Chapter 15Chapter 15

Geologic Resources: Geologic Resources: Nonrenewable Mineral and Nonrenewable Mineral and

Energy ResourcesEnergy Resources

Key QuestionKey Question What are nonrenewable mineral resources What are nonrenewable mineral resources

and how are they formed?and how are they formed? How do we find and extract nonrenewable How do we find and extract nonrenewable

mineral and energy resources from the mineral and energy resources from the earth’s crust?earth’s crust?

How fast are mineral supplies being used How fast are mineral supplies being used up?up?

How should we evaluate energy How should we evaluate energy alternatives?alternatives?

What are advantages and disadvantages What are advantages and disadvantages of natural gas?of natural gas?

What are Mineral Resources?What are Mineral Resources?

Concentration of naturally occurring Concentration of naturally occurring material in or on the earth’s crust material in or on the earth’s crust that can be extracted and processed that can be extracted and processed into useful materialsinto useful materials

Classified as Classified as nonrenewable resourcesnonrenewable resources because they take so long to producebecause they take so long to produce

We know how to find and extract We know how to find and extract 100+ nonrenewable minerals from 100+ nonrenewable minerals from the earth’s crustthe earth’s crust

We can extract…We can extract…

Metallic mineral resourcesMetallic mineral resources (iron, (iron, copper, aluminum)copper, aluminum)

Nonmetallic mineral resourcesNonmetallic mineral resources (salt, (salt, clay, sand, phosphates, soil)clay, sand, phosphates, soil)

Energy resourcesEnergy resources (coal, oil, natural (coal, oil, natural gas, uranium)gas, uranium)

OreOre

Rock containing enough of 1+ Rock containing enough of 1+ metallic minerals to be mined for metallic minerals to be mined for profitprofit

We convert 40 metals extracted from We convert 40 metals extracted from ores into everyday items that are ores into everyday items that are either 1) used and thrown away OR either 1) used and thrown away OR 2) reused or recycled2) reused or recycled

Categories of nonrenewable Categories of nonrenewable mineral resourcesmineral resources

US Geological Survey divides nonrenewable US Geological Survey divides nonrenewable mineral resource into categories:mineral resource into categories:

1.1. Identified resourcesIdentified resources: deposits of nonrenewable : deposits of nonrenewable mineral resource with a known location and mineral resource with a known location and quantityquantity

2.2. Undiscovered resourcesUndiscovered resources: potential supplies : potential supplies assumed to exist in theoryassumed to exist in theory

3.3. ReservesReserves: identified resources from which : identified resources from which resource can be extracted for profitresource can be extracted for profit

4.4. Other resourcesOther resources: identified and discovered but : identified and discovered but not classified as reserves not classified as reserves

How do ores form from magma?How do ores form from magma?

Ores form as a result of internal and Ores form as a result of internal and external geologic processesexternal geologic processes

Plate tectonics shape the earth’s Plate tectonics shape the earth’s crust and determine where the crust and determine where the richest mineral deposits are foundrichest mineral deposits are found

As magma cools, it crystallizes into mineral-containing igneous rocks

Ore deposits form through hydrothermal processes

Upwelling magma solidifies into black smokers

Shoots out mineral-rich hot water on the seafloor

Minerals accumulate as hot and cold water contact

Form ore deposits rich in copper, lead, zinc, silver, and gold

Finding nonrenewable resourcesFinding nonrenewable resources

Aerial photos and satellite imagesAerial photos and satellite images Planes that detect deposits of radioactive Planes that detect deposits of radioactive

metalsmetals Gravimeter to measure differences in Gravimeter to measure differences in

density (ore differs from surrounding rock)density (ore differs from surrounding rock) Drilling deep well and extracting core Drilling deep well and extracting core

samplessamples Seismic surveys by explosions and Seismic surveys by explosions and

analyzing shock wavesanalyzing shock waves Chemical analysis of water and plants Chemical analysis of water and plants

(absorb minerals)(absorb minerals)

Mining techniques (once resources Mining techniques (once resources have been found)have been found)

Surface miningSurface mining: equipment strips outer layer of : equipment strips outer layer of soil and rock; in US, used to extract 90% nonfuel soil and rock; in US, used to extract 90% nonfuel resources and 60% coalresources and 60% coal

Open-pit miningOpen-pit mining: machines dig holes and remove : machines dig holes and remove oresores

DredgingDredging: chains scrape underwater mineral : chains scrape underwater mineral depositsdeposits

Area strip miningArea strip mining: parallel strips made in flat land; : parallel strips made in flat land; power shovels usedpower shovels used

