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Mrs. Sealy

APES

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I. Mining Law of 1872

encouraged mineral exploration and

mining.

1.

First declare your belief that minerals on theland. Then spend $500 in improvements, pay$100 per year and the land is yours

2.Domestic and foreign companies take out

$2-$3 billion/ year 3.

Allows corporations and individuals to claimownership of U.S. public lands.

4.Leads to exploitation of land and mineralresources.

http://seattlepi.nwsource.com/specials/mining/26875_mine11.shtml

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" This arch aic, 132-year-old lawpermits mining companies to

gou ge bi l lions of dol lars wor th

of m inerals f rom pub l ic lands,

wi thou t pay ing one red cent to

the real ow ners, the Am erican

people.And , these same com panies

often leave the unsu spect ing

taxpayers w ith the bi l l for the

bi l l ions of dol lars required to

clean up the environmental

mess lef t behin d." -- Senator Dale Bumpers (D-

AR, retired)

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Nature and Formation of Mineral

Resources

A.onrenewable Resources

aconcentration of naturally occurring

material in or on the earths crust that can

be extracted and processed at an

affordable cost. Non-renewable resources

are mineral and energy resources such

as coal, oil, gold, and copper that take a

long period of time to produce.

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Nature and Formation of Mineral

Resources

1. Metallic Mineral Resourcesiron,copper, aluminum

2. Nonmetallic Mineral Resources

salt, gypsum, clay, sand, phosphates,water and soil.

3.Energy resource: coal, oil, natural gas

and uranium

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Nature and Formation of Mineral

Resources

B.

Identified Resourcesdeposits of anonrenewable mineral resource that have aknown location, quantity and quality based ondirect geological evidence and measurements

C.

Undiscovered Resourcespotentialsupplies of nonrenewable mineral resourcesthat are assumed to exist on the basis ofgeologic knowledge and theory (specific

locations, quantity and quality are not known) D.

Reservesidentified resources of mineralsthat can be extracted profitably at currentprices.

Other Resourcesresources that are not classified as reserves.

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Ore Formation

Hydrothermal Processes: most common way of mineralformation

A. Gaps in sea floor are formed by retreating tectonic plates

B. Water enters gaps and comes in contact with magma

C. Superheated water dissolves minerals from rock or magma

D. Metal bearing solutions cool to form hydrothermal oredeposits.

E.Black Smokersupwelling magma solidifies. Miniaturevolcanoes shoot hot, black, mineral rich water through vents ofsolidified magma on the seafloor. Support chemosynthetic

organisms.

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Ore Formation

Manganese Nodules (pacific ocean)ore nodules crystallized from hotsolutions arising from volcanic activity.

Contain manganese, iron copper andnickel.

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Methods For Finding

Mineral Deposits

A. Photos and Satellite Images

B. Airplanes fly with radiation equipment

and magnetometers

C. Gravimeter (density)

D. Drilling

E. Electric Resistance Measurement

F. Seismic Surveys G. Chemical analysis of water and plants

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Mineral Extraction

Surface Mining: overburden(soil and rock ontop of ore) is removed and becomes spoil.

1. open pit miningdigging holes

2. Dredgingscraping up underwater mineraldeposits

3. Area Strip Miningon a flat area anearthmover strips overburden

4. Contour Strip Miningscraping ore fromhilly areas

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Subsurface Mining:

1. dig a deep vertical shaft, blastunderground tunnels to get mineral deposit,remove ore or coal and transport tosurface

2. disturbs less land and produces lesswaste

3. less resource recovered, moredangerous and expensive

4. Dangers: collapse, explosions (naturalgas), and lung disease

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Environmental Impacts

of Mineral Resources

A.Scarring and disruption of land, B.Collapse or subsidence

C.Wind and water erosion of toxic lacedmine waste

D.Air pollutiontoxic chemicals

E.Exposure of animals to toxic waste

F.Acid mine drainage: seeping rainwater

carries sulfuric acid ( acid comes frombacteria breaking down iron sulfides) fromthe mine to local waterway

Google earth

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Steps Environmental Effects

exploration, extraction

MiningDisturbed land; mining accidents;health hazards; mine waste dumping;oil spills and blowouts; noise;ugliness; heat

