Encyclopedia of Global Resources part 25 pot

Clean Air Act Categories: Laws and conventions; government and resources Dates: 1963, rewritten in 1970, amended in later years The Clean Air Acts of 1963 and 1970, with subse-quent ame

Manning, D A C Introduction to Industrial Minerals.

New York: Chapman & Hall, 1995

Meunier, Alain Clays Translated by Nathalie Fradin.

New York: Springer, 2005

Murray, Haydn H Applied Clay Mineralogy: Occurrences,

Processing, and Application of Kaolins, Bentonites,

Palygorskite-Sepiolite, and Common Clays Boston:

Elsevier, 2007

Newman, A C D., ed Chemistry of Clays and Clay

Min-erals Harlow, England: Longman for

Mineralogi-cal Society, 1986

Web Sites

Natural Resources Canada

Canadian Minerals Yearbook, Mineral and Metal

Commodity Reviews

http://www.nrcan-rncan.gc.ca/mms-smm/busi-indu/cmy-amc/com-eng.htm

U.S Geological Survey

Clays: Statistics and Information

http://minerals.usgs.gov/minerals/pubs/

commodity/clays

See also: Ceramics; Chlorites; Open-pit mining;

Pa-per; Residual mineral deposits; Sedimentary

pro-cesses, rocks, and mineral deposits; Silicates; United

States

Clean Air Act

Categories: Laws and conventions; government

and resources

Dates: 1963, rewritten in 1970, amended in later

years

The Clean Air Acts of 1963 and 1970, with

subse-quent amendments, are intended to improve air

qual-ity in the United States, largely through mandated air

quality standards.

Background

The 1963 Clean Air Act (CAA) and its 1965

amend-ments attempted to improve air quality in the United

States through federal support of air pollution

re-search and aid to states in establishing air pollution

control agencies The 1970 CAA provided for national

air-quality standards by specifying maximum

permissi-ble ambient air concentrations for pollutants deemed harmful to human health and the environment The deadline for the enforcement of the primary stan-dards was set for 1982 but was later extended

Provisions The CAA provided that the Environmental Protec-tion Agency (EPA), established in 1970, was to set pol-lution standards for new plants and that states were to create state implementation plans for enforcement

Time Line of U.S Clean Air Acts

1955 Air Pollution Control Act

First U.S law addressing air pollution and funding research into pollution prevention

1963 Clean Air Act

of 1963

First U.S law providing for monitoring and control of air pollution

1967 Air Quality Act Established

enforcement provisions

to reduce interstate air pollution transport

1970 Clean Air Act Extension

of 1970

Established first comprehensive emission regulatory structure, including the National Ambient Air Quality Standards (NAAQS)

1977 Clean Air Act Amendment

of 1977

Provided for the prevention of deterioration in air quality in areas that were in compliance with the NAAQS

1990 Clean Air Act Amendment

of 1990

Established programs to control acid

precipitation, as well as

189 specific toxic pollutants

Source: U.S Environmental Protection Agency.

The country was divided into 247 Air Quality Control

Regions for enforcement purposes Finally, the CAA

mandated pollution standards for automobiles and

trucks with specified deadlines for achievement;

