Geologic Resources: Nonrenewable Mineral and Energy Resources

Geologic Resources: Nonrenewable Mineral and Energy Resources

Chapter 15

G. Tyler Miller’sLiving in the Environment

13th Edition

Chapter 15

G. Tyler Miller’sLiving in the Environment

13th Edition

Key ConceptsKey Concepts

• Types of mineral resourcesTypes of mineral resources• Formation and location of mineral Formation and location of mineral

resourcesresources• Extraction and processing of Extraction and processing of

mineral resourcesmineral resources• Increasing supplies of mineral Increasing supplies of mineral

resourcesresources• Major types, acquisition, Major types, acquisition,

advantages, and disadvantages of advantages, and disadvantages of fuel resourcesfuel resources

Nature and Formation of Mineral ResourcesNature and Formation of Mineral Resources

• Mineral resourcesMineral resources– MetallicMetallic

• Iron, copper, Iron, copper, aluminumaluminum

• OreOre - rock containing - rock containing one or more metallic one or more metallic mineralsminerals

– Non-metallicNon-metallic• Salt, clay, sand, Salt, clay, sand,

phosphates, soilphosphates, soil

– Energy ResourcesEnergy Resources• Coal, oil, gas, Coal, oil, gas,

uraniumuranium

Non-renewableNon-renewable

Nature and Formation of Mineral ResourcesNature and Formation of Mineral Resources

• MagmaMagma– Igneous rockIgneous rock

• Hydrothermal processesHydrothermal processes– Hydrothermal ore Hydrothermal ore

depositsdeposits– Black smokersBlack smokers

• Manganese nodulesManganese nodules• Weathering and Weathering and

sedimentary sortingsedimentary sorting– Residual depositsResidual deposits– Placer depositsPlacer deposits– Evaporite mineral Evaporite mineral

depositsdeposits

Magma

Black smoker

Sulfidedeposit

White crab

White clam Tube worms

Whitesmoker

Finding Nonrenewable Mineral ResourcesFinding Nonrenewable Mineral Resources

• Satellite imagerySatellite imagery• Aerial sensors (magnetometers)Aerial sensors (magnetometers)• Gravity differences (gravimeter)Gravity differences (gravimeter)• Core samplingCore sampling• Seismic surveysSeismic surveys• Chemical analysis of water and Chemical analysis of water and

plantsplants

Removing Nonrenewable Mineral ResourcesRemoving Nonrenewable Mineral Resources

• OverburdenOverburden– Layer of soil and Layer of soil and

rock overlaying rock overlaying mineral depositsmineral deposits

• SpoilsSpoils– Unwanted rock and Unwanted rock and

other materials in other materials in with orewith ore

• Open pitOpen pit• Strip miningStrip mining• Mountain removalMountain removal• DredgingDredging

• Surface Mining Control Surface Mining Control and Reclamation Act of and Reclamation Act of 19771977– Restore surface land like Restore surface land like

it was prior to mining.it was prior to mining.

– Levied tax on mining Levied tax on mining companies to restore land companies to restore land disturbed before the law disturbed before the law was passed.was passed.

Surface miningSurface mining

Open Pit Mine

Area Strip Mining

Contour Strip Mining

Mountain Top Removal

Removing Nonrenewable Mineral ResourcesRemoving Nonrenewable Mineral Resources

– Room and Room and pillarpillar

– LongwallLongwall• Disturbs less Disturbs less

land arealand area• Produces less Produces less

wastewaste• More More

dangerousdangerous and and expensiveexpensive

Subsurface miningSubsurface mining

Environmental Effects of Mining, Processing, and Using Mineral Resources

Environmental Effects of Mining, Processing, and Using Mineral Resources

Environmental Effects of Extracting (Mining) and Processing Mineral Resources

Environmental Effects of Extracting (Mining) and Processing Mineral Resources

• OreOre– Ore Ore

mineralmineral• Desired Desired

metalmetal

– GangueGangue• Waste Waste

materialmaterial

• TailingsTailings– Separated Separated

wastewaste

• SmeltingSmelting

Fig. 15-7 p. 344

Environmental Effects of Using Mineral ResourcesEnvironmental Effects of Using Mineral Resources

a)a) Disruption of land surfaceDisruption of land surface 500,000 mines500,000 mines

b)b) SubsidenceSubsidence

c)c) Erosion of solid mining wasteErosion of solid mining waste

d)d) Acid mine drainageAcid mine drainage HH22SOSO44

e)e) Air pollutionAir pollution Mining produces more toxic emissions Mining produces more toxic emissions

than any other industrythan any other industry

f)f) Storage and leakage of liquid Storage and leakage of liquid mining wastemining waste

