ENVIRONMENTAL EFFECTS OF USING MINERAL RESOURCES The extraction, processing, and use of mineral...

ENVIRONMENTAL EFFECTS OF USING MINERAL RESOURCES

The extraction, processing, and use of mineral resources has a large environmental impact.

Figure 15-9Figure 15-9

Fig. 15-10, p. 344

Natural Capital Degradation

Extracting, Processing, and Using Nonrenewable Mineral and Energy Resources

StepsSteps Environmental effectsEnvironmental effects

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

Exploration, extraction

Processing

Solid wastes; radioactive material; air, water, and soil pollution; noise; safety and health hazards; ugliness; heat

Transportation, purification, manufacturing

Use

Noise; ugliness; thermal water pollution; pollution of air, water, and soil; solid and radioactive wastes; safety and health hazards; heat

Transportation or transmission to individual user, eventual use, and discarding

Costs Ownership costs – equipment, labor, safety

(insurance), environmental costs (reclamation, pollution control, air monitors, water treatment, etc.), taxes

External costs – processing the resource, transporting the resource

Marginal costs – research: finding new sources of the resource and new ways to harvest it

Harvesting Nonrenewable Resources

Benefits Direct – money received for resources;

provides many jobs Indirect – land can be reclaimed

(brought back to original condition) and sold for profit.

ENVIRONMENTAL EFFECTS OF USING MINERAL RESOURCES

Minerals are removed through a variety of methods that vary widely in their costs, safety factors, and levels of environmental harm.

A variety of methods are used based on mineral depth. Surface mining: shallow deposits are removed. Subsurface mining: deep deposits are removed.

Methods Surface Mining

Description – if resource is <200 ft. from the surface, the topsoil is removed (and saved), explosives are used to break up the rocks and to remove the resource, reclamation follows

Benefits – cheap, easy, efficient Costs – tears up the land (temporarily), byproducts

produce an acid that can accumulate in rivers and lakes

Methods (Continued) Underground Mining

Description – digging a shaft down to the resource, using machinery (and people) to tear off and remove the resource

Benefits – can get to resources far underground Costs – more expensive, more time-consuming,

more dangerous

Methods (Continued)

Reclamation Description – returning the rock layer

(overburden) and the topsoil to a surface mine, fertilizing and planting it

Benefits – restores land to good condition Costs – expensive, time-consuming

Specific Resources & Their Uses Coal – formed from ancient peat bogs (swamps) that

were under pressure as they were covered. Used for electricity, heat, steel, exports, and industry,

may contribute to the “Greenhouse Effect” Four types of coal exist: lignite (soft, used for

electricity), bituminous and subbituminous (harder, also used for electricity) and anthracite (hardest, used for heating)

50% of all the coal is in the United States, the former Soviet Union and China

Specific Nonrenewable Resources

Open-pit Mining Machines dig

holes and remove ores, sand, gravel, and stone.

Toxic groundwater can accumulate at the bottom.


Area Strip Mining Earth movers strips away overburden, and giant shovels removes mineral deposit.

Often leaves highly erodible hills of rubble called spoil banks.


Contour Strip Mining Used on hilly or

mountainous terrain.

Unless the land is restored, a wall of dirt is left in front of a highly erodible bank called a highwall.


Mountaintop Removal Machinery removes

the tops of mountains to expose coal.

The resulting waste rock and dirt are dumped into the streams and valleys below.


Fig. 15-18, p. 351

Solutions

Sustainable Use of Nonrenewable Minerals

• Do not waste mineral resources.

• Recycle and reuse 60–80% of mineral resources.

• Include the harmful environmental costs of mining and processing minerals in the prices of items (full-cost pricing).

• Reduce subsidies for mining mineral resources.

• Increase subsidies for recycling, reuse, and finding less environmentally harmful substitutes.

• Redesign manufacturing processes to use less mineral resources and to produce less pollution and waste.

• Have the mineral-based wastes of one manufacturing process become the raw materials for other processes.

• Sell services instead of things.

• Slow population growth.

Specific Resources & Their Uses Limestone – abundant locally, formed from layers of

seashells and organisms under pressure as they were covered; used in sidewalks, fertilizers, plastics, carpets, and more

Lead – used in batteries and cars Clay – used to make books, magazines, bricks, and

linoleum Gold – besides being used as money and for jewelry,

gold is used in medicine (lasers, cauterizing agents) and in electronics (circuits in computers, etc.)