Con-gress, however, repeatedly waived the deadlines The

1970 CAA and the 1977 amendments have been

suc-cessful in reducing several ambient air pollutants,

most notably carbon monoxide, lead, and suspended

particulates However, ozone, nitrogen dioxide,

vola-tile organic compounds, and sulfur dioxide remain at

high levels in many areas

The 1990 amendments to the CAA were so

far-ranging as to constitute a rewriting of the act The

1990 amendments displayed an awareness of

develop-ing problems such as acid deposition and

strato-spheric ozone (Titles IV and VI) Title I provided a

new enforcement scheme with specific categories for

cities (Los Angeles is in a category by itself) for

reach-ing pollution standards for ozone, carbon monoxide,

and particulates, with a twenty-year deadline for

com-pliance Title II provided specific standards for

mo-bile source pollution with deadlines for compliance

Title III established emission limits for hazardous or

toxic air pollutants with numerous deadlines for

en-forcement An innovative aspect of Title IV was the

es-tablishment of a process of emissions trading whereby

the most polluting utilities could acquire the excess

pollution capacity of less-polluting utilities The goal

was to reduce progressively the total amount of sulfur

dioxide emitted in the United States through the

op-eration of market forces

Impact on Resource Use

The CAA has been explicitly directed toward

improv-ing human health Implicit in the CAA is a concern

for the environment and the impact of air pollution

on natural resources Efforts to deal with acid

deposi-tion, for example, display a concern for the impact of

sulfur dioxide on water and forest products The

im-plementation of automobile emission standards has

had a positive effect on oil consumption

The overall thrust of the Clean Air Act has been

“technology-forcing”; in other words, industries have

been forced to develop improved technologies to

meet mandated standards The results of this

ap-proach have been mixed in urban areas Some

im-provement in air quality has certainly occurred

Nonetheless, costs have escalated for full

achieve-ment of the various standards of the CAA

John M Theilmann

See also: Acid precipitation; Air pollution and air pollution control; Environmental Protection Agency; Ozone layer and ozone hole debate

Clean Water Act

Categories: Laws and conventions; government and resources

Date: Signed October 2, 1965

The Federal Water Quality Act of 1965, commonly known as the Clean Water Act, required states to set quality standards based on a waterway’s usage It proved to be a crucial step in the protection of the coun-try’s water supply.

Background

“No one has a right to use America’s rivers and Amer-ica’s waterways, that belong to all the people, as a sewer.” With those words, President Lyndon Johnson signed the Federal Water Quality Act of 1965 and placed in motion steps to curtail pollution of the na-tion’s water The fight to stop water pollution began in colonial times, when local laws prohibited dumping

in major waterways However, a national water policy was lacking until passage of the 1948 Federal Water Pollution Control Act Concerned with the health ef-fects of water pollution, the law allowed legal inter-vention against polluters and provided funding for the development of sewage-treatment plants Despite subsequent amendments furthering its cause, this act failed to provide a strong defense against polluters

In a February 8, 1965, speech, President Johnson stated, “Every major river and waterway is now pol-luted,” and he implored the nation to stop the de-struction Pollution stemmed from municipal waste, industrial waste, and runoff from agricultural land Each contained a wide variety of polluting agents and contributed to a massive problem that some feared would eventually contaminate the country’s entire water supply

Provisions The Federal Water Quality Act, or Clean Water Act, provided guidelines by which states could fight water pollution First, states were to define each waterway,

in whole or in part, by its dominant usage: water sup-ply, recreational, industrial, fish and wildlife

tion, or agricultural Second, states were to set water

quality standards based on that primary usage If

states failed to comply by June 30, 1967, or set

inade-quate standards, the Department of Health,

Educa-tion, and Welfare (HEW) would be required to set the

quality standard The hope was to prevent pollution

before it occurred The standards could be used to

support legal actions against municipal, industrial, or

individual offenders The act also created the Water

Pollution Control Administration under HEW, which

was to have responsibility for enforcing the act

Even-tually water quality came under Environmental

Pro-tection Agency control

Impact on Resource Use

In 1970, the 1948 and 1965 acts were combined to

cre-ate a strong national wcre-ater policy Further amended

in 1972, this policy called for stricter standards and

heightened enforcement to make all navigable waters

fishable and swimmable by 1983 Although that

dead-line was subsequently abandoned, keeping water clean

enough to meet the fishable and swimmable

stan-dards remained the national goal As water testing

technology improved, the Clean Water Act (as all

water quality-related acts have collectively been called

beginning in 1972) strengthened the guidelines for

water purity and protection These acts were

success-ful in reducing and eliminating contaminants in the

nation’s water resources

Jennifer Davis

See also: Clean Air Act; Environmental Protection

Agency; Thermal pollution and thermal pollution

control; Water pollution and water pollution control

Clear-cutting

Category: Obtaining and using resources

At one time a standard practice in lumbering,

clear-cutting has become one of the most controversial

har-vesting techniques used in modern logging.