Supplies of Mineral ResourcesSupplies of Mineral Resources

• Economic Economic depletiondepletion– Costs more to find, Costs more to find,

extract, transport, extract, transport, and process the and process the remaining deposit remaining deposit than it is worth than it is worth (10%)(10%)

– OptionsOptions• Recycle or reuse Recycle or reuse • Waste lessWaste less• Use lessUse less• Find a substituteFind a substitute• Do withoutDo without Fig. 15-9 p. 346Fig. 15-9 p. 346

Evaluating Energy ResourcesEvaluating Energy Resources

Renewable energy Renewable energy

Non-renewable energy Non-renewable energy

Future availability Future availability

Net energy yield Net energy yield

Cost Cost

Environmental effects Environmental effects Fig. 15-12 p. 351Fig. 15-12 p. 351

Important Nonrenewable Energy SourcesImportant Nonrenewable Energy Sources

Fig. 15-10 p. 350Fig. 15-10 p. 350

OilOil

• Crude OilCrude Oil– oil as it comes out of the groundoil as it comes out of the ground– thick liquid consisting of thick liquid consisting of

combustible hydrocarbonscombustible hydrocarbons– small amounts of sulfur, oxygen, small amounts of sulfur, oxygen,

and nitrogen impuritiesand nitrogen impurities– only 35% of the oil out of an oil only 35% of the oil out of an oil

depositdeposit– ““heavy crude oil”heavy crude oil”

Oil RefineryOil RefineryOil RefineryOil Refinery

• Separation based Separation based on on boiling pointsboiling points

• PetrochemicalsPetrochemicals– Raw materials used Raw materials used

in manufacturing in manufacturing such as organic such as organic chemicals, chemicals, pesticides, plastics, pesticides, plastics, synthetic fibers, synthetic fibers, paints, medicines…..paints, medicines…..

Fig. 15-18 p. 355Fig. 15-18 p. 355

North American Energy ResourcesNorth American Energy Resources

Fig. 15-20p. 356

World’s Oil SuppliesWorld’s Oil SuppliesWorld’s Oil SuppliesWorld’s Oil Supplies

• Organization of Petroleum Organization of Petroleum Exporting Countries (OPEC)Exporting Countries (OPEC)– 67% of the world’s oil reserves67% of the world’s oil reserves– Saudi Arabia : 26%Saudi Arabia : 26%– Kuwait, Iran, United Arab Emirates : 9-Kuwait, Iran, United Arab Emirates : 9-

10%10%– Latin America : 9%Latin America : 9%– Africa : 7%Africa : 7%– Former Soviet Union : 6%Former Soviet Union : 6%– Asia : 4%Asia : 4%– US : 3%US : 3%

Oil

(mill

ion

bar

rels

pe r

da y

)60

50

30

20

10

1970 1980 1990 2000 2010

Year

40

2020

History Projections

0

History Projections

U.S. supply, consumption, and U.S. supply, consumption, and importsimports

Consumption

Domestic supply

Net Imports

Oil Shale and Tar SandsOil Shale and Tar Sands

Oil shaleKeragen Keragen

Oil shaleKeragen Keragen

Tar sand BitumenBitumen

Tar sand BitumenBitumen

Fig. 15-28 p. 361Fig. 15-28 p. 361

Natural GasNatural Gas

• 50-90% Methane50-90% Methane• Conventional Conventional

natural gasnatural gas– Lies above crude Lies above crude

oil reservoirsoil reservoirs• Unconventional Unconventional

natural gasnatural gas– Found by itselfFound by itself– Methyl hydrateMethyl hydrate

• 200 year supply200 year supply

Fig. 15-29 p. 362Fig. 15-29 p. 362

Important Nonrenewable Energy Sources

Important Nonrenewable Energy Sources

Fig. 15-10 p. 350Fig. 15-10 p. 350

CoalCoal

• Stages of coal formationStages of coal formation

Fig. 15-30 p. 363Fig. 15-30 p. 363

CoalCoal

CoalCoal

• Stages of coal formationStages of coal formation• Primarily strip-mined.Primarily strip-mined.• Used most for generating electricityUsed most for generating electricity

– 21% of the world’s energy21% of the world’s energy

• Enough coal for about Enough coal for about 1000 years1000 years– Coal is the world’s most abundant fossil Coal is the world’s most abundant fossil

fuelfuel

• Highest environmental impact!Highest environmental impact!• Coal gasification and liquefaction may Coal gasification and liquefaction may

reduce impact.reduce impact.