Contour strip miningContour strip mining: terraces cut into side of hill; : terraces cut into side of hill; power shovels usedpower shovels used

Mountaintop removalMountaintop removal: explosives used to remove : explosives used to remove top of mountain and expose coal underneathtop of mountain and expose coal underneath

Open Pit Mine

Dredging

Area Strip Mining

Contour Strip Mining

Surface Mining Control and Surface Mining Control and Reclamation Act of 1977Reclamation Act of 1977

Requires mining companies to Requires mining companies to restore surface-mined land so that it restore surface-mined land so that it is usable againis usable again

Although surface-mined land can be Although surface-mined land can be restored, it is expensive and not restored, it is expensive and not done in many countriesdone in many countries

Subsurface miningSubsurface mining

Used to remove coal and other metal Used to remove coal and other metal ores that are too deep to be ores that are too deep to be extracted by surface miningextracted by surface mining

Blast tunnels to get to deposit, use Blast tunnels to get to deposit, use machinery to transport ore to the machinery to transport ore to the surfacesurface

Disturbs 1/10 as much land as Disturbs 1/10 as much land as surface mining, produces less wastesurface mining, produces less waste

More dangerous and expensive More dangerous and expensive

Environmental Effects of Extracting Environmental Effects of Extracting Mineral ResourcesMineral Resources

Fig. 15-6 p. 343

Percolation to groundwaterLeaching of toxic metalsand other compoundsfrom mine spoil

Acid drainage fromreaction of mineralor ore with water

Spoil banks

Runoff ofsediment

Surface MineSubsurfaceMine Opening

Leaching may carryacids into soil andgroundwater supplies

Acid mine drainage-pollution and degradationby acid runoff and toxic chemicals from mining-can kill fish and other aquatic life

Surface mining

Metal ore

Separationof ore frommachine

Scattered in environment

Recycling

Discarding of product

Conversion to product

Melting metal

Smelting

Processes involved in extractionProcesses involved in extraction

SmeltingSmelting: used to separate metal : used to separate metal from other elements in the orefrom other elements in the ore

Enormous amount of pollution which Enormous amount of pollution which damages surrounding vegetation and damages surrounding vegetation and soilsoil

Smelters also produce liquid and Smelters also produce liquid and hazardous waste that must be hazardous waste that must be disposed of safely disposed of safely

Are there environmental limits?Are there environmental limits? Resource experts believe that the Resource experts believe that the

greatest danger from increasing greatest danger from increasing consumption of nonrenewable consumption of nonrenewable resources is environmental damage resources is environmental damage caused by extraction and processing.caused by extraction and processing.

More accessible and high-grade ores More accessible and high-grade ores are exploited firstare exploited first

It takes more $ to exploit the deeper It takes more $ to exploit the deeper ores, causing more environmental ores, causing more environmental effectseffects

Will there be enough mineral Will there be enough mineral resources?resources?

Future of nonrenewable minerals depends on: actual supply and rate at which supply is used

Economic depletion: cost more to find, extract, transport and process than it’s worth

Depletion time: time it takes to use up a 80% of nonrenewable resource

Supplies of mineral resources

Reserve-to-production ratio: number of years that reserves of a NM will last

Materials revolution: new materials (ceramics and plastics) are being developed as replacements for metals

Substitutes cannot be found for many mineral resources

Mined coal

Pipeline

Pump

Oil well

Gas well

Oil storage

CoalOil and Natural Gas Geothermal EnergyHot waterstorage

Contourstrip mining

PipelineDrillingtower

Magma

Hot rock

Natural gasOil

Impervious rock

Water Water

Oil drillingplatformon legs

Floating oil drillingplatform

Valves

Undergroundcoal mine

Water is heatedand brought upas dry steam or

wet steam

Waterpenetratesdownthroughtherock

Area stripmining

Geothermalpower plant

Coal seam

Energy usage

99% of the energy used to heat the earth and our buildings comes from the sun

Without this input, earth would be -400 degrees F!

The other 1%?

…is commercial energy: from extracting and burning nonrenewable mineral resources from earth’s crust (mainly, fossil fuels-oil, natural gas, coal)

A typical citizen of the US uses 65-140x as much energy per day as a hunter-gatherer

Primitive

Hunter–gatherer

Earlyagricultural

Advancedagricultural

Earlyindustrial

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

Oil

Use of oil climbs by 1%/year Projected to peak between 2010 and 2030

and then begin to decline Natural gas is increasing by 2%/year;

cleanest and least disrupting of the 3 fossil fuels

Biomass: main source for heating in developing countries; renewable energy (fuelwood) BUT fuelwood shortage is a problem

What is oil? Petroleum (crude oil): thick liquid with

hundreds of hydrocarbons with sulfur, nitrogen, and oxygen impurities

Called “oil” when it comes out of the ground

Fossil fuel Produced by the decomposition of dead

plant matter that was 1) buried under lake and ocean sediments millions of years ago and 2) subjected to high temp and pressure for millions of years in the carbon cycle.