Solid wastes; radioactive material;air, water, and soil pollution;

noise; safety and healthhazards; ugliness; heat

Processing

transportation, purification,manufacturing

Use

transportation or transmission

to individual user,eventual use, and discarding

Noise; uglinessthermal water pollution;

pollution of air, water, and soil;

solid and radioactive wastes;safety and health hazards; heat

Fig. 14.6, p. 326

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Percolation to groundwater

Leaching of toxic metals

and other compounds

from mine spoil

Acid drainage from

reaction of mineral

or ore with water

Spoil banks

Runoff of

sediment

Surface MineSubsurface

Mine Opening

Leaching

may carry

acids into

soil and

ground

water

supplies

Fig. 14.7, p. 326

S lti

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Surface

mining

Metal ore

Separation

of ore from

gangue

Scattered in environment

Recycling

Discarding

of product

Conversion

to product

Meltingmetal

Smelting

Fig. 14.8, p. 327

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A. Life Cycle of Metal

Resources (fig. 14-8)

Mining Ore A.Ore has two components: gangue(waste)

and desired metal

B.Separation of ore and gangue which

leaves tailings C.Smelting (air and water pollution and

hazardous waste whichcontaminates the soil around the smelter for

decades) D.Melting Metal

E.Conversion to product and discardingproduct

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Economic Impact on

Mineral Supplies

A.Mineral prices are low because ofsubsidies: depletion allowances and deductcost of finding more

B.Mineral scarcity does not raise the market

prices C.Mining Low Grade Ore: Some analysts

say all we need to do is mine more lowgrade ores to meet our need

1.We are able to mine low grade ore dueto improved technology

2.The problem is cost of mining and processing,availability of fresh water, environmental impact

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Present Depletion

time A

Depletion

time B

Depletion

time C

Time

Production

C

B

A

Recycle, reuse, reduce

consumption; increase

reserves by improved

mining technology,

higher prices, and

new discoveries

Recycle; increase reserves

by improved mining

technology, higher prices,

and new discoveries

Mine, use, throw away;

no new discoveries;

rising prices

Fig. 14.9, p. 329

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Fig. 14.10, p. 329

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A. Mining Oceans

1. Minerals are found in seawater, butoccur in too low of a concentration

2. Continental shelf can be mined

3. Deep Ocean are extremely expensiveto extract (not currently viable)

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Evaluating Energy Sources

What types of energy do we use? 1. 99% of our heat energy comes

directly from the sun (renewable fusion

of hydrogen atoms) 2. Indirect forms of solar energy(renewable)

wind

hydro biomass

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Mined coal

Pipeline

Pump

Oil well

Gas well

Oil storage

CoalOil and Natural Gas Geothermal Energy

Hot water

storageContour

strip mining

PipelineDrilling

tower

Magma

Hot rock

Natural gas

Oil

Impervious rock

Water Water

Oil drilling

platformon legs

Floating oil drilling

platform

Valves

Underground

coal mine

Water is heated

and brought up

as dry steam or

wet steam

Water

penetrates

down

through

the

rock

Area stripmining

Geothermal

power plant

Coal seam

Fig. 14.11, p. 332

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Primitive

Hunter

gatherer

Early

agricultural

Advanced

agricultural

Early

industrial

Modern industrial(other developed

nations)

Modern industrial

(United States)

Society Kilocalories per Person per Day

260,000

130,000

60,000

20,000

12,000

5,000

2,000 Fig. 14.12, p. 333

Nuclear power

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World

NaturalGas23%

Coal22%

Biomass12%

Oil

30%

Nuclear power6%

Hydropower, geothermal,Solar, wind

7%

Fig. 14.13a, p. 333

Nuclear power

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United States

Oil

40%

Coal22%

NaturalGas22%

Nuclear power7%

Hydropowergeothermal,solar, wind

5%

Biomass4%

Fig. 14.13b, p. 333

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20th Century Trends

1. Coal use decreases from 55% to 22% 2. Oil increased from 2% to 30%

3. Natural Gas increased from 0% to

25% 4. Nuclear increased from 0% to 6%

100

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Year

210020251950187518000

20

40

60

80

100

Contributiontototalener

gy

consum

ption(percent)

Wood

Coal

Oil

Nuclear

HydrogenSolar

Natural gas

Fig. 14.14, p. 334

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Evaluating Energy Sources

Evaluating Energy Resources; Take intoconsideration the following:

