Encyclopedia of Global Resources part 77 ppt

The Bushveld intrusion accounts for almost 50 per
-
cent of the world’s production of vanadium.
Stephen C. Hildreth, Jr.
Further Reading
Best, Myron G. Igneous and Metamorphic Petrology.2d
ed. Malden, Mass.: Blackwell, 2003.
Brown, Michael, and Tracy Rushmer, eds. Evolution
and Differentiation of the Continental Crust. New York:
Cambridge University Press, 2006.
Evans, Anthony M. Ore Geology and Industrial Minerals:
An Introduction. 3d ed. Boston: Blackwell Scientific
Publications, 1993.
Naldrett, AnthonyJ. MagmaticsSulfide Deposits:Geology,
Geochemistry, and Exploration.Berlin: Springer, 2004.
Schmincke, Hans-Ulrich.“Magma.” In Volcanism.New
York: Springer, 2004.
Young, Davis A. Mind over Magma: The Story of Igneous
Petrology. Princeton, N.J.: Princeton University
Press, 2003.
Web Site
U.S. Geological Survey
Magma, Lava, Lava Flows, Lave Lakes
/>description_lava_flows.html
See also: Earth’s crust; Igneous processes, rocks, and
mineral deposits; Ophiolites; Pegmatites; Plutonic
rocks and mineral deposits; Vanadium; Volcanoes.
Magnesium
Category: Mineral and other nonliving resources
Where Found
Magnesium is a widespread and abundant element.

Magnesium chloride and magnesium sulfate are pres-
ent in dissolved form in seawater and underground
brines—these sources accounted for 43 percent of
U.S. magnesium compound production in 2008.
Magnesium is also found in many minerals, notably
magnesite (MgCO
3
), dolomite (CaMg (CO
3
)
2
), and
brucite (Mg(OH)
2
). China, Russia, Israel, Kazakh-
stan, Canada, and Brazil are among the main produc-
ers. For a number of years, the United States has with
-
held its magnesium production statistics to avoid
disclosure of companies’ proprietary data.
Primary Uses
Magnesium is used principally in alloys, refractory
materials (60 percent of U.S. use), paper, fertilizer,
chemicals, and pyrotechnics. As a compound, it can
be used as an additive to food, in medicine, and as a
sedative.
Technical Definition
Magnesium (abbreviated Mg), atomic number 12, be-
longs to Group IIA of the periodic table of the ele-
ments (alkaline-earth metals). It has three stable iso-

topes and an average molecular weight of 24.312.
Pure magnesium is a silver-white, ductile metal that is
malleable when heated. A chemically active element,
magnesium is a potent reducing agent. Its specific
gravity is 1.738 at 20° Celsius, its melting point is 651°
Celsius, and its boiling point is 1,100° Celsius.
Description, Distribution, and Forms
Magnesium in the form of powder or ribbons readily
ignites when heated, burning with an intense white
light and releasing large amounts of heat while form-
ing magnesia (magnesium oxide, MgO). Magnesium
reacts with organic halides to produce Grignard re-
agents, an important class of chemical compounds
used in the laboratory.
Magnesium is an alkaline-earth metal, a class of
hard, heavy metals that are strongly electropositive
and chemically reactive. It is the eighth most abun-
dant element; its concentration in the lithosphere is
20,900 grams per metric ton, and the percentage of
its ions in seawater is 0.1272. Magnesium’s density
(only two-thirds that of aluminum) and the ease with
which the element can be machined, cast, forged,
and welded contribute to its commercial applica-
tions, as do the refractory properties of some of its
compounds. China is the leading producer of pri-
mary (mined and processed) magnesium (627,000
metric tons in 2007), accounting for nearly 85 per-
cent of magnesium production in the world. Russia
and Canada are the world’s other leading producers.
However, from 2003 to 2007, Canadian production

declined dramatically from 78,000 to 16,300 metric
tons.
Magnesium isone of themost commonminerals in
the Earth’s crust; its principal commercial source,
however, is seawater. Extensive terrestrial deposits of
magnesium are also found in the form of magnesite
and dolomite. Magnesite, a magnesium carbonate,
occurs as a hydrothermal alteration of serpentine,
708 • Magnesium Global Resources
(Mg,Fe)
3
Si
2
O
5
(OH)
4
, a vein filling and a replacement
mineral in carbonate rocks such as dolostone. Dolo-
mite, or calcium magnesium carbonate, is the predom-
inant mineral in dolostone, a widespread sedimentary
rock similar tolimestone. Most dolomites are thought
to haveoriginated from partialreplacement of calcium
in limestone by magnesium. Magnesium occurs in na-
ture as a component of several common minerals. Im-
portant ores include magnesite, a white or grayish
mineral found in crystalline or porcelain-like masses;
dolomite, a white mineral that resembles limestone;
and brucite, a pearly foliated or fibrous mineral that
resembles talc. Magnesium silicates are found in as-