How is oil extracted?

Deposits are trapped under the earth’s crust on land or under the seafloor in rock formations

Well is drilled Oil is pumped out of the rock pores Transported to refinery by pipeline, truck,

or oil tanker (ship) and separated into different types

Drilling always involves: 1) some oil spills 2) use of nonrenewable resource

Diesel oil

Asphalt

Greaseand wax

Heating oil

Aviation fuel

Gasoline

Gases

Furnace

Heatedcrude oil

Who has the world’s oil supplies?

Oil reserves: identified deposits where oil can be extracted

Saudi Arabia has most oil reserves: 26%, then Iraq, Kuwait, Iran (each with about 10%)

3% in U.S.

Oil in U.S.

3% of all oil reserves in U.S. 25% from offshore drilling 17% from Alaska’s North Slope Currently, 93% of offshore drilling

comes from Gulf of Mexico

MEXICO

UNITED STATES

CANADA

PacificOcean

AtlanticOcean

GrandBanks

Gulf ofAlaska

Valdez

ALASKABeaufort

Sea

Prudhoe Bay

ArcticOcean

Coal

Gas

Oil

High potentialareas

Prince WilliamSound

Arctic National Wildlife Refuge

Trans Alaskaoil pipeline

How long will oil supplies last?

We are currently running out of oil Supplies decline when 1) demand

exceeds production and 2) other energy resources become more environmentally acceptable substitutes

Production expected to peak between 2010 and 2030

Continued…

Global reserves will last about 50 years at current usage rate

U.S. reserves will last about 10-20 years at current usage rate

U.S. oil supplies are projected to be 80% depleted within 10-15 years

TEXAS

LOUISIANA

MISSISSIPPI ALABAMA GEORGIA

FLORIDA

GULF OF MEXICO

Active drilling sites

Natural Gas

Mixture of methane, propane, butane, highly toxic hydrogen sulfide

Conventional natural gas: lies above oil reserves, formed from fossils of plants (like oil), buried deep in seafloor

Unconventional natural gas: found by itself in other underground sources (ex. Small bubbles trapped in ice crystals under arctic permafrost)—very expensive to remove, but technology being developed

Who has natural gas supplies?

Russia and Kazakhstan: 42% Other countries with large reserve:

Iran, Saudi Arabia, Algeria, U.S. (3%) Geologists expect to find more

natural gas reserves In U.S. natural gas reserves are

located in same place as crude oil

Advantages Disadvantages

Good fuel forfuel cells andgas turbines

Low land use

Easily transportedby pipeline

Moderate environ-mental impact

Lower CO2 emissions thanother fossil fuels

Less air pollutionthan otherfossil fuels

Low cost (withhuge subsidies)

High net energyyield

Ample supplies(125 years)

Sometimes burned off andwasted at wellsbecause of lowprice

Shipped acrossocean as highlyexplosive

Methane(a greenhouse gas) can leakfrom pipelines

Releases CO2

when burned

Nonrenewableresource

Difficult to transferfrom one countryto another

Requirespipelines

How long will natural gas supplies last?

Globally, 120 years at current consumption rate

In U.S., 60-75 years at current consumption rate

Pros and Cons?

Natural gas systems (combustion turbines bolted to the ground):

1) produce electricity more efficiently than burning oil or nuclear power

2) Produce much less carbon dioxide 3) Provide backup for solar and wind

power

How much do we use natural gas?

Used in 53% of U.S. homes for heat 16% of U.S. electricity By 2020, it will be 32% of U.S.

electricity

FrackingFracking Drill into reservoir rock formations. Drill into reservoir rock formations. The energy from the injection of a highly-The energy from the injection of a highly-

pressurized fracking fluid creates new pressurized fracking fluid creates new channels in the rockchannels in the rock

This increases the extraction rates and This increases the extraction rates and the recovery of fossil fuelsthe recovery of fossil fuels

Can cause leak of natural gas into Can cause leak of natural gas into groundwater—very toxic!groundwater—very toxic!

Requires TONS of water, carcinogenic Requires TONS of water, carcinogenic chemicals, etc.chemicals, etc.

What is COAL?

