Unit 4: Earth

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Unit 4 Earths Resources

• Environmental Science

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NONRENEWABLE RESOURCES

• A nonrenewable resource is a natural resource
  that cannot be re-made or re-grown at a scale
  comparable to its consumption.

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COAL, PETROLEUM, AND GAS

• Coal, petroleum, and natural gas are considered
  nonrenewable because they can not be replenished
  in a short period of time. These are called
  fossil fuels.

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HOW IS COAL MADE ???
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HOW ARE OIL AND GAS MADE ???
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WHAT WAS THE DIFFERENCE BETWEEN COAL AND OIL/GAS?
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NUCLEAR ENERGY

• Nuclear fission uses uranium to create energy.
• Nuclear energy is a nonrenewable resource because
  once the uranium is used, it is gone!

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RENEWABLE RESOURCES

• Renewable resources are natural resources that
  can be replenished in a short period of time.
• ? Solar ? Geothermal
• ? Wind ? Biomass
• ? Water

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SOLAR

• Energy from the sun.
• Why is energy from the sun renewable?

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GEOTHERMAL

• Energy from Earths heat.
• Why is energy from the heat of the Earth
  renewable?

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WIND

• Energy from the wind.
• Why is energy from the wind renewable?

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BIOMASS

• Energy from burning organic or living matter.
• Why is energy from biomass renewable?

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WATER or HYDROELECTRIC

• Energy from the flow of water.
• Why is energy of flowing water renewable?

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Metal Resources

• Biggest Users of Metals
• United States
• Japan
• Europe
• Biggest Producers
• South America
• South Africa
• Former Soviet Union .

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Metal Resources
Metal Uses
Iron Heavy machinery, steel production
Aluminum Packaging foods beverages, transportation, electronics
Manganese High-strength, high-resistant steel alloys
Copper Building construction, electric/electroni industry
Chromium High strength steel alloy
Nickel Chemical industry, steel alloys
Lead Leaded gasoline, car batteries, paint, ammunition
Silver Photography, electronics, jewelry
Gold Medical, aerospace, electronic use, money, jewelry
Platinum Automobile catalytic converters, electronics, medical uses, jewelry-
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Non-Metal Resources

• Sand gravel
• Uses brick concrete construction, paving,
  road filler, sandblasting, glass (high silica
  content sand)
• Limestone
• Uses concrete, road rock, building stone,
  pulverized to neutralize acidic soil or water.
• Evaporites- halite, gypsum, potash
• Uses halite- rock salt for roads, refined into
  table salt
• Gypsum- makes plaster wallboard
• Potash- for fertilizer (potassium chloride,
  potassium sulfates)
• Sulfur deposits
• Uses sulfuric acid in batteries some
  medicinal products

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Steps in Obtaining Mineral Commodities

1. Prospecting- finding places where ores occur
2. Mine exploration development- learn whether ore
   can be extracted economically
3. Mining- extract ore from ground
4. Beneficiation- separate ore minerals from other
   mined rock
5. Smelting refining- extract pure mineral from
   ore mineral (get the good stuff out of waste
   rock)
6. Transportation- carry mineral to market
7. Marketing sales- find buyers sell the mineral

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Types of Mining

• Surface- scoop ore off surface of the earth or
  dig big holes and scoop
• Cheap
• Safe for miners
• Large amount of environmental destruction
• Subsurface- use shafts to reach deeply buried
  ores
• Expensive
• Hazardous for miners
• Less environmental damage

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Types of Surface Mining

• 1. Open Pit Mining
• Overlaying material is removed using large
  equipment
• Creates pits that are hundreds of meters wide and
  hundreds of meters deep.

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Types of Surface Mining

• 2. Strip mining
• Like open pit but not as deep of a pit
• Same environmental damage

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Large bucket wheel extractor being moved through
Germany. Moves 10 meters per minute. Takes 5
people to operate. Used in strip mining
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Types of Surface Mining

• Dredging
• Sand is removed from bottom of ocean
• Can be done to restore beaches (after hurricane)
• Destroys fragile benthic ecosystems

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Types of Subsurface mining

• Underground Coal mining
• Shaft mine
• Slope mine
• Drift mine

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Types of Subsurface mining

• Room and Pillar mining
• Remove rock/ore from rooms and leave pillars for
  support.

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Types of Subsurface mining

• Longwall mining
• One long strip (wall) of coal is mined in a
  single strip (0.5 1.0 m at a time)

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Health Problems

• mine collapse
• fire (methane, coal dust, etc.).
• asphyxiation (methane, carbon monoxide)
• pneumoconiosis (from inhaling coal dust)
• asbestosis (from inhaling asbestos fibers)
• silicosis (from inhaling silicate dust)
• heavy metal poisoning (e.g. mercury)
• radiation exposure (in uranium mining)

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Environmental Damage

• Gaping holes in ground (old open pit mines)
• Accidental draining of rivers and lakes
• Disruption of ground water flow patterns
• Piles of gangue- mine tailings (mining waste)
• Loss of topsoil in strip-mined regions (350 to
  2,700 km2 in US alone)
• Spoil banks are where holes were filled in with
  waste- cheap easy- susceptible to erosion,
  chemical weathering, causes high sediment runoff
  in watersheds. Steep slopes are slow to
  re-vegetate (succession happens slowly- no
  topsoil)
• Contamination of soil or water from heavy metals
  (e.g. arsenic, mercury) in mine tailings.
• Contamination from sulfuric acid (H2SO4) produced
  through weathering of iron sulfide (FeS2, pyrite)
  in tailings.
• 4FeS2 14H2O 4Fe(OH)3 8H2SO4
• Water leaking into mine shafts, washes dissolved
  metals toxic material into water sources.
• (550,000 abandoned mines in U.S.- 12,000 mi of
  rivers streams contaminated with mine drainage-
  cost to clean up 32-72 billion)

