Encyclopedia of Global Resources part 24 ppt

cubic meters, or almost equal to China’s total annual
runoff.
In addition to fisheries and transportation, irriga-
tion, hydration, industrial, and numerous other uses,
water resources in China are a significant energy re-
serve. The total hydrological power reserve is esti-
mated at 680 million kilowatts, ranking first in the
world. Of thetotal, 380 million kilowatts can be devel-
oped to generate1.9trillion kilowatt-hours of electric-
ity, whichcontribute a great deal to China’s economic
development and the world economy.
Climate Resources
China’s vast territory spans multiple climate zones
from the south to the north, including tropical, sub-
tropical, warm temperate, temperate, and boreal. In
addition, the Qinghai-Tibet Plateau has a unique al-
pine region. Nevertheless, the subtropical, warm tem-
perate, and temperate climate zones compose ap-
proximately 70 percent of the country. As diverse as
the climate is, the basic characteristic is a continental
monsoon climate, whichexhibits three mainfeatures:
substantial daily and seasonal temperature differen-
tial; uneven precipitation distribution, with a steady
drop from the southeast to the northwest by a dra-
matic 40:1ratio; and dramatic wind turnover between
winter and summer. During the winter, cold and dry
air from high latitude rises from the north. In sum-
mer, warm and humid wind comes mainly from the
ocean in the southeast.
The average annualtemperatures in theeastern re-
gion descendfrom south to north, from 25° Celsiusto

5.5° Celsius. Most of thewestern Qinghai-Tibet Plateau
has annual average temperatures below 0° Celsius, but
the Tarim basinis10°Celsius. The temperature differ-
ential in the summer between the south and north is
small, only 10° Celsius. In the winter, however,the tem-
perature difference between these two regions can be
as much as 50° Celsius. The lowest temperature in the
Mohe area can dip below −50° Celsius. The average
annual precipitation across China is 629 millimeters,
with a steady decline in annual precipitation from
southeast to northwest, which is somewhat similar to
the annual temperature patterns. In general, high
precipitation is concentrated in the summer months.
Based on the annual rainfall pattern, China’s areas
can be divided into 32 percent subhumid, 18 percent
semihumid, 19 percent semiarid,and31percentarid.
The temperature and annual precipitation pattern
results in aconcentrated distribution ofagriculture in
central and southeast provinces and the Sichuan ba
-
sin, areas that are thefoundation of China’s economy.
The vast territory in the northwest is not productive
and contributes little to China’s agriculture.
Biological Resources
China is blessed with rich biological resources. It has
more wild animal species than any other country. Ver-
tebrates alone accountfor5,200 species, 11 percent of
the world’s total. Of these animals, 499 species are
mammals, 1,186 are birds, 376 are reptiles, 279 are
amphibians, and 2,804 are fish. This wildlife consists

of many endemic species, including some of the most
well-known and rare animals: the giant panda,
golden-haired monkey, Chinese alligator, crested ibis,
white-lipped deer, South China tiger, red-crowned
crane, brown-eared pheasant, and Yangtze River dol-
phin (though this animal is thought to be extinct).
The diverse flora in China includes twenty-five
thousand species of seed plants. From the tropical
rain forests to the boreal coniferous forests, Chinahas
almost all the natural vegetation characteristic of the
Northern Hemisphere. The two hundred or so spe-
cies of gymnosperms account for 25 percent of the
world’s total. In addition, there are seven thousand
species of woody plants andtwenty-nine hundred spe-
cies of trees. Severalendemic plant speciesare consid-
ered as “living fossils,” including ginkgo, metasequoia,
and golden pine.
China has more thanfivethousand years ofagricul-
tural history, during which time the country has con-
tributed many major crops important to humankind,
including rice, soybeans, peaches, pears, plums, dates,
grapefruit, lychees, and tea. Based on their utiliza-
tion, China has one thousand plant species for timber
wood, three hundred starchy plants,more than ninety
vegetable species, and six hundred oil species. Its
crops and germplasm continue to make vital contri-
butions to the world’s economy.
Mineral Resources
China possesses deposits of all the discovered miner-
als. China’s total reserve of 146 mineral resources

ranks the country third among world nations. Coal,
with a proved reserve of 877 billion metric tons, is
found mainly in northern China, including the prov-
inces of Shaanxi, Liaoning, Nei Monggol, and Hei-
longjiang. Among the 250 or so petroliferous basins
identified, more than half of them (130) are under
development.
200 • China Global Resources
The identified iron-ore reserves are estimatedat 41
billion metric tons and distributed in multiple re-
gions. China also ranks among leading nations in re-
serves of minerals such as tungsten, tin, antimony,
zinc, molybdenum, lead, and mercury. China’s rare
earth reserves are more than the rest ofthe world’s to-
tal combined. In fact, China accounts for 80 percent
of the world’s total reserves in that category. The
diverse minerals and their large reserves provide im-
portant raw materials and energy sources that will
continue to power China’s economic growth and de-
velopment.
In 1996, China established a thorough (although
not perfect) legal system for the exploration and ex-
ploitation ofits minerals.This system consists of many
laws, regulations, and rules promulgated by different
levels of government authorities. Ononehand,China
has encouraged foreign investment in mineral re-
sources exploration and new mining technologies.
On the other hand, China imports minerals from
other countries and invests heavily in acquiring min-
eral resources abroad. In 2008, China bought more