bestos, serpentine, and talc. Magnesium chloride and
magnesium sulfate occur in dissolved form in sea
water and natural underground brines. Magnesium is
also a constituent of chlorophyll in green plants.
History
Sir Humphry Davy discovered magnesia in 1808. In
1828, Antoine Bussy isolated pure magnesium by
chemical reduction of the chloride, and in 1833, Mi
-
chael Faraday isolated magnesium electrolytically.
The earliest commercial production of the metal may
Global Resources Magnesium • 709
Data from the U.S. Geological Survey, . U.S. Government Printing Office, 2009.Source: Mineral Commodity Summaries, 2009
150,000
105,000
350,000
350,000
170,000
150,000
600,000
Withheld
140,000
Metric Tons of Magnesium Content
2,500,0002,000,0001,500,0001,000,000500,000
United States
Slovakia
Russia
North Korea
India
Greece

Spain
Turkey
Other countries
U.S. data were withheld to avoid disclosure of company proprietary data.Note:
140,000
200,000
100,000
2,000,000China
Brazil
Austria
Australia
Magnesium Compounds: World Mine Production, 2008
have been in France during the first half of the nine-
teenth century, where a modification of the Bussy
method wasemployed. Atthis time, magnesiummetal
was used primarily in photography. Around 1886,
Germany developed an improved production process
based on an electrolytic cell method devised by Rob-
ert Bunsen in 1852. Germany became the world’s sole
source for elemental magnesium. Magnesium alloys
were usedin Germany inthe early1900’s inaircraft fu-
selages, engineparts, and wheels.In 1915,when a war-
time blockade of Germany by the British interrupted
the elemental magnesium trade, magnesium produc-
tion began in the United States. Large-scale use of
dolostone as a refractory material also commenced
during World War I. In 1941, Dow Chemical Corpora-
tion introduced its process for extracting magnesium
from seawater.
Obtaining Magnesium

Magnesium is obtained principally from seawater
through theDow seawater process.The water is treated
with lime to produce magnesium hydroxide as a pre-
cipitate. This precipitate is mixed with hydrochloric
acid to form magnesium chloride; the chloride, in
turn, is fused and electrolyzed, producing magne-
sium metal and chlorine gas. From a liter of seawater,
approximately 10milligrams ofmagnesium can beex-
tracted. Anothercommon methodfor obtainingmag-
nesium is the ferrosilicon (Pidgeon) process, which
uses dolomite as a raw material. The dolomite is
heated to produce magnesia, which is then reduced
with an iron-silicon alloy.
Uses of Magnesium
Dead-burned magnesite, produced by heating the
mineral in a kiln at 1,500° to 1,750° Celsius until it
contains less than 1 percent carbon dioxide, is a re-
fractory material.Able towithstand contactwith often
corrosive substances at high temperatures, refractory
materials are used to line furnaces, kilns, reaction ves
-
sels, and ladles used in the cement, glass, steel, and
metallurgical industries. Magnesia refractories are
710 • Magnesium Global Resources
Data from the U.S. Geological Survey, . U.S. Government Printing Office, 2009.Source: Mineral Commodity Summaries, 2009
U.S. data were withheld to avoid disclosure of company proprietary data.Note:
18,000
700,000
30,000
20,000

35,000
2,000
3,000
Withheld
Metric Tons
750,000600,000450,000300,000150,000
Ukraine
Kazakhstan
Israel
China
Brazil
Russia
Serbia
United States
Magnesium Metal: World Primary Production, 2008
materials particularly suited for the basic oxygen fur
-
naces used in steelmaking. Dead-burned dolomite,
produced by heating dolostone or dolomitic lime-
stone at about 1,500° Celsius, isalso a refractory mate-
rial used for lining metallurgical furnaces.
In its elemental state, magnesium is soft and weak;
its alloys, however, are sturdier and have a variety of
uses. Magnesium is used extensively as an alloy metal,
particularly in combinationwith aluminum, zinc,cad-
mium, and manganese. Magnesium alloys in general
are lightweight, fatigue-resistant, free from brittle-
ness, and able to withstand bending stresses; these
qualities make magnesium alloys ideal for jet-engine
parts, rockets and missiles, luggage frames, cameras,

optical instruments, scientific equipment, and porta-
ble power tools. Duralumin, a lightweight alloy of alu-
minum, copper, magnesium, and manganese, is duc-
tile and malleable before its final heat treatment;
afterward, its hardness and tensile strength are in-
creased. Its properties make duralumin especially
useful to the aircraft industry. Magnalium, an alloy of
aluminum andmagnesium thatis lighterand easierto
work than aluminum, is used in metal mirrors and sci-
entific instruments.
Pure magnesium is used in incendiary bombs, sig-
nals and flares, thermite fuses, and other pyrotechnic
devices. It is an important component of photo-
graphic flashbulbs, a deoxidizing agent used in the
preparation of some nonferrous metals, a rocket and
missile fuel additive, and an agent for chemical syn-
thesis. Magnesium reacts with organic halides to form
Grignard reagents, an importantclass of extremely re-
active chemical compoundsthat are used in synthesiz-
ing hydrocarbons, alcohols, carboxylic acids, and
other compounds. Magnesium compounds are used
in chemicals, ceramics, cosmetics, fertilizer, insula-
tion, paper, leather tanning, and textile processing.
Epsom salts (magnesium sulfate heptahydrate), milk
of magnesia (magnesium hydroxide), and citrate of
magnesium are used in medicines. Caustic-calcined
magnesia (magnesite heated to between 700° and
1,000° Celsius to drive off 2 to 10 percent of its carbon
dioxide) is mixed with magnesium chloride to create
oxychloride (sorel) cement. This cement is used for

