GEOLOGY and MINERAL RESOURCES

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GEOLOGY and MINERAL RESOURCES
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Geologic Processes Structure of the Earth
Fig. 4-7 p. 60
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Major Rock Groups

• Igneous
• Formed from a melt (molten rock)
• Plutonic (intrusive)slow cooling and
  crystallization
• Volcanic (extrusion) quick cooling at the
  surface
• Sedimentary
• Formed at the Earths surface
• Metamorphic
• Changed by pressure, temperature and fluids.

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Fig. 2.9
MAGMA
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IGNEOUS
Crystallization
MAGMA
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IGNEOUS Plutonic
Crystallization
MAGMA
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Volcanic IGNEOUS Plutonic
Crystallization
MAGMA
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Weathering
Volcanic IGNEOUS Plutonic
Crystallization
MAGMA
Uplift
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External Earth Processes

• Erosion (wind, water, gravity)

• Mechanical weathering

• Frost wedging

• Chemical weathering (precipitation
• Moisture)

• Biological weathering (root wedging,
• borrowing)

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SEDIMENT
SEDIMENT
Weathering
Volcanic IGNEOUS Plutonic
Crystallization
MAGMA
Uplift
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Erosion
SEDIMENT
Weathering
Transport
Deposition
Volcanic IGNEOUS Plutonic
SEDIMENTARY
Crystallization
MAGMA
Uplift
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Erosion
SEDIMENT
Weathering
Transport
Deposition
Volcanic IGNEOUS Plutonic
SEDIMENTARY
Crystallization
MAGMA
Uplift
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Erosion
SEDIMENT
Weathering
Transport
Deposition
Volcanic IGNEOUS Plutonic
SEDIMENTARY
Increased PT
METAMORPHIC
Crystallization
Burial
MAGMA
Uplift
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Erosion
SEDIMENT
Weathering
Transport
Deposition
Volcanic IGNEOUS Plutonic
Can you see any shortcuts?
SEDIMENTARY
Increased PT
METAMORPHIC
Crystallization
Melting
Burial
MAGMA
Uplift
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Erosion
SEDIMENT
Weathering
Transport
Deposition
Volcanic IGNEOUS Plutonic
SEDIMENTARY
Increased PT
METAMORPHIC
Crystallization
Melting
Burial
MAGMA
Uplift
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In Conclusion

• The rock cycle demonstrates the relationships
  among the three major rock groups
• It is powered by the interior heat of the Earth
• The energy from the sun
• It involves processes on the Earths surface as
  well as the Earths interior.

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Features of the Crust and Upper Mantle
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Plate Tectonics

• Divergent boundary

• Convergent boundary

• Subduction zone

• Transform fault

Fig. 16-5 p. 336
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Divergent Boundaries

• Spreading ridges
• As plates move apart new material is erupted to
  fill the gap

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Iceland An example of continental rifting

• Iceland has a divergent plate boundary running
  through its middle

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Convergent Boundaries

• There are three styles of convergent plate
  boundaries
• Continent-continent collision
• Continent-oceanic crust collision
• Ocean-ocean collision

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Continent-Continent Collision

• Forms mountains, e.g. European Alps, Himalayas

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Himalayas
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Continent-Oceanic Crust Collision

• Called SUBDUCTION
• Area is called the subduction zone

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Transform Boundaries

• Where plates slide past each other

Above View of the San Andreas transform fault
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Earths Major Tectonic Plates
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Natural Hazards Earthquakes

• Features

• Magnitude

• Aftershocks

• Primary effects

• Secondary effects

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Expected Earthquake Damage
Fig. 16-7 p. 337
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Natural Hazards Volcanic Eruptions
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Volcanic Eruptions

• Pyroclastic Flow cloud of ash and debris
• Travel at hundreds of mph
• Hundreds of degrees

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Volcanic Eruptions

• Lahar mud flows which are very destructive to
  landscape

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Volcanic Eruptions
http//www.youtube.com/watch?vUK--hvgP2uY

• Ash emitted includes small stones
• Very dense
• Chokes life
• Blots out sunlight
• Causes wide range temperature drops

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Tsunami

• Harbor Wave

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Nonrenewable Resource

• Resource that exists in a fixed amount in various
  places in the Earths crust and has the potential
  for renewal only by geological, physical and
  chemical processes taking place over hundreds of
  millions of years.
• Mineral Resources naturally occurring,
  inorganic solid in or on the earths crust that
  can be extracted and processed into useful
  materials at an affordable cost.