Definition

Clear-cutting is the practice of cutting all the trees on

a tract of land at the same time A tract that has been

clear-cut will have no trees left standing With its

wind-rows of slash (the unmarketable portions of the tree,

such as tops and branches) and debris, a clear-cut tract of land may appear to the untrained eye as though a catastrophic event has devastated the land-scape As far as critics of clear-cutting are concerned, that is indeed what has happened

Overview The commercial forest industry is frequently de-nounced for damaging the environment through clear-cutting, particularly when clear-cutting is used

to harvest timber on a large scale Clear-cutting steep hillsides can leave the land susceptible to erosion, as the removal of all trees leaves nothing to slow the flow

of rainfall Clear-cut hillsides can lose topsoil at a rapid rate, choking nearby streams with sedimenta-tion and killing aquatic species, such as trout and sal-mon The large amounts of slash or debris left behind can pose a fire hazard Wildlife studies have also indi-cated that certain species of birds and mammals are threatened when their habitats are clear cut, as they either lose their nesting area or are exposed to in-creased risk from predators The northern spotted owl, for example, becomes easy prey for great horned owls when it is forced to fly across large open areas Representatives of the timber industry counter such criticisms by noting that, for some species of trees, selective harvesting simply does not work Many species of trees will not regenerate in shaded areas In addition, selective harvesting, or cutting only a lim-ited number of trees from a stand, can also be ecologi-cally damaging Logging may create stress on the re-sidual standing timber, leading to disease and die-off

of the uncut trees, while the operation of mechanized equipment can be as disrupting to nesting and forag-ing habits of wildlife as clear-cuttforag-ing the stand would have been

Loggers further argue that criticisms of clear-cut-ting are often based on irrational considerations such

as aesthetics—the public dislikes clear-cuts because they are ugly—rather than on sound silvicultural or ecological principles Nonetheless, in many areas the timber industry has modified harvesting practices in response to public pressures and government con-cerns Rather than clearing tracts of land in large rect-angular blocks, many woods workers now cut off irreg-ularly shaped strips that are considerably smaller in size than before Patches of standing timber are left in clear-cut areas to provide cover for wildlife, and slash

is chipped and spread as mulch to reduce the risk of brush fires Buffer zones, or strips of uncut timber, are

left along stream banks and near lakes to slow or

pvent runoff from the clear-cut areas Clear-cutting

re-mains an appropriate harvesting method in certain

situations, as in cutting even-age stands of

plantation-grown trees, but modifications in its application can

help prevent damage to the environment

Nancy Farm Männikkö

See also: Forest management; Forestry; Forests;

Tim-ber industry; Wood and timTim-ber

Climate and resources

Categories: Ecological resources; environment,

conservation, and resource management

Climate is the average of weather conditions at a place

or in a region, usually recorded as both the mean

(aver-age) and the extremes of temperature, precipitation,

and other relevant conditions Resources are the

fac-tors and characteristics of the natural environment that people find useful, including climate, land, soil, water, minerals, and wild vegetation Thus, climate is itself a natural resource, and it interacts with or affects the character or quality of other resources and their ex-ploitation or development.