than half of Australia’s mineral exports. China has be-
come the world’s largest consumer of raw materials.
Energy Resources
China is rich in energy resources, but their distribu-
tion is uneven. China ranks third among world na-
tions in energy reserves and output, with a total en-
ergy production equivalent to 11 billion metric tons
of standard coal. In 2007, China’s coal output was 2.3
billion metric tons, which was top among countries;
its crude oil output was 172 million metric tons,
which ranked fifth; and its power generation capacity
was 720 gigawatts, which was fourth. Gas production
reached 76 billion cubic meters in 2007.
China relies heavily on coal for energy, but 80 per-
cent of the coal reserves are concentrated in the
north. The most economically developed eight prov-
inces south of the Chang River account for only 2 per-
cent ofthe total coal reserves. About85 percent ofthe
proved oil reserves are concentrated in the east re-
gion, north of the Chang. Sixty-eight percent of hy-
draulic power developed is in the southwest region.
China has addressed the low energy reserves in the
economically vibrant south through the construction
of nuclear power plants.
The rapid economic growth anddevelopment that
began in 1982 have created an insatiable demand for
fossil fuel (oil and gas) that far exceeds China’s own
production capacity. Thus, China became a major im
-
porter of oil beginning in the early 1990’s. China im-

ported 162 million metric tons of crude oil in 2007. A
limit to China’s storagecapacityis the onlyreasonthat
figure is not higher. That limit will soon change as
China builds more strategic oil reserve facilities in
the western region. In short, China has become the
world’s second largest energy user, trailing only the
United States. With an ever-increasing demand for
oil, China is a driving force for energy consumption.
This in turnwill have asignificantimpact on theworld
economy and environment.
Other Resources
China is a country rich in tourism resources. Its vast
territory and complex topography provide visitors to
China with year-round opportunities. The natural
scenery in thenorth presents thousands ofkilometers
of glaciers and snowy land during the winter. The
southern regions provide tourists with lush scenes of
vegetation. China’s exotic flora and fauna, found in
its many nationalnature reserves, attracttourists of all
ages. China is dotted with magnificent rivers, lakes,
mountains, and canyons. Its long cultural history has
produced numerous world-class attractions. In addi-
tion, the relatively low cost of travel and lodging, com-
bined with the world’s burgeoning desire to know
China, has fueled the powerful tourism engine in
China.
As one of the world’s four ancient civilizations,
China is full of historical sites and cultural relics.
Some of the most famous attractions include the
Great Wall, the Terracotta Army, Ming Tombs, Peking

Man, and many other attractions of historicaland cul-
tural significance.
Ming Y. Zheng
Further Reading
Forney, Matthew. “China’s Quest for Oil.” Time (Octo-
ber 18, 2004).
Lew, Alan A., and Lawrence Yu. Tourism in China: Geo-
graphic, Political, and Economic Perspectives. Boulder,
Colo.: Westview Press, 1995.
National Geographic Society. NationalGeographicAtlas
of China. Washington, D.C.: Author, 2007.
Sheehan, Peter. Implications of China’s Rising Energy
Use. Singapore: World Scientific, 2008.
Xie, Jian, et al. Addressing China’s Water Scarcity: Recom
-
mendations for Selected Water Resource Management Is
-
sues. Washington, D.C.: World Bank, 2009.
Global Resources China • 201
Zhang, Q., et al. “Precipitation, Temperature, and
Runoff Analysis from 1950 to 2002 in the Yangtze
Basin, China.” Hydrological Sciences Journal 50, no. 1
(2005): 65-80.
Web Site
CIA World Factbook
/>world-factbook/
See also: Agricultural products; Agriculture indus-
try; Ecozones and biogeographic realms; Energy poli-
tics; Hydrogen; Population growth; Three Gorges
Dam.