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Nonrenewable Mineral Resources

• Metallic ores (Fe, Cu, Al)

• Non-metallic (salt, gypsum,
• clay, sand, PO4)

• Energy resources (coal, radioactive isoptopes,
  oil, natural gas) typically not mineral
  resources

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Nonrenewable Mineral Resources USGS Categories

• Identified
• know location,
• quality and quantity

• Undiscovered -
• inferred

• Reserves -
• known location,
• affordable extraction

• Other -identified/
• undiscovered but NOT reserved

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Finding Nonrenewable Mineral Resources

• Satellite and air imagery

• Radiation detectors

• Magnetometers

• Gravity differences

• Seismic surveys

• Chemical analyses

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Extracting Nonrenewable Mineral Resources

• Open-pit (surface mining)

• Dredging (surface mining)

• Area strip (surface mining)

• Contour strip (surface mining)

• Room-and-pillar (subsurface mining)

• Longwall (subsurface mining)

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Open Pit Mining (surface)

• Machines remove mineral resource.

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Dredging (surface)

• Dig underwater mineral deposits

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Area Strip Mining (surface)

• Strip mining in flat landscape areas.

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Contour Strip Mining (surface)

• Creation of terraces along contour elevations
  where overburden is removed and a high wall is
  created which is very erodable.

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Mountaintop Removal

• Dragline cuts the top of the mountain off and
  dumps it into the surrounding valley.

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Room and Pillar (subsurface)

• This method creates shafts dug below the surface
  that are then blasted with dynamite to create
  tunnels. The ore/coal can then be hauled to the
  surface.

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Room Pillar Method
Room and pillar mining is commonly done in flat
or gently dipping bedded ores. Pillars are left
in place in a regular pattern while the rooms are
mined out. In many room and pillar mines, the
pillars are taken out, starting at the farthest
point from the mine haulage exit, retreating, and
letting the roof come down upon the floor. Room
and pillar methods are well adapted to
mechanization, and are used in deposits such as
coal, potash, phosphate, salt, oil, shale, and
bedded uranium ores.
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Longwall (subsurface)

• Dig a narrow tunnel supported by removable
  pillars. The benefit is that no tunnels are left
  behind to collapse once abandoned.

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Subsurface vs. Surface Mining

• Subsurface mining is less environmentally
  destructive than surface mining BUT
• Subsurface mining is more dangerous to workers.
  Walls collapse, explosions from gas, inhalation
  of mining dust leads to black lung

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U.S. 1872 Mining Law

• Encourages mining in the USA for gold, silver,
  lead, copper, uranium, and hard rock minerals.
• People OR Corporations can patent public land by
• a. Declaring it has valuable minerals
• b. Spending 500 to improve land for mineral
  development
• c. Filing a claim for the land
• d. Pay US Government 2-5/acre!
• MINERALS NEVER NEED TO BE EXTRACTED
• Can sell land to extraction companies for
  millions of dollars (usually foreign companies)
  who pay no royalties to US Government.

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Colorado Case Study

• Canadian Company bought a site for a few thousand
  dollars.
• They spent 1 million dollars developing the site,
  removed 98 million dollars worth of gold.
• Acid mine drainage leached into the Alamusa
  River.
• Company declared bankruptcy and abandoned the
  site leaving the EPA Superfund to pay for clean
  up ( taxpayer money)
• Costs 40,000/day to contain toxic waste
• Also contaminates irrigation water (no way to
  clean up)

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USA 1872 Mining Law Continued

• If public land is designated as valuable
  wilderness area, the government can buy back the
  land (our tax ) at market value.
• Any lands mined do not have to be reclaimed.
  They can be left in highly erodable states with
  leaching toxins into air, water, and soil.

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Mining Company Practices

• Companies will usually
• Mine land
• Abandon the land
• File for bankruptcy
• Leave taxpayers with cleanup bill (33-72 billion
  dollars per year!
• Superfund sites (Super funds that the EPA
  designates to be used for hazardous waste
  cleanup)
• If groundwater becomes contaminated, it cant be
  cleaned up and there is no way of estimated the
  cost to humans!

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Should the mining law of 1872 be changed?

• Environmentalists propose amendments to the law
• Lease land for 20 years instead of buying it.
• Conduct full NEPA Environmental Assessment of
  impacts before mining begins.
• Set strict standards for controlling pollution
  and protecting environment from toxins and
  erosion.
• Company should post environmental insurance bond
  to cover estimated environmental damage and clean
  up costs in the future.
• Companies should pay rent to cover costs for
  government monitoring of lands.
• 12.5 royalty should be paid to government on
  gross sales. Mining companies claim that
  charging royalties and forcing them to clean up
  their mess will not make it economically feasible
  to mine in USA anymore. This will lead to a
  decrease in jobs for Americans.
  Environmentalists claim mining companies will
  still make profits, just not as much!
• Make mining companies legally and financially
  responsible for clean up.