Background Climate can be seen as the most basic or primary of natural resources in that it affects other resources to a greater degree than it is affected by them Perhaps the best evidence of this is in the nature and distribution

of wild vegetation (The term “wild vegetation” is pref-erable to “natural vegetation” because humankind has had dramatic impacts upon the character and dis-tribution of plants.) Temperature, moisture, and so-lar radiation are the major factors determining the plant species that will grow in a region, and the major global vegetation types (forest, shrub, grassland, desert, and tundra) reflect climatic controls Microcli-mates are in turn created within the vegetation: trees provide shade and thus a slightly cooler temperature

A clear-cut mountainside in Canada (©Charles Dyer/Dreamstime.com)

than in the surrounding region However,

micromates exist only in minuscule portions of the main

cli-matic region; consequently, climate influences

vege-tation more than the reverse

Solar radiation is the source of energy that drives

the Earth’s atmosphere and its circulation system;

therefore it is the basic element in determining

differ-ences in climate The sun’s rays are vertical at some

time of the year only in the tropics, between the

Tropic of Cancer (23.5° north latitude) and the Tropic

of Capricorn (23.5° south latitude) These lines

deter-mine where the greatest heat supply is found; regions

poleward of about 40° north and south latitudes

actu-ally have a net loss of reradiation to outer space and

depend upon a heat supply from the tropics, which

is carried poleward by the general circulation of the

atmosphere

Equatorial Climates

The general circulation is the average of wind flow at

the surface of the Earth and is driven by the surplus of

solar radiation in the tropics By definition, tropical

climates do not experience freezing temperatures,

have the least variation in length of day, and

conse-quently experience the least “seasonality” of any

lati-tudes Seasons here are characterized more by

precip-itation contrasts—“dry” and “wet”—rather than by

summer and winter temperatures The greatest

com-bination of heat and moisture resources on the Earth’s

surface, especially important in creating the

condi-tions under which the tropical rain forest flourishes,

is near the equator

Rates of weathering of bedrock and soils are

great-est in the equatorial region, because weathering is a

function of the availability of heat and moisture It

fol-lows that the depth to which rock and soils are

weath-ered and leached (mineral plant foods dissolved and

removed by groundwater flow) is greater here than

elsewhere on the Earth’s surface Continuous high

temperatures work against carbon storage in the soils;

organic carbon storage requires recycling from wild

vegetation Oxidation of organic matter by exposure

to the sun’s rays follows the clearing of tropical forests

Under wild vegetation conditions, where the rain

for-est canopy protects soils from raindrop impact,

ero-sion rates are not as high as one would expect from

the intense rain showers However, on sloping land,

the soils become saturated and flow downslope, often

catastrophically in disastrous landslides Where wild

vegetation has been removed by human activity, in

farming or especially in urban centers, erosion and mass wasting (landslides) are exacerbated during rainy seasons and cause considerable loss of life and property damage

With increasing distance from the equator, the trop-ics experience more pronounced seasons, particularly

in moisture resources Precipitation totals decline, and drought risk increases Dry seasons are expected annu-ally because of the shifting of the general circulation

of the atmosphere The timing and extent of this shift determine whether a region experiences drought (a period when significantly lower-than-average precipi-tation causes low levels of streamflow and increased stress on vegetation, both wild and cultivated) East and South Asia are most affected by shifting atmo-spheric circulation and the resultant wet and dry sea-sons, or “monsoons.” Africa also has pronounced wet and dry seasons as a result of shifting atmospheric cir-culation patterns; droughts in the Sahel and East Af-rica are a consequence of the failure of rains to reach the region in time to support agriculture and grazing Droughts in this part of the world result in famine: An estimated one million persons died in the Sahelian droughts of the late 1960’s and 1970’s Thus climate must be defined in terms of both averages and ex-tremes; the latter result in hazards that have dire con-sequences for the inhabitants of the affected region The probability of a drought hazard occurring in-creases as precipitation averages decrease (an inverse relationship) and is exacerbated by the fact that most tropical rainfall falls as intense thundershowers, which are spatially highly variable One farm may be drenched by rain while its neighbors continue to be tormented by drought In addition to drought risk on the margins of the tropics, the major climatic hazard

is the tropical cyclone, which goes by various names, most commonly hurricane or typhoon These cy-clones, too, rarely affect the equatorial zone but fre-quent the tropical transition to the subtropics and midlatitudes Movement of tropical cyclones is east-erly in their early and middle stages, following the general circulation known as the trade winds