Chlorites
Category: Mineral and other nonliving resources
Chlorites are mostcommonlyfound as microscopic par-
ticles in clays. They are also found in metamorphic
rocks such as schists. Metamorphic chlorites are com-
monly found in Michigan, Norway, the United King-
dom, and Japan. Chlorites also occur in igneous rocks
as a productof biopyriboles thathave been transformed
by heat and moisture. They may also be found in sedi-
mentary rocks formed from pieces of older igneous or
metamorphic rocks containing chlorites.
Definition
The term “chlorite”(from theGreekword for “green”)
refers to a variety of hydrous aluminum silicates of
magnesium, iron, and other metals. They are soft
green minerals with a glassy luster. Chlorites are brit-
tle and can be ground into white or pale green pow-
der easily. Thin sheets of chlorite are flexible but not
elastic.
Chlorites are agroup of silicateminerals consisting
of alternating layers of molecules forming two kinds
of two-dimensional sheets. One layer consists of sili-
cate groups (one silicon atom bonded to four oxygen
atoms) bound to aluminum atoms, hydroxyl groups
(one oxygen atom bonded to one hydrogen atom),
and magnesium, iron, or other metallic atoms. The
other layer consists of magnesium, iron, aluminum,
or other metallic atoms bound to hydroxyl groups. If
most of the metallic atoms other than aluminum are
magnesium, the mineral is known as clinochlore. If

the metallic atoms are iron, it is known as chamosite.
If they are nickel, it is known as nimite. If they are
manganese, it is known as pennantite. These four
minerals are very similar.
Overview
Chlorites are most useful in the form of clay minerals.
They mix with other substances to form clays that are
widely used in pottery and construction. Clay miner-
als are also used in drilling “muds” (thick suspensions
used to lubricate rotary drills). They may also be used
as catalysts in petroleum refining and to decolorize
vegetable oils.
The density of chloriterangesfrom2.6to 3.3 grams
per cubic centimeter. On the Mohs scale, they have a
hardness between 2 and 2.5; they are generally soft
enough to be scratched with a fingernail.
Chlorite usuallyexists as amicroscopic component
of clay, along with organic material, quartz, and other
minerals. Visible pieces of chlorite may be found
within a variety of rocks, particularly metamorphic
rocks such as the very common schists.
Chlorites are chemically similar to other clay min-
erals (hydrous aluminum silicates) and are often
found in combination with them. They are generally
more resistant to heat than other clay minerals are.
This fact is used to detect chlorite within clays. A sam-
ple of the clay is heated to between 500° and 700° Cel-
sius, whichbreaks downthe otherclay minerals. X-ray
diffraction is then used to detect the layers of silicate
chains that are characteristic of clay minerals. If this

pattern is detected, chlorite is present in the sample.
In other regards chlorites have about the same prop-
erties as other clay minerals.
Rose Secrest
See also: Aluminum; Clays; Metamorphic processes,
rocks, and mineral deposits; Silicates.
Chromium
Category: Mineral and other nonliving resources
Where Found
Chromium is a moderately abundant element that
does not occur free in nature. Its principal ore is
known as chromite, (Fe,Mg) (Cr,Al)
2
O
4
. The world’s
chromite resources are concentrated in the Eastern
202 • Chlorites Global Resources
Hemisphere, with major producers including South
Africa, Kazakhstan, India, Zimbabwe, Turkey, Fin-
land, and Brazil.
Primary Uses
Chromium is a strategic and critical resource used
principally in the production of alloys and superal-
loys, stainless steel, refractory materials, pigments,
and chemicals. It is used for dyeing textiles and leather
tanning and as a laboratory glassware cleanser. Fur-
thermore, chromium in its trivalent oxidation state is
an essential trace nutrient for humans and other
mammals.

Technical Definition
Chromium (abbreviated Cr), atomic number 24, is a
metallic chemical elementbelonging to Group VIBof
the periodic table of the elements. It has four natu-
rally occurring isotopes and an average molecular
weight of51.996. Pure chromium is silver-gray, brittle,
and hard. Its specific gravity is 7.19 at 20° Celsius, its
melting point is approximately 1,890° Celsius, and its
boiling pointis 2,200° Celsius. This lustrous metal will
take a highpolishand does nottarnish inair.In chem-
ical compounds chromium may have oxidation states
ranging from −2to +6,but inmost compounds it is tri
-
valent (+3) or hexavalent (+6). The trivalent state is
more common in naturally occurring compounds,
while hexavalent chromium is frequently found in in-
dustrial applications.
Description, Distribution, and Forms
Chromium is a commercially important metallic ele-
ment. Forming compounds with brilliant red, yellow,
and green hues, it derives its name from the Greek
chroma (color). Its concentration in the lithosphere is
100 grams per metric ton. Total world production of
chromite is about 20 million metric tons. Trivalent
chromium, the form most often found in nature, is a
trace element inthehuman body; bycontrast,hexava-
lent chromium is a highly toxic substance whose con-
centrations in the environment are regulated by law.
Approximately 95 percent of the world’s chro-
mium resources are found in southern Africa, with