Burning Coal More CleanlyBurning Coal More Cleanly

Fluidized-Bed Combustion

Fluidized-Bed Combustion

Fig. 15-32 p. 364Fig. 15-32 p. 364

NUCLEAR POWERNUCLEAR POWER

• President Dwight Eisenhower, 1953, “Atoms for Peace”speech.– Nuclear-powered electrical generators

would provide power “too cheap to meter.”• Between 1970 and 1974, American utilities

ordered 140 new reactors for power plants.

Nuclear PowerNuclear Power

• After 1975, only 13 orders were placed for new nuclear reactors, and all of those were subsequently cancelled.– In all, 100 of 140 reactors on order in 1975

were cancelled.• Construction costs, declining demand for

electrical power, safety fears• Electricity from nuclear power plants was

about half the price of coal in 1970, but twice as much in 1990.

Nuclear Power Plant HistoryNuclear Power Plant History

How Do Nuclear Reactors WorkHow Do Nuclear Reactors Work

• Most commonly used fuel is U235, a naturally occurring radioactive isotope of uranium.

• Occurs naturally at 0.7% of uranium, but must be enriched to about of 3%.

• Formed in cylindrical pellets (1.5 cm long) and stacked in hollow metal rods (4 m long).– About 100 rods and bundled together to make a

fuel assembly.– Thousands of fuel assemblies bundled in reactor

core.

How Do Nuclear Reactors WorkHow Do Nuclear Reactors Work

• When struck by neutrons, radioactive uranium atoms undergo nuclear fission (splitting) releasing energy and more neutrons.– Triggers nuclear chain reaction.

Nuclear FissionNuclear Fission

How Do Nuclear Reactors WorkHow Do Nuclear Reactors Work

• Reaction is moderated in a power plant by neutron-absorbing solution (Moderator).– In addition, Control Rods composed of

neutron-absorbing material are inserted into spaces between fuel assemblies to control reaction rate.• Cadmium or boron

– Water or other coolant is circulated between the fuel rods to remove excess heat.

Kinds of ReactorsKinds of Reactors

• Seventy percent of nuclear power plants are pressurized water reactors (PWR).– Water circulated through core to absorb

heat from fuel rods.– Pumped to steam generator where it

heats a secondary loop.– Steam from secondary loop drives high-

speed turbine producing electricity.

Kinds of ReactorsKinds of Reactors

• Both reactor vessel and steam generator are housed in a special containment building preventing radiation from escaping, and providing extra security in case of accidents.– Under normal operating conditions, a

PWR releases very little radioactivity.

PWRPWR

Periodic removaland storage of

radioactive wastesand spent fuel assemblies

Periodic removaland storage of

radioactive liquid wastes

Pump

Steam

Small amounts of radioactive gases

Water

Black

Turbine Generator

Waste heat Electrical power

Hot water output

Condenser

Cool water input

Pump

Pump Wasteheat

Useful energy25 to 30%

WasteheatWater source

(river, lake, ocean)

Heatexchanger

Containment shell

Uranium fuel input(reactor core)

Emergency corecooling system

Controlrods

Moderator

Pressurevessel

Shielding

Coolantpassage

CoolantCoolant

Hot coolantHot coolant

Kinds of ReactorsKinds of Reactors

• Simpler, but more dangerous design is a boiling water reactor (BWR).– Water from core boils to make steam, directly

driving turbine generators.– Highly radioactive water and steam leave

containment structure.

• Canadian deuterium reactors - Operate with natural, un-concentrated uranium.

• Graphite moderator reactors - Operate with a solid moderator instead of a liquid.

Alternative Reactor DesignsAlternative Reactor Designs

• High-Temperature, Gas-Cooled Reactors– Uranium encased in tiny ceramic-coated

pellets.

• Process-Inherent Ultimate Safety Reactors– Reactor core submerged in large pool of

boron-containing water within a massive pressure vessel.

Breeder ReactorsBreeder Reactors

• Breeder reactors create fissionable plutonium and thorium isotopes from stable forms of uranium.– Uses plutonium reclaimed from spent

fuel from conventional fission reactors as starting material.

Breeder ReactorsBreeder Reactors

Breeder Reactor DrawbacksBreeder Reactor Drawbacks

• Reactor core must be at very high density, thus liquid sodium used as a coolant.– Corrosive and difficult to handle.

• Core will self-destruct within a few seconds if primary coolant is lost.

• Produces weapons-grade plutonium.