The Subtropics The types of climates that exist poleward of the tropics depend on the side of the continent: West sides are deserts or drylands; east sides are the humid subtrop-ics, a transition zone with cooler temperatures and more risk of frost with greater distance from the equa-tor The humid subtropics are also subject to

sional easterly flow weather systems, including

tropi-cal cyclones While they represent a serious hazard,

claiming both lives and property, these easterly

sys-tems also deliver moisture and thus reduce the

possi-bility of drought The generally warm temperatures

and moist conditions make these climates some of the

most productive for crop growth, even exceeding the

potential of the tropics Leaching of soils and high

erosion rates on cleared fields are nearly as great a

problem as in the tropics, as is the rapid rate of

or-ganic decomposition

The west coast drylands, which include all the

world’s major deserts—Sahara, Atacama, Kalahari,

Australian, and North American—are a consequence

of the general circulation of the atmosphere, which

chooses these locations to make the swing from the

prevailing westerlies of the middle latitudes to the

easterly trade winds In the process, high atmospheric

pressures prevail, and winds are descending or

subsid-ing, and therefore warming—just the opposite of the

conditions required for rainfall The drylands may

ex-tend deep into the continents, as in North America

and especially in Africa and Asia; the dryness of the

Sahara also blankets the Middle East and extends

northward into Central Asia Temperatures along the

equatorward flank of these five major dryland zones

are tropical, and where irrigation water is available,

tropical plants may be grown Most of the drylands are

subtropical or midlatitude, and thus they experience

frost as well as drought hazard Weathering and

ero-sion are appreciably less in the drylands, owing to the

absence of moisture, and leaching of the soils is

virtu-ally absent Instead, salts in the soils can build up to

levels that are toxic to most plants—another

climate-related hazard

The Midlatitudes

The midlatitudes extend from the subtropics to the

polar climates of the Arctic and Antarctic, with

tem-peratures following a transition from warm on the

equatorward flank to too cold for agriculture nearer

the poles This is the realm of the westerlies, with

extratropical cyclones delivering most of the weather

It is a zone of contrasting conditions, year-by-year

and day-by-day, ranging from warmer than average to

colder than average, from too humid to too dry on

the inland dryland border

Thus the hazards of extremes of temperature and

precipitation often dominate life, as tropical and

po-lar air masses converge to create the cyclones that

march from west to east Drought risk is most impor-tant on the dryland border and results in the world’s great grasslands Summer heat may be a hazard on oc-casion, and nearly every winter brings storms with freezing rain, high winds, and heavy snowfalls, partic-ularly on the eastern sides of the continents The east-ern sides are also afflicted with such intense summer storms as the tornadoes of North America (a winter phenomenon in the adjoining humid subtropics), and the tail end of hurricanes and typhoons, as these become caught up in westerly circulation and curve poleward again The Arctic fringe of the midlatitudes

is too cool for significant agriculture but yields the great subarctic forests of Canada, Scandinavia, and Russia Polar climates are too cold for all but a few hunters and fishers and people engaged in extractive industries or scientific research

Neil E Salisbury

Further Reading

Anderson, Bruce T., and Alan Strahler Visualizing Weather and Climate Hoboken, N.J.: Wiley, in

col-laboration with the National Geographic Society, 2008

Bryson, Reid A., and Thomas J Murray Climates of Hunger: Mankind and the World’s Changing Weather.

Madison: University of Wisconsin Press, 1977

Grigg, D B The Agricultural Systems of the World: An Evo-lutionary Approach New York: Cambridge

Univer-sity Press, 1974

Le Roy Ladurie, Emmanuel Times of Feast, Times of Famine: A History of Climate Since the Year 1000 Rev.

and updated ed Translated by Barbara Bray New York: Noonday Press, 1988

Ruddiman, William F Plows, Plagues, and Petroleum: How Humans Took Control of Climate Princeton, N.J.:

Princeton University Press, 2005

Sivakumar, Mannava V K., and Raymond P Motha,

eds Managing Weather and Climate Risks in Agricul-ture New York: Springer, 2007.