South Africa the leading producer in the region.
Other world producers include Kazakhstan, India,
Turkey, Finland, Brazil, and Russia. Chromium is
present in a number of minerals, but chromite is its
only commercial ore. Primary deposits of chromite
occur as stratiform and podiform ores found in cer-
tain types of ultrabasic (low-silica) rocks. Secondary
alluvial deposits of chromite are formed by the weath-
ering of stratiform (layered) and podiform ores.
Stratiform chromite deposits are often several me
-
ters thick, extend over large areas, havea relatively uni
-
form composition, and frequently include platinum-
Global Resources Chromium • 203
Data from the U.S. Geological Survey, . U.S. Government Printing Office, 2009.Source: Mineral Commodity Summaries, 2009
3,300,000
3,700,000
9,600,000
Withheld
4,900,000
Metric Tons Gross Weight
10,500,0009,000,0007,500,0006,000,0004,500,0003,000,0001,500,000
United States
India
Kazkhstan
South Africa
Other countries
U.S. data were withheld to avoid disclosure of company propriety data.Note:
Chromium: World Mine Production, 2008

bearing zones. They formed as chromite crystallized
and precipitated from silicate melts. Examples in-
clude the Bushveld Igneous Complex in Transvaal,
South Africa; the Great Dyke in Zimbabwe; and the
Stillwater Complex in Montana. Stratiform deposits
constitute more than 90 percent of the world’s identi-
fied chromite reserves. All the commercially signifi-
cant stratiform chromites are Precambrian in age and
occur in stable cratons, portions of the Earth’s crust
that have experienced little deformation over a long
period of geologic time.
In podiform deposits, chromite occurs as irregular
pods or lenses within the host rock. Major podiform
deposits are found in Kazakhstan, Albania, Greece,
Turkey, Zimbabwe, Cuba, and the Philippines. Po-
diform chromites form along island arcs and mobile
mountain belts, and most are of Paleozoic age or
younger.
Chromium occurs in nature only in combination
with other elements. The most important chromium
ore is chromite, a brownish-black to iron-black min-
eral of the spinel group. It occurs as octahedral crys-
tals, irregular masses, and alluvial deposits. Other
minerals that contain chromium include the gem-
stones emerald and aquamarine, which owe their dis-
tinctive colors to the element.
Chromium plays a role in the body’s glucose toler-
ance. Moderate amountsoftrivalent chromium inthe
diet have no apparent harmful effects. Chromium
metal is biologically inert and has no known toxicity.

While trivalent chromium compounds exhibit lit-
tle or no toxicity, hexavalent chromium is a systemic
poison and an irritant and corrosive. It can be ab-
sorbed by ingestion, inhalation, or dermal exposure.
Ulcerations of the skin and mucous membranes may
result from exposure. Chromate salts are suspected
human carcinogens that may produce tumors of the
lungs, nasal cavity, and paranasal sinuses. The 1974
Safe Drinking Water Act set the maximum allowable
concentration for total chromium in drinking water
in the United States at 100 micrograms per liter.
In general, chromium does not naturally occur in
high concentrations in water. Elevated chromium lev-
els in surface water or groundwater are typical be-
cause of contamination from runoff from old mining
operations or improper disposal of electroplating
wastes. However, in the groundwater of Paradise Val-
ley in Maricopa County, Arizona, hexavalent chro
-
mium of natural origin is present in concentrations
exceeding 200 micrograms per liter. The alkaline
groundwater causes naturally occurring trivalent chro
-
mium in thesoil to oxidizeto soluble hexavalentchro-
mium.
History
Chromium appears to have been unknown to ancient
civilizations. It was discovered in 1797 by Louis-
Nicolas Vauquelin, a French chemist, when he found
that the leadinasample of crocoite (PbCrO

4
)fromSi-
beria was combined with an unknown oxide mineral.
Between the time of chromium’s discovery and 1827,
the primary source of chromite was the Ural Moun-
tains of Russia. In 1827, the discovery of chromite in
Maryland moved the United States to the forefront of
world production. Large Turkish deposits were devel-
oped in the 1860’s; after this time, the Eastern Hemi-
sphere became the chief source of chromite. The
chemical manufacturing industry was the main con-
sumer of chromium until the early 1900’s, when the
element found increasing use in metallurgical andre-
fractory products. During World Wars I and II, the
United States increased its domestic production of
the metal, and during the 1950’s it stockpiled domes-
tic ores. International political conflicts have often
led to interruptions in chromium supply.
Obtaining Chromium
Sodium dichromate, from which most commercial
chromium compounds are made, is produced by
roasting chromite with sodium carbonate, leaching
the resulting product with water, and concentrating
and acidifying the leachate to cause sodium dichro-
mate to precipitate. Ferrochromiumis prepared from
chromite by reducing the ore with carbon in a blast
furnace. Metallic chromium is obtained by reducing
chromium oxide with aluminum or carbon, or by
electrolyzing a solution of ferrochromium dissolved
in sulfuric acid after the iron has been removed from