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Acid Mine Drainage
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Acid Mine Drainage

• The impact of mine drainage on a lake after
  receiving effluent from an abandoned tailings
  impoundment for over 50 years

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Relatively fresh tailings in an impoundment.
http//www.earth.uwaterloo.ca/services/whaton/s06_
amd.html
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Mine effluent discharging from the bottom of a
waste rock pile (gangue)
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Shoreline of a pond receiving AMD showing massive
accumulation of iron hydroxides on the pond
bottom
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Surface Mining Control Reclamation Act (SMCRA)

• 1977
• Requires better restoration of strip-mined lands
• Restoration is difficult expensive
• Takes long time for soil to regain fertility
• Topsoil gets buried
• Compacted, poor drainage
• Root growth restricted
• Minimum cost- 1000 per acre
• Complete restoration (if possible)- 5,000 per
  acre

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History of Supplemental Energyin United States

• Wood through mid-1800s
• Renewable
• Maximum sustained yield limits supply

• Coal replaced wood by 1900

• Oil, natural gas exploited (since mid-1900s)
• 1-oil, 2-natural gas, 3-coal
• - all non-renewable

• Use growing dramatically

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100
Wood
Coal
80
Natural gas
60
Contribution to total energy consumption (percent)
Oil
40
Hydrogen Solar
20
Nuclear
0
2100
2025
1950
1875
1800
Year
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How long will supplies last?

• U.S. (5 pop) uses 25 of energy

• Depends on
• - rate of use
• - discovery of new supplies

• Resource supply lifetime
• - oil - 30-60 years
• - natural gas - 50-200 years
• - coal - 650-900 years

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North American Energy Resources
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Oil Shale and Tar Sands

• Oil shale
• 3X conventional

• Kerogen
• 25 gallons/ton
• Energy inenergy out

• Tar sands

• Bitumen
• 3X return on energy inputs

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Natural Gas

• 50-90 methane

• Propane, butane
• removed, liquified

• Cleanest burning,
• lowest costs

• Problems leaks,
• explosions

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Coal
Carbon (energy content) and sulfur
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Coal

• Bituminous most abundant (52), but
• high in sulfur

• Anthracite most ideal (high energy, low
• sulfur), but least abundant (2)

• Lignite (8) low energy, low pollution
• potential

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Coal

• Surface versus subsurface mines

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North American Energy Resources
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Burning Coal More Cleanly

• Fluidized-Bed Combustion

-calcium sulfate (limestone) used w/ Coal.
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Coal Gasification - methane
Raw coal
Recover sulfur
Air or oxygen
Raw gases
Steam
Clean methane gas
O2
2CO
2C Coal

Pulverizer
Recycle unreacted carbon (char)
CO

3H2
CH4

H2O
Methane (natural gas)
Slag removal
Pulverized coal
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Coal Liquefaction - liquid fuels

• Both gasification and liquefaction lose
• 30-40 of energy contained in coal

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Nuclear Energy

• Tremendous potential, plagued by
• safety and cost problems

• 3 ways to produce nuclear power
• 1) conventional nuclear fission reactor
• 2) breeder nuclear fission reactor
• 3) nuclear fusion reactor

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Nuclear Energy

• Use radioactive isotopes

• Isotopes - different forms of same
• element
• - atoms have differing masses
• - e.g. U-238, U-235

• Radioactive - unstable atoms emit
• radiation (rays and particles)

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Nuclear Energy

• Conventional fission reactors

• Uranium-235
• (U-238 common)

• Nucleus split by moving neutron

- Core, heat exchanger, generator
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Reactors in the United States
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Nuclear Energy

• Breeder fission reactors

• Uses plutonium-239 as fuel
• U-238 neutron Pu-239

• Pu-239 fissioned, but more produced
• from U-238
• - produces more Pu-239 than it uses

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Nuclear Energy

• Nuclear fusion reactors

• Combine atoms of hydrogen isotopes
• - deuterium, tritium

• Requires high temperature
• - 100 million C
• - experimental
• - uncontrolled fusion hydrogen bomb

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Problems with Nuclear Power

• Safety

• Disposal of radioactive wastes

• Use of fuel for weapons

• Reduced growth in demand for electricity

• High construction, operating costs

• Funding

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Safety Concerns

• Radiation concerns

• Susceptible tissues reproductive organs, bone
  marrow, digestive tract, spleen, lymph glands,
  fetuses

• Rem - unit of radiation exposure
• - 10 rems low level, few effects
• - 100 rems sterility, no short-term deaths
• - 1000 rems death in days

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Big Fears

• Core meltdown
• - Chernobyl 86

• Containment shell rupture

• Both have potential for releasing huge amounts of
  radiation

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Disposal of Radioactive Wastes
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Disposal of Radioactive Wastes

• No long-term storage facility
• - protected for 10,000 years
• - radiation declines to low levels

• Most wastes stored on-site

• Site under development
• - Yucca Mountain in Nevada

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Yucca Mountain
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Temporary Storage