Availability

net energy yield Cost

environmental impact

Space Heating

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Space Heating

Passive solar

Natural gas

Oil

Active solar

Coal gasificationElectric resistance heating(coal-fired plant)

Electric resistance heating

(natural-gas-fired plant)

Electric resistance heating(nuclear plant) 0.3

0.4

0.4

1.5

1.9

4.5

4.9

5.8

Fig. 14.15a, p. 335

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High-Temperature Industrial Heat

Surface-mined coal

Underground-mined coal

Natural gasOil

Coal gasification

Direct solar (highlyconcentrated by mirrors,heliostats, or other devices)

0.9

1.54.74.9

25.8

28.2

Fig. 14.15b, p. 335

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Transportation

Natural gas

Gasoline (refined crude oil)

Biofuel (ethyl alcohol)

Coal liquefaction

Oil shale 1.2

1.4

1.9

4.1

4.9

Fig. 14.15c, p. 335

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Net Energy

Net Energytotal amount of energyavailable from a given source minus theamount of energy used to get the

energy to consumers (locate, remove,process and transport)

G. Net Energy Ratio- ratio of useful

energy produced to the useful energyused to produce it.

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Oil

A. Petroleum/Crude Oilthick liquidconsisting of hundreds of combustiblehydrocarbons and small concentrations of

nitrogen, sulfur, and oxygen impurities. B. Produced by the decomposition of

dead plankton that were buried under

ancient lakes and oceans. It is founddispersed in rocks.

http://www.schoolscience.co.uk/content/4/chemistry/petrole

um/knowl/4/2index.htm?origin.html

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Oil Life Cycle

1. Primary OilRecovery

a. drill well

b. pump out lightcrude oil

http://science.howstuffworks.com/oil-drilling3.htm

1:14

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Secondary Oil Recovery

a. pump waterunder pressure into awell to force heavycrude oil toward the

well b. pump oil and

water mixture to the

surface c. separate oil and

water

d. reuse water to get

more oil

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Tertiary Oil Recovery

a. inject detergent to dissolve theremaining heavy oil

b. pump mixture to the surface c. separate out the oil

d. reuse detergent

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Transport oil to the refinery (pipeline,truck, boat)

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Oil refining

heating and distilling based on boilingpoints of the various petrochemicalsfound in the crude oil. (fractional

distillation in a cracking tower)

Gases

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Diesel oil

Asphalt

Greaseand wax

Naphtha

Heating oil

Aviation fuel

Gasoline

FurnaceFig. 14.16, p. 337

Heatedcrude oil

C i t d t

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Conversion to product

a. Industrial organic chemicals b. Pesticides

c. Plastics

d. Synthetic fibers

e. Paints

f. Medicines

g. Fuel

L ti f W ld Oil

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. Location of World Oil

Supplies

1. 64% Middle East (67% OPEC11 countries) a. Saudi Arabia (26%) b. Iraq, Kuwait, Iran, (9-10% each)

2. Latin America (14%) (Venezuela and Mexico)

3. Africa (7%)

4. Former Soviet Union (6%)

5. Asia (4%) (China 3%)

6. United States (2.3%) we import 52% of the oil weuse

7. Europe (2%)

Arctic

Ocean

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MEXICO

UNITED STATES

CANADA

Pacific

Ocean

Atlantic

Ocean

GrandBanks

Gulf of

AlaskaValdez

ALASKABeaufort

Sea

Prudhoe Bay

Ocean

Coal

Gas

Oil

High potentialareas

Prince WilliamSound

Arctic National

Wildlife RefugeTrans Alaska

oil pipeline

Fig. 14.17, p. 338

70

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Year

1950 1960 1970 1980 1990 2000 20100

10

20

30

40

50

60

Oilpriceperbarrel($)

(1997 dollars)

Fig. 14.18, p. 339

40

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World

Year

1900 1925 1950 1975 2000 2025 2050 2075 21000

10

20

30

Annualproduction

(x109bar

relsperyear)

2,000 x 109barrels total

Fig. 14.19a, p. 339

4

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United States

Year1900 1920 1940 1960 2080 2000 2020 20400

1

2

3

Annualproduction

(x109barrelsperyear)