Texas

Central – limestone, tin, clay, lead, garnets, freshwater pearls, amethysts, calcium carbonate

West – talc, mercury, silver, petroleum, sulfur East – lignite coal, petroleum South – lignite coal, petroleum, uranium, limestone North – helium, uranium, petroleum, bituminous

coal

United States Central – diamonds (Arkansas), bituminous

coal West – bituminous and subbituminous coal,

gold, silver, copper East – anthracite coal, bituminous coal South – some gold (SC), bituminous coal North – bituminous coal, some gold (SD, WI)

Primary Sources

Definition – the original sources that are used to make electricity or heat

Energy Resources

Secondary Sources Definition – the heat and

electricity that we use for energy

Cogeneration Production of two useful forms of energy,

such as high-temperature heat or steam and electricity, from the same fuel source.

Ex. An industry using natural gas for manufacturing and using the waste heat to produce electricity.

Fossil Fuels Energy conversion – chemical to electrical, heat or

mechanical Only about 30% efficient Benefits – easy to use, currently abundant Costs – a nonrenewable resource, produces pollutants

that contribute to acid rain and the greenhouse effect Oil- Supplies the most commercial energy in the

world today. People in the U.S. use 23 barrels of petroleum per person or 6 billion barrels total each year!!!

Examples of Primary Sources

Core Case Study: How Long Will the Oil Party Last?

Saudi Arabia could supply the world with oil for about 10 years.

The Alaska’s North Slope could meet the world oil demand for 6 months (U.S.: 3 years).

Alaska’s Arctic National Wildlife Refuge would meet the world demand for 1-5 months (U.S.: 7-25 months).

OIL Crude oil (petroleum) is a thick liquid containing

hydrocarbons that we extract from underground deposits and separate into products such as gasoline, heating oil and asphalt. Only 35-50% can be economically recovered from a

deposit. As prices rise, about 10-25% more can be recovered

from expensive secondary extraction techniques. This lowers the net energy yield.

OIL Refining crude oil:

Based on boiling points, components are removed at various layers in a giant distillation column.

The most volatile components with the lowest boiling points are removed at the top.


Fig. 16-5, p. 359

Gases

Gasoline

Aviation fuel

Heating oil

Diesel oil

Naptha

Grease and wax

Asphalt

Heated crude oil

Furnace

OIL Eleven OPEC (Organization of Petroleum

Exporting Countries) have 78% of the world’s proven oil reserves and most of the world’s unproven reserves.

After global production peaks and begins a slow decline, oil prices will rise and could threaten the economies of countries that have not shifted to new energy alternatives.

Case Study: U.S. Oil Supplies The U.S. – the world’s largest oil user – has

only 2.9% of the world’s proven oil reserves.

U.S oil production peaked in 1974 (halfway production point).

About 60% of U.S oil imports goes through refineries in hurricane-prone regions of the Gulf Coast.

Heavy Oils from Oil Sand and Oil Shale: Will Sticky Black Gold Save Us? Heavy and tarlike oils from oil sand and oil shale

could supplement conventional oil, but there are environmental problems. High sulfur content. Extracting and processing produces:

Toxic sludge Uses and contaminates larges volumes of water Requires large inputs of natural gas which reduces net

energy yield.

Oil Shales

Oil shales contain a solid combustible mixture of hydrocarbons called kerogen.


Core Case Study: How Long Will the Oil Party Last?

We have three options: Look for more oil. Use or waste less oil. Use something else.

Estimated that oil will last another 42-93 years


NATURAL GAS Natural gas, consisting mostly of methane, is

often found above reservoirs of crude oil. When a natural gas-field is tapped, gasses are

liquefied and removed as liquefied petroleum gas (LPG).

Coal beds and bubbles of methane trapped in ice crystals deep under the arctic permafrost and beneath deep-ocean sediments are unconventional sources of natural gas.

NATURAL GAS Russia and Iran have almost half of the

world’s reserves of conventional gas, and global reserves should last 62-125 years.

Natural gas is versatile and clean-burning fuel, but it releases the greenhouse gases carbon dioxide (when burned) and methane (from leaks) into the troposphere.

