiterite
Titanium Ilmenite, rutile
Uranium Carnotite, urainite
Zinc sphalerite
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• Types of Minerals
• Metallic
• Conduct electricity, shiny, opaque
• Nonmetallic
• Good insulators, shiny or dull surfaces, and
  transparent or translucent

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• Mineral Formation
• Depends on the environment determine type of
  mineral
• Metallic min. form below ground when magna cools
  and hardens

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• Hydrothermal Solution. Hot, underground water
  flows through cracks in rocks, dissolving
  minerals they come in contact minerals
  crystallize out and fill cracks. Deposits become
  veins

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• Evaporites. Rivers and streams dissolve salts
  and carry them to seas and lakes. When the water
  evaporates the salt is left behind. Can form
  halite and gypsum.

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Uses of important Metallic and Nonmetallic
Elements
Al Cans, foil, windows, doors, siding, autos, aircraft
Cu Cables, wires, electrical, plumbing, coins
Au Computers, communication, spacecraft, dentistry, jewelry
Fe Steel
Lead Batteries, ammunition, glass, ceramics
Si Computer chips, glass, ceramics
Ag Photography, electrical, mirrors, chemistry
Su Sulfuric acid, gun powder, rubber
Ti Jet engines, aircraft, spacecraft, missiles, pigments
Zn Steel coatings, brass, rubber, paints
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Mineral Exploration and Mining

• Objectives
• 1. Describe the manner in which mining companies
  explore for new mineral deposits.
• 2. Describe three methods of subsurface mining.
• 3. Describe two methods of surface mining.
• 4. Define placer deposit, and explain how placer
  deposits form.
• 5. Describe the steps that take place in smelting
  an ore.

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• Mineral Exploration
• Mining companies wont mine unless the mineral
  deposit is 100-1000x the concentration of the
  ordinary rock

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How do they discover mineral deposits?

• Use instruments that identify gravity, magnetism,
  radioactivity
• Aircraft, satellites, aerial photos

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• Types of Mining
• Subsurface mining mining 50 m or more below the
  surface
• Longwall mining- uses a rotating shearer to
  remove mineral

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Rotating shear longwall mining
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• Solution mining hot water is injected into the
  ore and dissolves it

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Solution mining

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• Surface Mining
• Open pit mining
• Surface coal mining
• Quarrying
• Solar evaporation

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Surface mining
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Quarrying

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• Placer Mining
• Surface deposits concentrated by wind and water
• Along coastlines
• Mined by dredging
• Undersea Mining

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Placer mining Smelting

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• Smelting
• Crushed ore is melted at high temperatures in
  furnace to separate impurities from molten rock

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Mining Regulations and Mine Reclamation

• Objectives
• 1. Describe seven important potential
  environmental consequences of mining.
• 2. Name four federal laws that relate to mining
  and reclaiming mined land.
• 3. Define the term reclamation.
• 4. Describe two ways in which state governments
  regulate mining.

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• Environmental Impacts or consequences of Mining
• Air and noise pollution
• Water contamination
• Acid mine drainage when oxygen and water react
  with minerals to form sulfuric acid

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• Erosion and sedimentation
• Soil degradation
• Acidified soil
• Subsidence
• Underground mine fires

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• Mining Regulations and Reclamation
• Mines are regulated by state and federal laws
• Clean Water Act
• Comprehensive Response Compensation and Liability
  Act
• Endangered Species Act

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• Reclamation the process of returning land to
  original or better condition after mining is
  completed
• Surface Mining Control and Reclamation Act of
  1977
• State Regulation of Mining
• Permits Inspections