Provenreserves:

34 x 109barrels

200 x 109barrels total

1975

Undiscovered:32 x 109barrels

Fig. 14.19b, p. 339

Coal-fired 286%

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Nuclear power

Natural gas

Oil

Coal

Synthetic oil and

gas producedfrom coal

Coal-firedelectricity

17%

58%

86%

100%

150%

286%

Fig. 14.20, p. 339

Ad t Di d t

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Low land use

Easily transportedwithin andbetween countries

High net

energy yield

Low cost (withhuge subsidies)

Ample supply for4293 years

Advantages

Moderate waterpollution

Releases CO2when burned

Air pollutionwhen burned

Artificially lowprice encourageswaste anddiscourages

search foralternatives

Need to findsubstitute within

50 years

Disadvantages

Fig. 14.21, p. 340

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How long will the oil last

1. Identified Reserve will last 53 years atcurrent usage rates

2. Known and projected supplies are

likely to be 80% depleted within 42 to 93years depending on usage rate

US oil supplies are expected to be depletedwithin 15 to 48 years depending on theannual usage rate

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Heavy Oils

Oil Shalefine grained sedimentary rockcontaining solid organic combustible materialcalled kerogenShale Oilkerogen distilledfrom oil shale.

a. could meet U.S. crude oil demand for 40years at current usage rates (Colorado, Utah

and Wyoming public lands)

Tar Sandmixture of clay sand and water

containing bitumen (high sulfur heavy oil)

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Fig. 14.22, p. 340

Mined oil shale

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Above Ground

Conveyor

Conveyor

Spent shale

Pipeline

Retort

Aircompressors

Shale oilstorage

Impuritiesremoved

Hydrogenadded

Crude oil Refinery

Air

injectionShale layer

Underground

Shale heated to vaporized kerogen, which is condensed to provide shale oil

Sulfur and nitrogencompounds

Fig. 14.23, p. 341

Shale oil pumped to surface

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Hydrogenadded

Impuritiesremoved

Syntheticcrude oil

Refinery

Pipeline

Tar sand is mined. Tar sand is heateduntil bitumen floats

to the top.

Bitumen vaporIs cooled andcondensed.

Fig. 14.24, p. 341

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Advantages Disadvantages

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Advantages Disadvantages

Moderate existingsupplies

Large potentialsupplies

High costs

Low net energy

yield

Large amount ofwater needed toprocess

Severe landdisruption fromsurface mining

Water pollutionfrom miningresidues

Air pollutionwhen burned

CO2

emissionswhen burned

Fig. 14.25, p. 342

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XI. Natural Gas

Natural Gas is a mixture of 50-90% methane(CH4) by volume; contains smaller amounts ofethane, propane, butane and toxic hydrogensulfide.

B. Conventional natural gas- lies above mostreservoirs of crude oil

C. Unconventional deposits- include coal

beds, shale rock, deep deposits of tight sandsand deep zones that contain natural gasdissolved in hot hot water

C lOil d N t l G G th l E

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Mined coalPipeline

Pump

Oil well

Gas well

Oil storage

CoalOil and Natural Gas Geothermal Energy

Hot water

storageContour

strip mining

PipelineDrilling

tower

Magma

Hot rock

Natural gas

Oil

Impervious rock

Water Water

Oil drilling

platformon legs

Floating oil drilling

platform

Valves

Underground

coal mine

Water is heated

and brought up

as dry steam orwet steam

Water

penetrates

down

through

the

rock

Area stripmining

Geothermal

power plant

Coal seam

Fig. 14.11, p. 332

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XI. Natural Gas

Gas Hydrates- an ice-like material thatoccurs in underground deposits (globally)

Liquefied Petroleum Gas (LPG)- propaneand butane are liquefied and removed from

natural gas fields. Stored in pressurizedtanks.

Liquefied Natural Gas (LNG) - natural gas is

converted at a very low temperature (-184oC)

Where is the worlds

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natural gas?