COAL

Coal is a solid fossil fuel that is formed in several stages as the buried remains of land plants that lived 300-400 million years ago.


Fig. 16-12, p. 368

Increasing heat and carbon content

Increasing moisture content

Peat (not a coal)

Lignite (brown coal)

Bituminous

(soft coal)

Anthracite

(hard coal)Heat Heat Heat

Pressure Pressure Pressure

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. 16-13, p. 369

Waste heat

Coal bunker TurbineCooling tower

transfers waste heat to

atmosphere

Generator

Cooling loop

Stack

Pulverizing mill

Condenser Filter

Boiler

Toxic ash disposal

COAL Coal reserves in the United States, Russia,

and China could last hundreds to over a thousand years. The U.S. has 27% of the world’s proven coal

reserves, followed by Russia (17%), and China (13%).

In 2005, China and the U.S. accounted for 53% of the global coal consumption.

TYPES OF ENERGY RESOURCES About 99% of the energy we use for heat comes

from the sun and the other 1% comes mostly from burning fossil fuels. Solar energy indirectly supports wind power,

hydropower, and biomass. About 76% of the commercial energy we use

comes from nonrenewable fossil fuels (oil, natural gas, and coal) with the remainder coming from renewable sources.

TYPES OF ENERGY RESOURCES

Nonrenewable energy resources and geothermal energy in the earth’s crust.


Fig. 16-2, p. 357

Oil and natural gasOil and natural gasFloating oil drilling

platform Oil storage CoalCoalContour strip miningOil drilling

platform on legs

Geothermal Geothermal energyenergy

Hot water storageOil well

Pipeline Geothermal power plant

Gas well Valves Mined coal

Pump Area strip mining Drilling

tower

Pipeline

Impervious rock

Underground coal mineNatural gasWaterOil

Water is heated and brought up as dry

steam or wet steamWater

Coal seam Hot rock

Water penetrates

down through the rock

Magma

TYPES OF ENERGY RESOURCES

Commercial energy use by source for the world (left) and the U.S. (right).


REDUCING ENERGY WASTE AND IMPROVING ENERGY EFFICIENCY

Four widely used devices waste large amounts of energy: Incandescent light bulb: 95% is lost as heat. Internal combustion engine: 94% of the energy in its

fuel is wasted. Nuclear power plant: 92% of energy is wasted through

nuclear fuel and energy needed for waste management. Coal-burning power plant: 66% of the energy released

by burning coal is lost.

USING RENEWABLE SOLAR ENERGY TO PROVIDE HEAT AND ELECTRICITY

A variety of renewable-energy resources are available but their use has been hindered by a lack of government support compared to nonrenewable fossil fuels and nuclear power. Direct solar Moving water Wind Geothermal


The European Union aims to get 22% of its electricity from renewable energy by 2010.

Costa Rica gets 92% of its energy from renewable resources.

China aims to get 10% of its total energy from renewable resources by 2020.

In 2004, California got about 12% of its electricity from wind and plans to increase this to 50% by 2030.


Denmark now gets 20% of its electricity from wind and plans to increase this to 50% by 2030.

Brazil gets 20% of its gasoline from sugarcane residue.

In 2004, the world’s renewable-energy industries provided 1.7 million jobs.

Solar Types – photovoltaic cells (convert sunlight directly to

electricity with a 10% efficiency) and solar thermal systems (sun’s heat is used to heat bodies of water enough to produce steam that can be used to make electricity)

Energy conversion – radiant/heat to electrical, heat or mechanical

Benefits – pollution-free, unlimited source Costs – not useful in cloudy areas or at night, we do

not have the technology needed to use very efficiently

Producing Electricity with Solar Cells

Photovoltaic (PV) cells can provide electricity for a house of building using solar-cell roof shingles.


Fig. 17-17, p. 398

Single solar cellSolar-cell roof

–

Boron enriched silicon

+

Junction

Phosphorus enriched silicon

Roof options

Panels of solar cells

Solar shingles

Producing Electricity with Solar Cells

Solar cells can be used in rural villages with ample sunlight who are not connected to an electrical grid.


Core Case Study: The Coming Energy-Efficiency and Renewable-Energy Revolution

It is possible to get electricity from solar cells that convert sunlight into electricity. Can be attached like shingles on a roof. Can be applied to window glass as a coating. Can be mounted on racks almost anywhere.

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