RADIOACTIVE WASTE MANAGEMENTRADIOACTIVE WASTE MANAGEMENT

• Until 1970, the US, Britain, France, and Japan disposed of radioactive waste in the ocean.

• Production of 1,000 tons of uranium fuel typically generates 100,000 tons of tailings and 3.5 million liters of liquid waste.– Now approximately 200 million tons of

radioactive waste in piles around mines and processing plants in the US.

Radioactive Waste ManagementRadioactive Waste Management

• About 100,000 tons of low-level waste (clothing) and about 15,000 tons of high-level (spent-fuel) waste in the US.– For past 20 years, spent fuel assemblies

have been stored in deep water-filled pools at the power plants. (Designed to be “temporary”.)• Many internal pools are now filled and a

number plants are storing nuclear waste in metal dry casks outside.

Radioactive Waste ManagementRadioactive Waste Management

• US Department of Energy announced plans to build a high-level waste repository near Yucca Mountain Nevada in 1987.– Facility may cost

between $10 and 35 billion, and will not open until at least 2015.

Decommissioning Old Nuclear PlantsDecommissioning Old Nuclear Plants

• Most plants are designed for a 30 year operating life.– Only a few plants have thus far been

decommissioned.– General estimates are costs will be 2-10

times more than original construction costs.

CHANGING FORTUNESCHANGING FORTUNES

• Public opinion has fluctuated over the years.– When Chernobyl exploded in 1985, less

than one-third of Americans favored nuclear power.• Now, half of all Americans support nuclear-

energy.

• Currently, 103 nuclear reactors produce about 20% of all electricity consumed in the US.

Changing FortunesChanging Fortunes

• With natural gas prices soaring, and electrical shortages looming, many sectors are once again promoting nuclear reactors.– Over the past 50 years, the US

government has provided $150 billion in nuclear subsidies, but less than $5 billion to renewable energy research.

NUCLEAR FUSIONNUCLEAR FUSION• Nuclear Fusion - Energy released when two

smaller atomic nuclei fuse into one large nucleus. (Sun)

– Duterium and tritium, two heavy isotopes of H

– Temperatures must be raised to 100,000,000o C and pressure must reach several billion atmospheres.

– Advantages:• Production of few radioactive wastes• Elimination of products that could be made into bombs• Fuel supply that is larger and less hazardous than

uranium.

NUCLEAR FUSIONNUCLEAR FUSION

Despite 50 years and $25 billion, fusion reactors have never produced more energy than they consume!

US Energy PolicyUS Energy Policy

• Oil, coal, and natural gas remain the United States’ primary energy resources.

• Support the use of nuclear power as an environmentally friendly way to increase energy supplies.

Nuclear EnergyNuclear Energy Fission

reactors Fission

reactors

Uranium-235 Uranium-235

Potentially dangerous

Potentially dangerous

Radioactive wastes

Radioactive wastes

Refer to Introductory Essay p. 338Refer to Introductory Essay p. 338

Fig. 15-35 p. 366Fig. 15-35 p. 366

The Nuclear Fuel CycleThe Nuclear Fuel Cycle

Fig. 15-36p. 367

Dealing with Nuclear WasteDealing with Nuclear Waste

• Low-level wasteLow-level waste• High-level wasteHigh-level waste• Underground Underground

burialburial• Disposal in spaceDisposal in space• Burial in ice sheetsBurial in ice sheets• Dumping into Dumping into

subduction zonessubduction zones• Burial in ocean mudBurial in ocean mud• Conversion into Conversion into

harmless materialsharmless materials

Fig. 15-40p. 370

Nuclear AlternativesNuclear Alternatives

Breeder nuclear fission reactors

Breeder nuclear fission reactors

Nuclear fusion

Nuclear fusion New reactor designs

New reactor designsStorage Containers

Fuel rod

Primary canister

Overpackcontainersealed

Underground

Buried and capped

Ground Level

Unloaded from train

Lowered down shaft

Personnal elevatorAir shaft

Nuclear waste shaft

Fig. 15-42p. 376

Some Energy UnitsSome Energy Units1 joule (J) = force exerted by a current of

1 amp through a resistance of 1 ohm

1 watt (W) = 1 joule per second

1 kilowatt-hour = 1 thousand (103) watts exerted for 1 hour

1 megawatt (MW)

= 1 million (106) watts

1 British Thermal Unit (BTU)

= energy to heat 1 lb. of water 1 °F

1 standard barrel (bbl) of oil

= 42 gal (160 l) or 5.8 million BTUs

1 metric ton of coal

= 27.8 million BTU or 4.8 bbl oil