Strahler, Alan H., and Arthur N Strahler Introducing Physical Geography 4th ed Hoboken, N.J.: J Wiley,

2006

Strahler, Arthur N., and Alan H Strahler Elements of Physical Geography 4th ed New York: Wiley, 1989.

See also: Agriculture industry; Atmosphere; Deserti-fication; Deserts; Drought; Dust Bowl; El Niño and La Niña; Forests; Grasslands; Monsoons; Rain forests; Weather and resources

Climate change See Greenhouse

gases and global climate change

Climate Change and Sustainable

Energy Act

Categories: Laws and conventions; government

and resources

Date: June 21, 2006

In the later part of the twentieth century and the early

part of the twenty-first century, global temperatures

have been some of the warmest ever recorded Measures

to reduce greenhouse gases and the implementation of

alternative sources of renewable energy are ways of

combating climate change The United Kingdom’s

Climate Change and Sustainable Energy Act 2006

promotes microgeneration technologies to replace

car-bon-based fuel sources.

Background

Countries in the developed world have established

initiatives to reduce greenhouse gases and combat

climate change Common greenhouse gases include

carbon dioxide, methane, nitrous oxide, and

hydro-fluorocarbons Greenhouse gases act to absorb the

Earth’s infrared radiation and increase temperatures

The Kyoto Protocol, an important climate-change

measure ratified by many industrialized countries, was

established in 1997 Some countries establish their

own greenhouse-gas emission standards For

exam-ple, the United Kingdom enacted the Sustainable

En-ergy Act of 2003 and the EnEn-ergy Act of 2004;

modifica-tions of microgeneration targets were applied to the

2006 act The Climate Change and Sustainable

En-ergy Act is a law that builds upon previous climate

change policies

Provisions

The Climate Change and Sustainable Energy Act was

enacted on June 21, 2006, in an effort to encourage

microgeneration technologies aimed at reducing

greenhouse-gas emissions Microgeneration

technol-ogies include many non-carbon-fueled energy sources

Microgeneration is the generation of electricity and

heat from a renewable energy source These sources include non-fossil fuels and nonnuclear fuels, such as biomass, biofuel, wind, water-tide, solar-power, and geothermal sources All renewable sources of fuel are useful in microgeneration This initiative of increas-ing microgeneration technologies ultimately will re-duce dependency on carbon-based energy emissions The Climate Change and Sustainable Energy Act per-mits homes to reduce dependency on carbon-based fuel sources and increase microgeneration technolo-gies Building-construction regulations are also speci-fied in this act Each year, the ministerial authorities report to Parliament the measures taken by the gov-ernment in support of this measure Local authorities have access to the reports and ensure that these mea-sures are followed at the local level This act incen-tivizes local governments to encourage the use of microgeneration and the reduction of greenhouse-gas emissions

Impact on Resource Use

A 2009 assessment by the U.S Global Change Re-search Program outlined the effect of the increase in greenhouse gases The increase of global tempera-tures could be as high as 6° Celsius by the year 2090, suggesting that climate change is real and has dra-matic impacts By the end of the twenty-first cen-tury, sea levels in U.S coastal regions may rise more than 1 meter Climate change has occurred even more rapidly in the Arctic regions, where ice is melt-ing, and the fishing industry may experience a nega-tive impact

The Climate Change and Sustainable Energy Act serves as a model for other industrialized countries For example, Germany is combating climate change with a similar law: the Renewable Energy Sources Act

Kevin D Weakley

Web Site Climate Change and Sustainable Energy Act, 2006

http://www.opsi.gov.uk/acts/acts2006/pdf/

ukpga_20060019_en.pdf See also: Agenda 21; Climate and resources; Earth Summit; Gore, Al; Greenhouse gases and global cli-mate change; Kyoto Protocol

