Geology and Nonrenewable Minerals

1
Geology and Nonrenewable Minerals

• Chapter 14

PART 1
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GEOLOGIC TIMESCALE

• Geologists have divided Earth's history into a
  series of time intervals.
• The geologic time scale was constructed to
  visually show the duration of each time unit.

• The Earth is 4.6 billion years old.
• The geologic processes have been happening for a
  very long time.
• Humans just showed up at the end.

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GEOLOGIC TIMESCALE

• The time intervals are variable in length. This
  is because geologic time is divided using
  significant events in the history of the Earth.
• New biological developments
• Mass extinctions

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14-1 What Are the Earths Major Geological
Processes and Hazards?

• Concept 14-1A Gigantic plates in the earths
  crust move very slowly atop the planets mantle,
  and wind and water move the matter from place to
  place across the earths surface.
• Concept 14-1B Natural geological hazards such as
  earthquakes, tsunamis, volcanoes, and landslides
  can cause considerable damage.

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The Earth Is a Dynamic Planet

• The earths interior consists of
• Core innermost zone with solid inner core and
  molten outer core that is extremely hot
• Mantle liquid rock with a rigid outer part
  (asthenosphere) that is melted pliable rock
• Crust layer of solid rock (lithosphere) which
  underlies the continents and the oceans
• Continental crust
• Oceanic crust

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The Earth Beneath Your Feet is Moving

• Plate Tectonics
• The theory that Earths crust is divided into
  huge tectonic plates that float on magma or
  molten rock.
• Convection currents within the mantle move the
  plates around.
• Evidence
• Puzzle-like fit of the continents
• Matching plant/animal fossils on
  opposite sides of oceans
• Matching rock layers on opposite
  sides of oceans
• Evidence of past climates

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The Earths Major Tectonic Plates
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Major Features of the Earths Crust and Upper
Mantle

• Major features of the earths crust and upper
  mantle.

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Tectonic Plate Boundaries

• Plates move apart at divergent plate boundaries.

• Mid-ocean ridge the site of sea-floor spreading

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Tectonic Plate Boundaries

• Plates grind into one another at convergent plate
  boundaries.
• Folded mountains
• Volcanic mountains

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Tectonic Plate Boundaries

• Plates slide past one another at transform plate
  boundaries.

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Some Parts of the Earths Surface Build Up and
Some Wear Down

• Internal geologic processes
• Generally build up the earths surface
• Result from the heat generated by the Earths
  interior
• External geologic processes
• Wear down the Earths surface and move it around
• Result from solar energy and gravity (wind,
  flowing water)

• Weathering Processes that break rocks down into
  smaller pieces
• Plays key role in soil formation
• Different kinds of rock will result in different
  soil properties

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Volcanoes Release Molten Rock from the Earths
Interior

• Volcanoes are simply vents in the earth's surface
  through which lava and other volcanic products
  erupt.

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Earthquakes Are Geological Rock-and-Roll Events

• The sudden release of energy stored up by the
  movement of tectonic plates

• Energy travels as seismic waves, each with own
  type of movement and speed.
• P-wave
• S-wave
• Surface
• waves

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14-2 How Are the Earths Rocks Recycled?

• Concept 14-2 The three major types of rocks
  found in the earths crustsedimentary, igneous,
  and metamorphicare recycled very slowly by the
  process of erosion, melting, and metamorphism.

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There Are Three Major Types of Rocks

• A very slow geochemical cycle involves three
  types of rock found in the earths crust
• Igneous rock (granite, pumice, basalt)
• Solidified lava or magma
• Sedimentary rock (sandstone, limestone, shale)
• Fusion of eroded sediments
• Metamorphic rock (slate, marble, quartzite)
• Application of heat / pressure

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Natural Capital The Rock Cycle Is the Slowest of
the Earths Cyclic Processes
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14-3 What Are Mineral Resources, and what are
their Environmental Effects?