the solution as ferrous ammonium sulfate. Chromium
metal in its purest form is produced in small quanti-
ties by vapor deposition from anhydrous chromium
iodide.
Uses of Chromium
The principal use of chromium is as an alloy metal,
particularly in the steel industry. Combined with other
metals, it imparts hardness, strength, and resistance
to corrosion andheat. Chromium facilitates the hard
-
ening of steel and, if the alloy’s carbon content is
high, enables it to withstand extreme abrasion and
204 • Chromium Global Resources
wear. In ball-bearing steel, chromium improves the
elastic limit and imparts an evenly distributed hard-
ness. Chromium increases the corrosion resistance of
stainless steel and is an important alloy metal in heat-
resisting steels. High-chromium steel, with its high re-
sistance to wear, is used for making items such as die
blocks, press plates, chisels, hacksaw blades, and cir-
cular steel saws. Nichrome, an alloy of nickel and
chromium, is used as a heating element in household
appliances such as electric toasters and coffeepots.
Stellite, an extremely hard alloy of cobalt, chromium,
and tungsten with minor amounts of iron, silicon,
and carbon, is used in metal cutting tools and wear-
resistant surfaces. A similar alloy, which employs mo-
lybdenum rather than tungsten, is used in surgical
tools. With its hardness and nontarnishing proper-
ties, chromium is also an ideal electroplating metal.

Chromium’s uses in alloys and plating make it an im-
portant strategic and critical metal.
Chromite is a valuable raw material for the manu-
facture of refractory materials such as refractory
bricks, foundry sand, and casting items for furnaces
used in metallurgy. Refractory materials are able to
withstand high temperatures and contact with often
corrosive gases and molten materials. Chromite is fre-
quently used in combination with other refractory
materials; for instance, mixed with the magnesium
ore magnesite (magnesium carbonate) and fused in
an arc furnace it is cast into refractory brick.
Various chromates and dichromates, salts of chro-
mic acid, are used as pigments in paints and dyes,
yielding vivid yellows, reds, oranges, and greens.
Chromium hydroxide is used as a mordant in textile
dyeing. Potassium dichromate mixed with sulfuric
acid is used as a cleanser for laboratory glassware.
Chromium compounds are also used in chemical
manufacture and leather tanning.
Karen N. Kähler
Further Reading
Adriano, Domy C. “Chromium.” In Trace Elements in
Terrestrial Environments:Biogeochemistry, Bioavailabil-
ity, and Risks of Metals. 2d ed. New York: Springer,
2001.
Greenwood, N. N., and A. Earnshaw. “Chromium,
Molybdenum, and Tungsten.” In Chemistry of the El-
ements. 2d ed. Boston: Butterworth-Heinemann,
1997.

Guertin, Jacques, et al., eds. Chromium (VI) Handbook.
Boca Raton, Fla.: CRC Press, 2005.
Independent Environmental Technical Evaluation
Group. Chromium (VI) Handbook. Edited by Jacques
Guertin, James A. Jacobs, and Cynthia P. Avakian.
Boca Raton, Fla.: CRC Press, 2005.
Katz, Sidney A., and Harry Salem. The Biological and
Environmental Chemistry of Chromium. New York:
VCH, 1994.
Kogel, Jessica Elzea, et al., eds. “Chromite.” In Indus-
trial Minerals and Rocks: Commodities, Markets, and
Uses. 7th ed. Littleton, Colo.: Society for Mining,
Metallurgy, and Exploration, 2006.
Manning, D. A. C. Introduction to Industrial Minerals.
New York: Chapman & Hall, 1995.
Nriagu, Jerome O., and Evert Nieboer, eds. Chromium
in the Natural and Human Environments. New York:
Wiley, 1988.
Udy, Marvin J. Chemistry of Chromium and Its Com-
pounds.Vol1ofChromium. New York: Reinhold,
1956.
Web Sites
Natural Resources Canada
Canadian Minerals Yearbook, Mineral and Metal
Commodity Reviews
/>indu/cmy-amc/com-eng.htm
U.S. Geological Survey
Chromium: Statistics and Information
/>commodity/chromium
See also: Alloys;Brazil;India;Kazakhstan; Metals and