Solid fossil fuel formed in several stages as buried remains of plants (300-400 mill years ago) were subjected to high heat and pressure

Coal contains: sulfur, trace amts of mercury and radioactive materials

Anthracite is the most desirable form of coal because of low sulfur content and high heat

How is it extracted? Some is extracted underground by miners

working in tunnels Area strip mining: when coal lies close to

the earth’s surface on flat terrain Contour strip mining: when coal lies close

to the earth’s surface on hilly terrain Transported to processing plant where it is

broken up, crushed, and washed to remove impurities

Dried and shipped to power plants and industrial plants

Where are the largest coal supplies?

Coal provides 21% of the world’s energy

Burned to generate 62% of the world’s electricity

66% of the world’s coal reserves are in U.S., Russia, China, and India.

Half of the global coal consumption takes place in China and U.S.

How long will coal supplies last?

Coal is the world’s most abundant fossil fuel

Reserves should last at least 220 years

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 decayedplant matter in swampsand bogs; low heatcontent

Low heat content;low sulfur content;limited supplies inmost areas

Extensively usedas a fuel becauseof its high heat contentand large supplies;normally has ahigh sulfur content

Highly desirable fuelbecause of its highheat content andlow sulfur content;supplies are limitedin most areas

Advantages Disadvantages

Low cost

High net energyyield

Ample supplies(220–895 years)

Releases radioactive particles and mercury into air

High CO2 emissionswhen burned

Severe threat tohuman health

High land use (including mining)

Severe land disturbance, air pollution, andwater pollution

Very high environmentalimpact

Mining andcombustiontechnologywell-developed

Air pollution canbe reduced withimprovedtechnology (butadds to cost)

Nuclear Power

U.S. companies started developing nuclear power plants in the 1950s because:

1. Atomic Energy Commission promised nuclear power would produce electricity at much lower cost

2. Government paid ¼ of the cost of building first group of reactors

3. Price-Anderson Act: protects industry from public liability in case of accidents

Front end Back end

Uranium mines and millsOre and ore concentrate (U3O8)

Geologic disposalof moderate-and high-levelradioactive wastes

High-levelradioactivewasteUranium tailings

(low level but long half-life)

Conversion of U3O8

to UF6

Processeduranium ore

Uranium-235 as UF6

Enrichment UF6

EnrichedUF6

Fuel fabrication

Spent fuelreprocessing

Plutonium-239as PuO2

(conversion of enriched UF6 to UO2

and fabrication of fuel assemblies)

Fuel assemblies Reactor Spent fuel assemblies

Interim storageunder water

Open fuel cycle today

Prospective “closed” end fuel cycle

Decommissioningof reactor

Decommissioningof reactor

Spent fuelassembliesSpent fuelassemblies

Nuclear Fuel Cycle

Figure 15-37Page 368

Operational

Decommissioned

Proposed high levelnuclear waste storage site

Reactors

1

2

Low risk of accidents because of multiple safety systems

Moderate land use

Moderate landdisruption andwater pollution

Emits 1/6 asmuch CO2 as coal

Lowenvironmentalimpact (withoutaccidents)

Large fuelsupply

Spreads knowledge and technology for building nuclear weapons

No acceptable solution for long-term storage of radioactive wastes

Catastrophic accidents can happen

High environmental impact (with major accidents)

Low net energy yield

High cost

Advantages Disadvantages

Nuclear Power

Coal

Ample supply

High net energyyield

Very high airpollution

High CO2

emissions

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

High land disruption fromsurface mining

High land use

Low cost)

Nuclear

Ample supplyof uranium

Low net energyyield

Low air pollution

Low CO2

emissions

About 6,000deaths per year in U.S.

Much lower landdisruption fromsurface mining

Moderate land use

High cost)

COAL vs. NUCLEAR POWER

What should we do with high-level radioactive waste?

Proposals:1. Bury it deep underground (not sure

about long-term behavior of sites)2. Shoot it into space or into the sun (very

high cost and if accident occurred, waste could be dispersed all over earth)

3. Bury it under ice caps (long-term stability of ice caps is not known)

4. Dump it into deep ocean (waste might be spewed out somewhere else by volcanic activity)

Connection between nuclear reactors and spread of nuclear weapons?

60 countries (1 out of 3) have nuclear weapons or knowledge to build them

Info for this has come mostly from the U.S. which has been selling in international marketplace

Bad news: enough nuclear weapons to kill everyone in the world 30x

“dirty bombs”: dynamite mixed with radioactive material (easy to obtain-stolen from loosely-guarded sources)

Sources: hospitals, research labs, industries, smoke detectors