Russia and Kazakhstan - 40%Iran - 15%Qatar - 5%

Saudi Arabia - 4%Algeria - 4%United States - 3%Nigeria - 3%

Venezuela - 3%

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Advantages:

1. Cheaper than Oil2. World reserves - >125 years

3. Easily transported over land (pipeline)

4. High net energy yield

5. Produces less air pollution than other fossil fuels6. Produces less CO2 than coal or oil

7. Extracting natural gas damages the environment muchless that either coal or uranium ore

8. Easier to process than oil

9. Can be used to transport vehicles

10. Can be used in highly efficient fuel cells

Advantages Disadvantages

A l li R l CO

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Good fuel for

fuel cells andgas turbines

Low land use

Easily transportedby pipeline

Moderate environ-mental impact

Lower CO2emissions thanother fossil fuels

Less air pollutionthan otherfossil fuels

Low cost (withhuge subsidies)

High net energyyield

Ample supplies(125 years)

Sometimesburned off andwasted at wellsbecause of lowprice

Shipped acrossocean as highlyexplosive LNG

Methane(a greenhouse

gas) can leakfrom pipelines

Releases CO2when burned

Fig. 14.26, p. 342

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Disadvantages:

1. When processed, H2S and SO2 arereleased into the atmosphere

2. Must be converted to LNG before it canbe shipped (expensive and dangerous)

3. Conversion to LNG reduces net energyyield by one-fourth

4. Can leak into the atmosphere; methane

is a greenhouse gas that is more potentthan CO2.

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XII. Coal

Coal is a solid, rocklikefossil fuel; formed inseveral stages as theburied remains ofancient swamp plantsthat died during theCarboniferous period(ended 286 million yearsago); subjected tointense pressure andheat over millions ofyears.

Coal is mostly carbon(40-98%); small amountof water, sulfur andother materials

Three types of coal

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Three types of coal

lignite (brown coal) bituminous coal (soft coal)

anthracite (hard coal)

Carbon content increases as coal ages;heat content increases with carboncontent

Increasing heat and carbon content

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Increasing moisture content

Increasing heat and carbon content

Peat(not a coal)

Lignite(brown coal)

Bituminous Coal(soft coal)

Anthracite(hard coal)

Heat

Pressure Pressure Pressure

Heat Heat

Partially decayed

plant matter in swamps

and bogs; low heat

content

Low heat content;

low sulfur content;

limited supplies in

most areas

Extensively used

as a fuel because

of its high heat content

and large supplies;

normally has a

high sulfur content

Highly desirable fuel

because of its high

heat content and

low sulfur content;

supplies are limited

in most areas

Fig. 14.27, p. 344

C l E t ti

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Coal Extraction

Subsurface Mining- labor intensive;worlds most dangerous occupation

(accidents and black lung disease

Surface Mining - three types 1. Area strip mining

2. contour strip mining

3. open-pit mining

CoalOil and Natural Gas Geothermal Energy

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Mined coalPipeline

Pump

Oil well

Gas well

Oil storage

CoalOil and Natural Gas Geothermal Energy

Hot water

storageContour

strip mining

PipelineDrilling

tower

Magma

Hot rock

Natural gas

Oil

Impervious rock

Water Water

Oil drilling

platform

on legs

Floating oil drilling

platform

Valves

Underground

coal mine

Water is heated

and brought up

as dry steam orwet steam

Water

penetrates

down

through

the

rock

Area stripmining

Geothermal

power plant

Coal seam

Fig. 14.11, p. 332

Wh d l

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Why we need coal

Coal provides 25% of worldscommercial energy (22% in US).

Used to make 75% of worlds steel

Generates 64% of worlds electricity

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Coal-Fired Electric Power

Plant

Coal is pulverized to a fine dust andburned at a high temperature in a hugeboiler. Purified water in the heat

exchanger is converted to high-pressuresteam that spins the shaft of the turbine.The shaft turns the rotor of thegenerator (a large electromagnet) to

produce electricity.

http://www.eas.asu.edu/~holbert/eee463/coal.html

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. Coal-Fired Electric Power

Plant

Air pollutants are removed usingelectrostatic precipitators (particulatematter) and scrubbers (gases). Ash is

disposed of in landfills. Sulfur dioxideemissions can be reduced by using low-sulfur coal.