metallurgy; Plutonic rocks and mineral deposits; Rus-
sia; South Africa; Steel; Strategic resources; Turkey;
United States.
Civilian Conservation Corps
Category: Organizations, agencies, and programs
Date: Established 1933
The Civilian Conservation Corps, a central part of
Franklin D. Roosevelt’s “New Deal,” was conceived as
a comprehensive project which would encompass relief
for the unemployed, recovery of the nation’s economic
health, and conservation of American natural re
-
sources.
Global Resources Civilian Conservation Corps • 205
Background
In 1934, President Franklin D. Roose-
velt noted that the United States was
one of the few industrialized countries
that had notestablisheda “national pol-
icy forthe development ofour land and
water resources.” This lack was in the
process of rectification when, inMarch,
1933, shortly after his inauguration,
Roosevelt proposed the establishment
of the Civilian Conservation Corps
(CCC). The legislationprovided forthe
voluntary mobilization of unemployed
young men to work on various conser-
vation projects throughout the nation.
As Congress did on most of Roose-

velt’s proposals during his first one hun-
dred days in office, it acted swiftly, ap-
proving the legislation on March 31,
1933. Administered by the Labor De-
partment, the Army, the Forestry Ser-
vice, and the National Park Service, the
CCC had the potential to be an administrative disas-
ter, but disaster did not happen. By July more than
300,000 unemployed young men, aged eighteen to
twenty-five and from families on relief, were already
working in the CCC’s thirteen hundred camps. By
1935, there were more than 500,000 men in the CCC,
and before it was dismantled more than 2.5 million
young men hadjoined,workingfor one dollar adayin
twenty-five hundred camps.
Impact on Resource Use
The projects were varied, ranging from restoring bat-
tlefields of the American Revolution and Civil War to
constructing trails intheHigh Sierra; from protecting
wildlife (including stocking almost one billion fish)
and building fire lookout towers to planting two bil-
lion trees—200 million as windbreaks in the Dust
Bowl. Estimates indicate that of all the forests planted
in the history of the United States, both public and
private, more than half were planted by the so-called
tree peopleof theCCC. From the east and west, north
and south, farm boys worked alongside young men
from the cities. The CCC was organized on a military
basis, although participation was voluntary, and one
could enter and leave when one wished. Most men

stayed from several months to about one year.
Although women were excluded and African Amer
-
icans were subject to a 10 percent quota and were usu
-
ally segregated, as a conservation organization, the
CCC was aninstant and lastingsuccess.Many of Amer-
ica’s natural resources were preserved during those
few years of the 1930’s in spite of the predictions by
some that many of the projects were beyond the gov-
ernment’s powers andthattheCCC would be inimical
to capitalism or to organized labor because of the
CCC’s low wages. Some feared that the CCC smacked
of communist collectivism or fascist militarism. Not
the least of the resources conserved were the young
men themselves, whose experience developed their
physical bodies as well as their intellectual and emo-
tional capabilities. At the onset of World War II the
CCC was terminated, but individual states later estab-
lished their own conservation corps, such as the Cali-
fornia Conservation Corps. John F. Kennedy’s Peace
Corps was also inspired in part by the CCC.
Eugene Larson
Web Sites
Civilian Conservation Corps
Civilian Conservation Corps Legacy
/>National Archives
Records of the Civilian Conservation Corps
/>records/groups/035.html#35.4
206 • Civilian Conservation Corps Global Resources

Members of the African American Civilian Conservation Corps reconstruct gabions
at the French Battery along York-Hampton Road in Yorktown, Virginia, in the mid-
1930’s. (National Park Service Historic Photograph Collection)
See also: Conservation; Dust Bowl; Forest Service,
U.S.; Reforestation; Roosevelt, Franklin D.
Clays
Category: Mineral and other nonliving resources
The term “clay” may be used to describe a groupof fine-
grained minerals, a type of rock, or a range of particle
size, generally less than four micrometers. As a rock
term, clay is generally understood to mean an earthy,
fine-grained material formed largely of crystalline
minerals known as the clay minerals.
Background
Clays can be found throughout the world, but eco-
nomically valuable deposits are limited in extent and
distribution. Majorkaolin deposits inthe UnitedStates
are found in Georgia and SouthCarolina.The
world’s major bentonite deposits are found
in Wyoming and Montana, and large fuller’s
earth deposits can be found in Georgia and
Florida. Ball and refractory clays are abun-
dant in Kentucky and Tennessee.
Clays are used in a number of applications
requiring the incorporation of fine-grained
materials that contribute to a product’s physi-
cal or chemicalproperties. Usesincludefillers
in paint, paper, and plastics, additives to drill-
ing muds, the manufacture of ceramics and
brick, carriers for pesticides and insecticides,