Category: Energy resources

Where Found

While coal has been found on every principal

conti-nent of the Earth, regional distribution is restricted to

sedimentary and metamorphosed sedimentary rock

terrains of Upper Devonian age and younger (that is,

the last 365 million years of geologic history) As a

result of this geologic association, most of the coal

re-serves of the world are found in the Northern

Hemi-sphere continents of Asia, Europe, and North

Amer-ica However, there are reasonably large reserves in

Australia, South Africa, and Colombia

Primary Uses

Coal was historically used as a domestic fuel for the

heating of homes, and more than 26 percent of the

coal mined globally is a primary source of energy

Worldwide, 41 percent of coal mined is burned in

power plants, principally for the generation of

elec-tricity Another significant use is in the manufacture

of coke, an improved carbon-content derivative of

coal employed in the production of steel Lesser

amounts of coal are used in the direct heating of

homes, for a variety of industrial purposes, and,

in-creasingly, in liquefaction and gasification processes

whereby coal is converted to liquid and gaseous forms

of hydrocarbon fuels

Technical Definition

Coal is a general term encompassing a variety of

com-bustible sedimentary and metamorphic rocks

con-taining altered and fossilized terrestrial plant remains

in excess of 50 percent by weight and more than 70

percent by volume Categories of coal differ in relative

amounts of moisture, volatile matter, fixed carbon, and

degree of compaction of the original carbonaceous

material Coal is commonly termed a fossil fuel

Cate-gories of coal include peat (a coal precursor), lignite,

bituminous coal, subbituminous coal, and anthracite

Peat Peat, an unconsolidated accumulation of

partly decomposed plant material, has an

approxi-mate carbon content of 20 percent In many

classifica-tion schemes, peat is listed as the initial stage of coal

formation Moisture content is quite high, at least at

the 75 percent level When dry, peat has an oxygen

content of about 30 percent, is flammable, and will

freely but inefficiently burn slowly and steadily for months at a low-heat-content value of 5,400 British thermal units (Btus) per pound

Lignite Lignite, or brown coal, is brownish-black

in color, banded and jointed, and subject to spontane-ous combustion Carbon content ranges from 25 to 35 percent With a moisture content around 40 percent,

it will readily disintegrate after drying in the open air Because lignite has a maximum calorific value of 8,300 Btus, it is classed as a low-heating-value coal Bituminous coal Deeper burial with even higher temperatures and pressures gradually transforms lig-nite into bituminous coal, a dense, dusty, brittle, well-jointed, dark brown to black fuel that burns readily with a smoky yellow flame Calorific value ranges from 10,500 to 15,500 Btus per pound, and carbon content varies from 45 to 86 percent Moisture content is as low as 5 percent, but heating value is high

Subbituminous Coal The subbituminous class of coal is intermediate between lignite and bituminous and has characteristics of both Little woody matter is visible It splits parallel to bedding but generally lacks the jointing of bituminous coal It burns clean but with a relatively low heating value

Anthracite Anthracite is jet black in color, has a high luster, is very hard and dust free, and breaks with a conchoidal fracture Carbon content ranges from 86 to

98 percent It is slow to ignite; burns with a short blue flame without smoke; and, with a calorific value in ex-cess of 14,000 Btus per pound, is a high heating fuel

Description, Distribution, and Forms Coal is a fossil fuel found on all seven continents and is

in commercial production on all but the continent of Antarctica The top-ten producers of coal in 2008 were China, the United States, Australia, India, South Africa, Russia, Indonesia, Poland, Kazakhstan, and Colombia In 1992, a reserve of more than 185 billion metric tons of lignite was discovered in Pakistan, but the cost of production and lack of infrastructure have prevented development or accurate analysis of the field