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I Worlds Coal Supplies

US - 66% of worlds proven reservesIdentified reserves should last 220 yearsat current usage rates. Unidentified

reserves could last about 900 years

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. Pros and Cons of Solid

Coal

Advantages Worlds most abundant and dirtiest fossil

fuel, High net energy yield

Advantages Disadvantages

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Low cost (withhuge subsidies)

High net energyyield

Ample supplies(225900 years)

Releasesradioactiveparticles and

mercury into air

High CO2emissionswhen burned

Severe threat tohuman health

High land use(including mining)

Severe landdisturbance, airpollution, andwater pollution

Very highenvironmentalimpact

Fig. 14.28, p. 344

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Disadvantages:

harmful environmental effects

-mining is dangerous (accidents and -black lung disease)-harms the land and causes water pollution-Causes land subsidence-Surface mining causes severe land disturbance and soil erosion-Surface mined land can be restored - involves burying toxic materials,returning land to its original contour, and planting vegetation (Expensiveand not often done)

-Acids and toxic metals drain from piles of water materials-Coal is expensive to transport-Cannot be used in sold form in cars (must be converted to liquid orgaseous form)-Dirtiest fossil fuel to burn releases CO, CO2, SO2, NO, NO2, particulatematter (flyash), toxic metals and some radioactive elements.-Burning Coal releases thousands of times more radioactive particles intothe atmosphere per unit of energy than does a nuclear power plant-Produces more CO2 per unit of energy than other fossil fuels andaccelerates global warming.-A severe threat to human health (respiratory disease)

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Clean Coal Technology

. Fluidized-bed combustion- developedto burn coal more cleanly and efficiently.

Use of low sulfur coal - reduces SO2

emission Coal gasificationuses coal to produce

synthetic natural gas (SNG)

. Coal liquefaction- produce a liquid fuel- methanol or synthetic gasoline

Flue gases

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Calcium sulfate

and ash

Air

Air nozzles

Water

Fluidized bed

Steam

Coal Limestone

Fig. 14.29, p. 345

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Raw coal

Pulverizer

Air or

oxygen

Steam

Pulverized coal

Slag removal

Recycle unreacted

carbon (char)

Raw gases Clean

Methane

gas

Recover

sulfur

Methane(natural gas)

2C

Coal

+ O2 2CO

CO + 3H2 CH4 + H2O

Remove dust,

tar, water, sulfur

Fig. 14.30, p. 345

Advantages Disadvantages

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Advantages Disadvantages

Large potentialsupply

Vehicle fuel

Low to moderatenet energy yield

Higher cost thancoal

Highenvironmental

impact

Increased surfacemining of coal

High water use

Higher CO2emissions thancoal

Fig. 14.31, p. 346

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Clean Coal Technology

Synfuels- can be transported by pipelineinexpensively; burned to produceelectricity; burned to heat houses andwater; used to propel vehicles.

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XIII. Nuclear Energy

A. Three reasons why nuclear power plantswere developed in the late 1950s:

1. Atomic Energy Commission promised

electricity at a much lower cost than coal

2. US Govt paid ~1/4 the cost of building the

first reactors

3. Price Anderson Act protected nuclear

industry from liability in case of accidents

375

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Gigawattsofelectricity

1960 1970 1980 1990 2000 2010 2020

Year

0

75

150

225

300

Fig. 14.34a, p. 348

35

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Gigawattsofelectricity

Year

1960 1970 1980 1990 2000 20100

5

10

15

20

25

30

Fig. 14.34b, p. 348

Why is nuclear power on

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the decline?

B. Globally, nuclear energy produces only 17% ofworlds electricity (6% of commercial energy)

-huge construction overruns-high operating costs-frequent malfunctions

-false assurances-cover-ups by government and industry-inflated estimates of electricity use-poor management-Chernobyl

-Three Mile Island-public concerns about safety, cost and disposal ofradioactive wastes

C. How a Nuclear Reactor

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Works

Nuclear fission of Uranium-235 andPlutonium-239 releases energy that isconverted into high-temperature heat.This rate of conversion is controlled. Theheat generated can produce high-pressure steam that spins turbines thatgenerate electricity.