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Surface Mining Control and Reclamation Act

• Established 1977

• Mine lands must be restored to pre-mining
  conditions

• Taxes on mining companies to restore pre-1977
  sites

• Limited success

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Environmental Effects of Mining Mineral Resources

• Disruption of land surface

• Subsidence

• Erosion of solid mining waste

• Acid mine drainage

• Air pollution

• Storage and leakage of liquid mining waste

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Environmental Degradation From Processing of
Minerals

• Processing includes transportation, purification,
  and manufacturing of minerals
• Smelting impacts air, water, and soil What goes
  up must come back down

Smelting
desired ore
Gange (waste)
Beneficiation separation of additional ore from
gange
Ore
Tailings (toxic metals)
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Environmental Impacts

• Air and noise pollution
• Dust created by mining and loading/unloading
• Machine causes noise pollution and damage nearby
  structures

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Environmental Impacts

• Water Contamination
• Water picks up and dissolves toxic substances
  (arsenic)
• Sulfur and water diluted sulfuric acid
• Acid Mine Drainage - AMD

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Environmental Impacts

• Mountain Dew Teeth

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Environmental Impacts

• Displacement of Wildlife
• Stripping of plant life
• Animals leave area
• New ecosystem created after
• Destroy river and sea bottoms

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Environmental Impacts

• Erosion and Sedimentation
• Sediments find way into streams
• Choke stream life
• Degrades water quality

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Environmental Impacts

• Soil Degradation
• Deeper soil layers added to top
• Decreases richness of original soil
• Subsidence (sink holes)
• Sinking of regions of ground with no horizontal
  movement

http//www.theblaze.com/stories/2013/03/01/man-goe
s-missing-in-florida-when-bedroom-falls-into-sinkh
ole/
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Environmental Impacts

• Underground Mine Fires
• Last decades and even centuries
• Australian fire 2,000 Years!!!!!
• Gas and smoke emitted

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Smelting Copper

• Cu Sox soot (SO2) As Cd Pb

Scrubbers and electrostatic precipitators are
expensive technology that help to remove the
harmful substances before being released into the
atmosphere.
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Environmental Degradation From End-Use

• Transportation to user, final use, and discarding
  after use.
• Fossil fuels are burned during transportation of
  end product.
• Product must be discarded in
• 1. landfill where metals corrode and pollute
  land and water.
• 2. Recycle and reuse (In USA, most goes to
  landfill, but recycling of solid waste is
  improving each year.

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Environmental Effects of Mining Mineral Resources
Fig. 16-14 p. 344
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More Environmental Impacts of Nonrenewable
Mineral Resources
Surface mining
Subsurface mining

• Overburden

• Room and pillar

• Spoil

• Longwall

• Open-pit

• Dredging

Refer to Figs. 15-4 and 15-5, p. 341 and 342

• Strip mining

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Processing Mineral Resources

• Ore mineral what is wanted

• Gangue waste around ore

• Tailings - leftover

• Smelting process to remove

Refer to Fig. 16-15 p. 344
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Supplies of Non-Renewable Resources

• Dependent on
• (a) actual or potential supplies
• (b) rate of use
• Minerals become economically depleted when the
  cost of extraction is greater that the profit.
• What de we do? We have choices
• (a) refuse, reduce, reuse, recycle
• (b) find substitute

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Depletion of Mineral Resources
Depletion Time the time it takes to use up a
certain proportion (80) of the reserves of a
mineral at a given rate.
Common Projection Rate Reserve to Production
Ratio the number of years that proven reserves
of a particular non-renewable resource will last
at a current production rate.
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Economics of Mineral Resources

• Free Market when supply is greater than demand
  cheap costs to consumers.

• Definition a market in which supply and demand
  are unregulated except by the country's
  competition policy, and rights in physical and
  intellectual property are upheld.
• In a free market there are
• Fulfillment the process of responding to
  customer inquiries, orders, or sales promotion
  offers.
• Future a contract to deliver a commodity at a
  future date.
• Futures market a market for buying and selling
  securities, commodities, or currencies that tend
  to fluctuate in price over a period of time.

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Why are items made of Zn, Pb, Hg, Fe, and Al so
cheap, if their depletion times are nearing?

• Fe/Al 100 years in world reserves.
• Hg/Zn/Pb 20 years in world reserves.
• Subsidies to promote economic growth and
  national security. Is there really a free
  market?
• Harmful environmental costs of mining and
  processing are not included in their market
  price. NO TRUE COSTING!
• Ore grades have been lowered. Example 1900 Cu
  penny 5 by weight, now 0.5 by weight. Ask
  yourselfare reserve to ration production numbers
  real?
• As technology improves we learn more about where
  more minerals may be on Earth and dont have to
  impart tremendous damage to landforms during
  exploration activities.

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Global Non-Fuel Minerals

• Mostly in the USA, Canada, Australia, South
  Africa, and the Republics of the former Soviet
  Union.
• Western Europe depends mostly on minerals from
  Africa.
• USA imports 24 of the 42 most important non-fuel
  minerals.
• Concerns manganese, cobalt, platinum, and
  chromium USA has little or no reserves and we
  get them from unstable African nations.
• USA uses these minerals for autos, airplanes,
  engines, satellites, and sophisticated weapons!