The quantitative distribution of coal is more diffi-cult to determine than its geographic distribution Es-timates indicate that total world coal resources, de-fined as coal reserves and other deposits that are not economically recoverable plus inferred future discov-eries, are on the order of 9 trillion metric tons and ex-ist in every country Of this amount, estimates of world coal reserves, defined as those deposits that

have been measured, evaluated, and can be extracted

profitably under existing technologic and economic

conditions, are approximately 900 billion metric tons

and are found in about seventy countries If the latter

figure is accepted as reasonable, world reserves can be

divided into two categories, with about three-quarters

composed of anthracite and bituminous coals and

about one-quarter composed of lignite When the

lig-nite reserves in Pakistan can be reliably analyzed,

these figures will change

On a country-to-country comparison, the United

States possesses the greatest amount of total world

coal reserves Geographic distribution in the United

States is divided into five coal provinces, incorporat-ing at least thirty-three states These are termed the Appalachian or Eastern, the Interior, the Gulf, the Rocky Mountain, and the Northern Great Plains coal provinces

The Eastern (Appalachian) province, stretching along the flanks of the Appalachian Mountains from northern Pennsylvania into central Georgia, contains approximately 40 percent of the bituminous coal serves of the United States as well as the principal re-serve of anthracite rank coal on the continent Within the Interior province, bituminous coals are divided among the Michigan, Illinois, and Western Interior

Source: Statistical Review of Energy, 2009

152,800,000 141,100,000 141,100,000 60,500,000 58,800,000 47,800,000 47,700,000 40,200,000 36,000,000

Metric Tons

1,500,000,000 1,250,000,000

1,000,000,000 750,000,000

500,000,000 250,000,000

Ukraine

Kazakhstan

Poland

South Africa

Indonesia

Russia

Colombia

Germany

Canada

India

Australia

United States

China

194,300,000 219,900,000

596,900,000

1,414,500,000 Coal: Top World Producers, 2008

basins, the latter located in Iowa, Missouri, Kansas,

and Oklahoma Lignite is the chief coal found in the

Gulf province, situated in Mississippi, northern

Loui-siana, and coastal Texas Rocky Mountain bituminous

and subbituminous deposits are scattered throughout

at least five states from Wyoming south into Arizona

and New Mexico Lignite and bituminous coals

con-stitute the Northern Great Plains province of

Mon-tana and portions of North and South Dakota

Coal is mined in twenty-five states, but ten states

alone contain 90 percent of the total U.S reserves

These are, in order of increasing reserve tonnage,

In-diana, Texas, Colorado, Ohio, Kentucky,

Pennsylva-nia, West VirgiPennsylva-nia, Wyoming, Illinois, and Montana

Montana contains a full 25 percent of U.S coal

re-serves

Small reserves of relatively low-grade coal are

known in the Pacific Northwest region Significant

amounts of coal have been discovered in Alaska, but

difficulty in mining and great distance to markets cause these deposits to be classed as resources and not economic reserves

Following the United States, the countries with the largest coal reserves are Russia, China, India, Austra-lia, and South Africa Estimates indicate that global coal reserves will last some 130 to 150 years at current production levels, although by some methods of cal-culation that period is significantly shorter

The more common and ordinary coals are of vas-cular vegetable origin, formed from the compaction and induration of accumulated remains of plants that once grew in extensive swamp and coastal marsh ar-eas These deposits are classed as humic coals consist-ing of organic matter that has passed through the peat, or earliest coal formation, stage A variety of humic coals are known

The swamp-water environment in which humic coals form must be deficient in dissolved oxygen, the

Data from U.S Mining Association (converted from short tons).

Source:

29.4 31.7

104.6

39.4 26.8

59

38

139

411

Million Metric Tons

500 400

300 200

100 West Virginia

North Dakota

Montana

Kentucky

Indiana

Illinois

Pennsylvania

Texas

Wyoming

Leading U.S Coal-Producing States, 2007