Small amounts of Radioactive gasesUranium fuel input

(reactor core)

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Periodic removal

and storage of

radioactive wastesand spent fuel assemblies

Periodic removal

and storage of

radioactive liquid wastes

Pump

Steam

Water

Black

Turbine Generator

Waste heat Electrical power

Hot water output

Condenser

Cool water input

Pump

Pump Waste

heat

Useful energy

25 to 30%

Waste

heatWater source

(river, lake, ocean)

Heat

exchanger

Containment shell

Emergency core

Cooling system

Control

rods

Moderator

Pressurevessel

Shielding

Coolant

passage

Fig. 14.32, p. 346

CoolantCoolant

Hot coolantHot coolant

Fuel assemblies Reactor Spent fuel assemblies

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Front end Back end

Uranium mines and mills

Ore and ore concentrate (U3O8)

Geologic disposal

of moderate-

and high-level

radioactive wastes

High-level

radioactive

waste or

spent fuel

assemblies

Uranium tailings

(low level but

long half-life)

Conversion of U3O8

to UF6

Processed

uranium ore

Uranium-235as UF6

Enrichment

UF6

Enriched

UF6

Fuel fabrication

Spent fuel

reprocessing

Plutonium-239

as PuO2

(conversion of enriched UF6to UO2

and fabrication of fuel assemblies)

Fuel assemblies Reactor p

Interim storage

Under water

Open fuel cycle today

Prospective closed

end fuel cycle

Decommissioning

of reactor

Decommissioning

of reactor

Spent fuel

assemblies

Spent fuel

assemblies

Fig. 14.33, p. 347

D. Light-water reactors

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LWR)

1. Core containing 35,000-40,000 fuel rodscontaining pellets of uranium oxide fuel. Pelletis 97% uranium-238 (nonfissionable isotope)and 3% uranium-235 (fissionable).

2. Control rods- move in and out of the

reactor to regulate the rate of fission 3. Moderator- slows down the neutrons so the

chain reaction can be kept going [ liquid waterin pressurized water reactors; solid graphite or

heavy water (D2O) ]. 4. Coolant- water to remove heat from thereactor core and produce steam

Decommissioning Power

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Plants

1/3 of fuel rod assemblies must be replacedevery 3-4 years. They are placed in concretelined pools of water (radiation shield andcoolant).

A. Nuclear wastes must be stored for 10,000

years B. After 15-40 years of operation, the plant

must be decommissioned by 1. dismantling it

2. putting up a physical barrier, or 3. enclosing the entire plant in a tomb (to last

several thousand years)

Large fuel High cost (even

Advantages Disadvantages

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Low risk ofaccidents

because ofmultiplesafety systems(except in 35poorly designedand run reactorsin former SovietUnion and

Eastern Europe)

Moderate land use

Moderate landdisruption andwater pollution(withoutaccidents)

Emits 1/6 asmuch CO2 as coal

Lowenvironmentalimpact (without

accidents)

gsupply

Spreadsknowledge andtechnology forbuilding nuclearweapons

No acceptablesolution forlong-term storageof radioactivewastes and

decommissioningworn-out plants

Catastrophicaccidents can

happen(Chernobyl)

Highenvironmentalimpact (with majoraccidents)

Low netenergy yield

g (with largesubsidies)

Fig. 14.35, p. 349

Coal

Ample supply

Nuclear

Ample supply

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p pp y

High net energyyield

Very high airpollution

High CO2emissions

65,000 to 200,000deaths per yearin U.S.

High landdisruption fromsurface mining

High land use

Low cost (withhuge subsidies)

p pp yof uranium

Low net energyyield

Low air pollution(mostly from fuelreprocessing)

Low CO2emissions

(mostly from fuelreprocessing)

About 6,000deaths peryear in U.S.

Much lower landdisruption fromsurface mining

Moderate landuse

High cost (with

huge subsidies)

Fig. 14.36, p. 349

F. Advantages of Nuclear

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Power:

1. Dont emit air pollutants 2. Water pollution and land disruption are

low

G. Nuclear Power Plant

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Safety

1. Very low risk of exposure to radioactivity

2. Three Mile Island - March 29, 1979; No. 2 reactorlost coolant water due to a series of mechanical failuresand human error. Core was partially uncovered

3. Nuclear Regulatory Commission estimates there is a

15-45% chance of a complete core meltdown at a USreactor during the next 20 years.

4. US National Academy of Sciences estimates that USnuclear power plants cause 6000 premature deaths and3700 serious genetic defects each year.

http://www.angelfire.com/extreme4/kiddofspeed/chapter1.html

Crane for

moving fuel rods

Automatic safety devicesthat shut down the reactor

when water and steam levels

fall below normal and turbine

Almost all control rodswere removed from the

core during experiment.