the manufacture of catalysts, and cosmetic
and pharmaceutical uses.
Clays are considered “industrial minerals,”
a group of minerals composed of geological
materials having commercial value and of a
nonmetallic, nonfuel character. They may be
marketed in a natural, as-mined state or as
processed materials. Clays can vary widely in
composition andphysical characteristics.Cer-
tain similarities exist among a number of clays,
however,and they canbecategorized in broad
terms as kaolin, bentonite or fuller’s earth,
ball clay, and refractory clay based on similari-
ties in either composition or functional per-
formance. Clays that donot fall intoany of the
major categories are generally referred to as
common clay or shale.
Mineralogy and Chemistry
Clays are hydrous (water-containing) aluminum sili-
cates containing alkalies or alkaline earth elements.
Magnesium or iron may substitute wholly or partially
for aluminum in the clay mineral structure. Clay min-
erals are composed of alternating layers of two differ-
ent atomic structures. The first is an aluminum-bear-
ing octahedral sheet structure, and the second is a
layer of silica tetrahedrons. The aluminum and sili-
con atoms are chemically bonded to oxygen in these
layers, which are held to one another by weaker elec-
trostatic bonds. Interlayer sites in many clays contain
water molecules or cations such as calcium, sodium,

potassium, magnesium, lithium, or hydrogen. The
presence or absence of interlayer molecules affects
both the physical andchemicalpropertiesof the clay.
Kaolin
Kaolin is a clay consisting predominantly of pure
kaolinite or related clay minerals. Most major depos-
Global Resources Clays • 207
Bricks and
concrete block
65%
Structural
concrete
3.5%
Portland &
other cements
19%
Ceramics,
glass, & tile
3%
Other
9.5%
Source:
Historical Statistics for Mineral and
Material Commodities in the United States
Note:
U.S. Geological Survey, 2005, clay and shale statistics, in T. D.
KellyandG.R.Matos,comps.,
,U.S.GeologicalSurvey
Data Series 140. Available online at />2005/140/.
“Other” includes ceramics and glass, floor and wall tile,

highway surfacing, other lightweight aggregates, refractories,
and other heavy clay products.
U.S. End Uses of Clay and Shale
its of kaolin are referred to as either primary (resid
-
ual) or secondary. Primary deposits are formed in
place as the weathering products of granite or other
feldspar-rich rocks. Other minerals associated with
deposits of this type include quartz, micas, amphi-
boles, tourmaline, and unweathered feldspars. Pri-
mary deposits are irregular in shape, grading down-
ward into unaltered parent (source) rock.
Secondary deposits of kaolin are sedimentary ac-
cumulations of kaoliniticmaterial thathas been trans-
ported from its source area. Deposits of this type may
contain up to 95 percent kaolinite; in contrast, pri-
mary deposits maycontain as littleas10 percent. Asso-
ciated minerals may include quartz, micas, other clay
minerals, and a variety of high-density “heavy miner-
als.” Secondary deposits are generally lenticular or
tabular in shape, with thicknesses up to sixty meters
and areal dimensions of up to about two kilometers.
Kaolin isalso found asa product ofhydrothermally
altered rocks. Deposits of this nature are of limited
size and extent. They occur as irregularly elongated
pods or pipelike bodies along faults, joints, and other
conduits along which hot solutions have flowed.
Kaolin is generally soft and plastic, although harder
silica-bearing varieties also exist. Crystals of kaolinite
are hexagonal, composed of individual platelets

stacked in an accordion-like manner. There is little
ionic substitution in the crystal lattice.
Kaolin has numerous industrial usesandis perhaps
best known foritsuse in themanufactureof china and
porcelain. Its chemical inertness, high brightness,
white color (either naturally or resulting from pro-
cessing and beneficiation), and crystal shape make it
useful in other applications as well. Kaolin is used as a
filler or coating in themanufacture of paper, asa filler
in paint, plastics, and pharmaceuticals, and in the
manufacture of rubber, tile, brick, ink, adhesives, de-
tergents, cosmetics, pencils, pastes, and other con-
sumer products.
Ball Clay and Refractory Clay
Ball clays are composed of up to 70 percent kaolin.
They generally occur in secondary sedimentary de-
posits characterized by thepresence oforganicmatter
along with varying amounts of other clays, quartz,
feldspar, calcite, and heavy minerals.Sedimentary de-
posits of ball clay represent accumulations of clay ma-
terials that were derived from a number of sources
and that were deposited in nonmarine environments.
Most deposits are lenticular, with areal dimensions of
up to 850 meters and thicknesses of up to 10 or more
meters.
208 • Clays Global Resources
Clay and Shale: World Mine Production, 2008
Metric Tons
Nation Bentonite Fuller’s Earth Kaolin
Brazil (beneficiated) 240,000 — 2,490,000