• Concept 14-3A Some naturally occurring materials
  in the earths crust can be extracted and made
  into useful products in processes that provide
  economic benefits and jobs.
• Concept 14-3B Extracting and using mineral
  resources can disturb the land, erode soils,
  produce large amounts of solid waste, and pollute
  the air, water, and soil.

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We Use a Variety of Nonrenewable Mineral
Resources

• Mineral naturally occurring, inorganic, solid
  element or compound with a definite chemical
  composition and a regular internal crystal
  structure.
• Mineral resource (Ore) a deposit of minerals
  that can be extracted and processed into useful
  materials at an affordable cost.
• Deposits of nonrenewable mineral resources in the
  earths crust vary in their abundance and
  distribution.
• High Grade Ore high percentage of desired
  mineral
• Low Grade Ore low percentage of desired mineral

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We Use a Variety of Nonrenewable Mineral
Resources

• Examples of nonrenewable metal and nonmetal
  mineral resources
• Aluminum beverage cans, motor vehicles,
  aircraft
• Steel (alloy of iron and other elements)
  buildings
• Copper electrical and communications wiring
• Platinum electrical equipment, industrial
  catalyst
• Gold electrical equipment, jewelry, medical
  implants
• Sand glass, bricks, concrete
• Limestone, - road rock, concrete, cement
• Manganese, Cobalt, Chromium light bulbs,
  computers, automobiles, aircraft, etc.

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Concentration of Minerals in Earths Crust
Aluminum 8 Iron 5.8 most Fe
and Al is in silicate minerals (like sand) and
is, therefore, not used as an
ore Titanium 0.82 Nickel 0.0075 Zinc
0.0082 Copper 0.0058 Lead
0.0013 Uranium 0.00016 Silver
0.000008 Gold 0.0000004
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Classification of Nonrenewable Mineral Resources

• The U.S. Geological Survey classifies mineral
  resources into four major categories
• Identified location, quantity, and quality or
  existence known based on direct evidence and
  measurements.
• Undiscovered potential supplies that are assumed
  to exist.
• Reserves identified resources that can be
  extracted profitably.
• Other undiscovered or identified resources not
  classified as reserves

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The Life Cycle of a Metal Resource

• The extraction, processing, and use of mineral
  resources has a large environmental impact.
• Mining of low grade ore requires more energy,
  water, and produces more waste.

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Extracting, Processing, Using Nonrenewable
Mineral and Energy Resources
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Geology and Nonrenewable Minerals

• Chapter 14

PART 2
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There Are Several Ways to Remove Mineral
Deposits

• Minerals are removed through methods that vary
  widely in their costs, safety factors, and levels
  of environmental harm.
• The method used is based on mineral depth
• Surface mining shallow deposits are removed
• Open pit mining
• Strip mining
• Subsurface mining deep deposits are removed
• Underground shafts and/or tunnels

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There Are Several Ways to Remove Mineral
DepositsSurface Mining

• Open Pit Mining
• Machines dig holes and remove ores, coal, sand,
  gravel, and stone.
• Toxic groundwater can accumulate at the bottom.

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There Are Several Ways to Remove Mineral
DepositsSurface Mining

• Strip Mining Area Strip Mining
• Earth movers strips away overburden in order to
  remove the mineral deposit.
• Often leaves highly erodible hills of rubble
  called spoil banks.
• When the ore is dredged from rivers or streams,
  the unused piles are called tailings.

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There Are Several Ways to Remove Mineral
DepositsSurface Mining

• Strip Mining Contour strip mining
• When mining hilly or mountainous terrain
• Terraces are created
• As workers move up the slope, the spoils are
  dumped on the terrace below

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There Are Several Ways to Remove Mineral
DepositsSurface Mining

• Sometimes whole mountain tops are stripped away
  to get to the ore below Mountain-top removal
• This is a common practice for coal mining in
  Appalachian mountains

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There Are Several Ways to Remove Mineral
DepositsSubsurface Mining

• Subsurface mining shafts and tunnels are used
  to get to ore that is buried much deeper below
  the surface.
• A variety of configurations are used, depending
  on the situation.