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Steam

generator

Water

pumps

TurbinesTurbines

ReactorReactor

Cooling

pond

Cooling

pond

Reactor power output was lowered too

much, making it too difficult to control.

Additional water pump to cool reactor

was turned on. But with low power output

and extra drain on system, water didnt

actually reach reactor.

fall below normal and turbine

stops were shut off because

engineers didnt want system

to spoil experiment.

Radiation shieldsRadiation shields

Emergency cooling

system was turned

off to conduct an

experiment.

Fig. 14.37, p. 350Chernobyl

H. Low-Level Radioactive

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Waste

1. Low-level waste gives off small amounts of ionizing

radiation; must be stored for 100-500 years beforedecaying to levels that dont pose an unacceptable riskto public health and safety

2. 1940-1970: low-level waste was put into drums anddumped into the oceans. This is still done by UK and

Pakistan 3. Since 1970, waste is buried in commercial,

government-run landfills. 4. Above-ground storage is proposed by a number of

environmentalists.

5. 1990: the NRC proposed redefining low-levelradioactive waste as essentially nonradioactive. Thatpolicy was never implemented (as of early 1999).

I. High-Level Radioactive

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Waste

1. Emit large amounts of ionizingradiation for a short time and smallamounts for a long time. Must be storedfor about 240,000

2. Spent fuel rods; wastes from plantsthat produce plutonium and tritium fornuclear weapons.

J. Possible Methods of Disposal

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and their Drawbacks

1. Bury it deep in the ground 2. Shoot it into space or into the sun 3. Bury it under the Antarctic ice sheet or the Greenland

ice cap 4. Dump it into descending subduction zones in the

deep ocean 5. Bury it in thick deposits of muck on the deep ocean

floor 6. Change it into harmless (or less harmful) isotopes 7. Currently high-level waste is stored in the DOE $2

billion Waste Isolation Pilot Plant (WIPP) nearCarlsbad, NM. (supposed to be put into operation in1999)

Up to 60deep trenches

As many as 20flatbed trucks

Barrels are stackedand surrounded

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Clay bottom

deep trenchesdug into clay.

flatbed trucksdeliver wastecontainers daily.

and surroundedwith sand. Coveringis mounded to aidrain runoff.

Fig. 14.38b, p. 351

What covers waste

Topsoil

Grass

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Clay

Gravel

Sand

Compacted clay

Soil

TopsoilGravel

Fig. 14.38c, p. 351

Waste container 2 meters wide25 meters high

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Steel wall

Steel wall

Severalsteel drumsholding waste

Lead shielding

Fig. 14.38a, p. 351

Storage Containers

F l d

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Fuel rod

Primary canister

Overpack containersealed

Fig. 14.39c, p. 352

Underground

B i d d d

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Buried and capped

Fig. 14.39d, p. 352

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Personnel elevator

Air shaft

Nuclear waste shaft

2,500 ft.(760 m)deep

Fig. 14.39b, p. 352

K. Worn-Out Nuclear Plants

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1. Walls of the reactors pressure vesselbecome brittle and thus are more likely tocrack.

2. Corrosion of pipes and valves

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Connection between Nuclear

Reactors and the Spread of Nuclear

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Weapons

1. Components, materials and informationto build and operate reactors can be usedto produce fissionable isotopes for use innuclear weapons.

Los Alamos Muon Detector CouldThwart Nuclear Smugglers

M. Can We Afford Nuclear

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Power?

1. Main reason utilities, the governmentand investors are shying away fromnuclear power is the extremely high costof making it a safe technology.

2. All methods of producing electricityhave average costs well below the costsof nuclear power plants.

N. Breeder Reactors

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1. Convert nonfissionable uranium-238 intofissionable plutonium-239

2. Safety: liquid sodium coolant could cause arunaway fission chain reaction and a nuclear

explosion powerful enough to blast open thecontainment building.

3. Breeders produce plutonium fuel too slowly;it would take 1-200 years to produce enoughplutonium to fuel a significant number of otherbreeder reactors.

O. Nuclear Fusion

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1. D-T nuclear fusion reaction; Deuteriumand Tritium fuse at about 100 milliondegrees

2. Uses more energy than it produces