Commonwealth of Independent
States (crude) 750,000 — 6,200,000
Czech Republic (crude) 220,000 — 3,800,000
Germany (sales) 385,000 — 3,850,000
Greece (crude) 950,000 — 60,000
Italy (kaolinitic earth) 600,000 3,000 580,000
Mexico 435,000 100,000 960,000
South Korea (crude) — — 2,600,000
Spain 105,000 870,000 450,000
Turkey 930,000 — 580,000
United Kingdom — — 1,750,000
United States (sales) 4,870,000 2,630,000 6,750,000
Other countries 2,520,000 297,000 8,630,000
Source: Data from the U.S. Geological Survey, Mineral Commodity Summaries, 2009. U.S. Government Printing Office, 2009.
Ball clays are plastic or semi-plastic and are used to
provide strength and malleability to ceramic bodies
prior tofiring. They fuse during firing, also acting as a
“cement” to bind together the refractory, nonshrink-
ing component of a ceramic body. Ball clay is used to
manufacture tableware, stoneware, tiles, plumbing
fixtures, and bricks. It is also used as a sealant in land-
fills.
Refractory clays are generally kaolin, containing
only small quantities of micaor iron-bearing minerals
that might combinewithother materials duringfiring
to form low-melting-point glasses. Refractory clays
have a high heat resistance. Other properties that af-
fect overall quality include shrinkage, warping, crack-
ing, and abrasion. Refractory clays can be soft and
plastic or hard like flint. They generally occur as sedi-

mentary deposits that are lenticular or tabular in
shape. They are mined for use in the manufacture of
firebrick, insulating brick, and other heat-resistant
clay products.
Bentonite and Fuller’s Earth
“Bentonite” is generally understood to mean a clay
consisting of minerals from the montmorillonite
group, regardless of origin or occurrence. The most
important commercial montmorillonites are the so-
dium and calcium varieties. Sodium montmorillonite
(Wyoming or western bentonite) hashigh swelling ca-
pabilities when addedto water. Calciummontmorillo-
nite (southern bentonite) has a lower swelling capac-
ity, and it generally crumbles when added to water.
Other montmorillonites include those rich in lithium
(hectorite), magnesium (saponite), or iron (non-
tronite).
Bentonite can be both physically and chemically
reactive. It shrinks or swells as it releases or absorbs
interstitial water or organic molecules, and it has
important cation exchange and chemical sorption
properties. Bentonite’s physical and chemical prop-
erties account for its usefulness in modifying fluid
viscosity or plasticity; it also has a variety of other
uses. Bentonites can be modified through chemical
treatment to enhance selected physical or chemical
properties.
Wyoming bentonites are suitable for use in an as-
mined condition.They are usedas anadditive in drill-
ing mudto increase viscosityand aidin theremoval of

drillhole cuttings. The clay also helps maintain cut
-
tings in suspensionand creates animpervious coating
on thewall of thedrillhole toprevent fluid lossduring
drilling. Southern bentonitescanbe modifiedtohave
properties similar to Wyoming bentonites, but their
use is generallyrestricted to otherapplicationssuchas
binding iron ore during pelletizing and the manufac-
ture of catalysts and no-carbon-required (NCR) copy
papers. Bentonites are also used to refine, decolor,
and purify oils and beverages; to manufacture fire re-
tardants; and as hydraulic barriers.
“Fuller’s earth” refers to clays (generally benton-
itic) suitable for bleaching and absorbent or other
special uses. The term was first used to describe mate-
rials used for cleansing or fulling wool (removing
lanolin and dirt), but it is now used more broadly to
include decolorizers or purifiers in filtering applica-
tions. Fuller’s earth products include cat litter, pesti-
cide and insecticide carriers, soil conditioners, light-
weight aggregate, and pharmaceuticals.
Mining and Processing
Most clay deposits are mined from open pits, al-
though some are mined by underground methods.
Open-pit mining generally involves the stripping of
overburden, excavation of the clay, and transport of
mined material to the processing plant. Some opera-
tions may require blasting.
The simplest operations involve excavation, trans-
port to the plant, drying, and shipment to the cus-

tomer. More complex operationsmayrequirethat the
mined material first be put into a slurry form for re-
moval of grit or sand, with transport to the plant by
pipeline. Clay slurries can be chemically or physically
treated to remove contaminants that contribute to
discoloration or poor chemical or physical perfor-
mance. They can then be filtered and dried prior to
packaging and shipment to the customer. Some clays
are put back into slurry form prior to shipment, de-
pending upon a customer’s needs.
Kyle L. Kayler
Further Reading
Bergaya, Faïza, Benny K. G. Theng, and Gerhard
Lagaly, eds. Handbook of Clay Science. New York:
Elsevier, 2006.
Chatterjee, Kaulir Kisor. “Clay.” In Uses of Industrial
Minerals, Rocks, and Freshwater. New York: Nova Sci-
ence, 2009.
Kogel, Jessica Elzea, et al., eds. “Clays.” In Industrial
Minerals and Rocks: Commodities, Markets, and Uses.
7th ed. Littleton, Colo.: Society for Mining, Metal
-
lurgy, and Exploration, 2006.
Global Resources Clays • 209