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There Are Several Ways to Remove Mineral Deposits

• Surface mining
• Cheap
• Safe for miners
• Large environmental destruction
• Subsurface mining
• Expensive
• Hazardous for miners
• Less environmental damage

Mining Animation/Virtual Tour http//www2.illinoi
sbiz.biz/coal/virtualtour/index.html
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Mining Has Harmful Environmental Effects

• Scarring and disruption of the land surface
• Piles of mine spoils and tailings
• (99 of mined material is waste material)
• Subsidence
• Loss of rivers and streams
• Disruption of ground water flow patterns
• Acid Mine Drainage - sulfuric acid produced
  through weathering of iron sulfide in tailings
• 4FeS2 14H2O 4Fe(OH)3 8H2SO4
• Major pollution of water and air
• Contamination from heavy metals in mine tailings
• e.g. arsenic, mercury

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Reclamation, or Ecological Restoration

• Reclamation an attempt to return mined land
  back to its original state (or at least a
  functional ecosystem)
• Recreation
• Commercial use

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Removing Metals from Ores Has Harmful
Environmental Effects

• Ore extracted by mining has two parts
• The Ore mineral which is the desired metal
• The Gangue (gang), or waste material
• Smelting heating ore to release the metal
• Chemical solvents can be used as well

• Huge amounts of air and water pollution is
  produced
• Contaminated water or toxic sludge sits around in
  large pools or lagoons

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14-4 How Long Will Supplies of Nonrenewable
Mineral Resources Last?

• Concept 14-4A All nonrenewable mineral resources
  exist in finite amounts, and as we get closer to
  depleting any mineral resource, the environmental
  impacts of extracting it generally become more
  harmful.
• Concept 14-4B An increase in the price of a
  scarce mineral resource can lead to increased
  supplies and more efficient use of the mineral,
  but there are limits to this effect.

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Mineral Resources Are Distributed Unevenly

• Most of the nonrenewable mineral resources are
  supplied by the United States, Canada, Russia,
  South Africa, and Australia
• The United States, Germany, and Russia (8 of the
  worlds population) consume about 75 of the
  worlds widely used metals.
• Strategic metal resources minerals essential
  for a countrys economic and military strength
• Manganese, Cobalt, Chromium, and Platinum
• The U.S. has little or no reserves of these
  metals

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Supplies of Nonrenewable Mineral Resources Can Be
Economically Depleted

• Future supply depends on
• Actual or potential supply of the mineral
• Rate at which it is used
• A rising price for a scarce mineral resource can
  increase supplies and encourage more efficient
  use.
• Aluminum
• Gold
• When it becomes economically depleted costs
  more to extract/process a mineral than what its
  worth
• Recycle or reuse existing supplies, waste less,
  use less, find a substitute, do without

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Natural Capital Depletion Depletion Curves for
a Nonrenewable Resource

• Depletion time - The time it takes to use up a
  certain proportion (usually 80) of the mineral
  reserves at a given rate of use
• Dashed vertical lines represent times when 80
  depletion occurs.

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Mining Legislation

• U.S. General Mining Law of 1872
• Encouraged mineral exploration and mining of
  hard-rock minerals (gold, silver, copper, nickel)
  on U.S. public lands
• Developed to encourage settling the West (1800s)
• Until 1995, land could be bought for 1872 prices
• Estimated 285 billion of mineral resources now
  owned/ controlled by private companies, 1/5 are
  foreign.
• Surface Mining Control and Reclamation Act of
  1977
• Requires the reclamation of land surfaced mined
  for coal. There are no laws to control or reclaim
  lands from other types of mines, like hard-rock,
  etc.

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14-5 How Can We Use Mineral Resources More
Sustainability?

• Concept 14-5 We can try to find substitutes for
  scarce resources, reduce resource waste, and
  recycle and reuse minerals.

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Solutions Sustainable Use of Nonrenewable
Minerals