heavy-duty floorings, stucco, and fireproof building
materials. Dolostone, a rock composed chiefly of do-
lomite, is used as a building stone as well as a refrac-
tory material.
Magnesium is an essential element in all plants
and animals. In green plants, it is a component of
chlorophyll; in animals, it plays a role in carbohydrate
metabolism and is an important trace element for
muscle, nerve tissue, and skeletal structure. Serious
dietary deficiencies of magnesium can bring on such
symptoms as hyperirritability and soft-tissue calcifica-
tion.
Karen N. Kähler
Further Reading
Friedrich, HorstE., andBarry L.Mordike, eds. Magne-
sium Technology: Metallurgy, Design Data, Applica-
tions. New York: Springer, 2006.
Greenwood, N. N., andA. Earnshaw.“Beryllium, Mag-
nesium, Calcium, Strontium, Barium, and Ra-
dium.” In Chemistry of the Elements. 2d ed. Boston:
Butterworth-Heinemann, 1997.
Henderson, William. “The Group 2 Elements: Beryl-
lium, Magnesium, Calcium, Strontium, Barium,
and Radium.”In Main GroupChemistry. Cambridge,
England: Royal Society of Chemistry, 2000.
Kogel, Jessica Elzea, et al., eds. “Magnesium Minerals
and Compounds.” In Industrial Minerals and Rocks:
Commodities, Markets, and Uses. 7th ed. Littleton,
Colo.: Society for Mining,Metallurgy,and Explora-
tion, 2006.

Manning, D. A. C. Introduction to Industrial Minerals.
New York: Chapman & Hall, 1995.
Seelig, Mildred S., and Andrea Rosanoff. The Magne-
sium Factor. New York: Avery, 2003.
Silva, J. J. R.Fraústo da, and R. J. P. Williams. “The Bio-
logical Chemistry of Magnesium: Phosphate Me-
tabolism.” In The Biological Chemistry of the Elements:
The Inorganic Chemistry of Life. 2d ed. New York: Ox-
ford University Press, 2001.
Web Sites
Natural Resources Canada
Canadian Minerals Yearbook, Mineral and Metal
Commodity Reviews
/>indu/cmy-amc/com-eng.htm
U.S. Geological Survey
Magnesium: Statistics and Information
/>commodity/magnesium
See also: Alloys; Limestone; Metals and metallurgy;
Steel.
Global Resources Magnesium • 711
Magnetic materials
Category: Mineral and other nonliving resources
Naturally occurring magnetic materials have been
known and used for centuries. Materials that can be
temporarily magnetized by an electrical current are
widely used in applications ranging from simple elec-
trical appliances and motors to sophisticated computer
systems.
Definition
Substances that respond to a magnetic field are called

magnetic materials. The most common magnetic ma-
terials are iron (Fe), cobalt (Co), nickel (Ni), and
their alloys. These three elements belong to Group
VIIIB of the periodic table. Four varieties of magne-
tism are recognized: ferromagnetism, ferrimagnetism,
diamagnetism, and paramagnetism. Iron, cobalt,
nickel, gadolinium (Gd), and chromium dioxide
(CrO
2
) are examples of ferromagnetic materials.
Ferroferric oxide (Fe
3
O
4
) is a ferrimagnetic material.
Feeble magnetism isexhibited in certain alloys and el-
ements. A substance that is magnetized in the oppo-
site direction of the external magnetic field is called a
diamagnetic material. Some examples are gold, silver,
copper, and quartz. A substance that is magnetized in
the same direction as the external magnetic field is
called a paramagnetic material. Certain types of spe-
cial alloys are paramagnetic.
Overview
Magnets attract materials or objects made of iron
(and steel), cobalt, and nickel. A magnet’s power is
strongest atits twoends, called poles. One iscalled the
north pole andthe other the southpole. A compass is,
in principle, a magnet pivoted at its center which ori-
ents itself in the direction of the Earth’s magnetic

field. A compasshas long been one ofthe most impor-
tant navigational instruments onboard ships and air-
planes.
The largest deposits of the mineral magnetite
(Fe
3
O
4
), magnetic iron ore, are found in northern
Sweden. Sizable deposits of magnetite are also found
in Australia, Italy, Switzerland, Norway, the Ural
Mountains in Russia, and several other regions. In the
United States, magnetite is found in Arkansas, New
Jersey, and Utah. The Precambrian rocks of the
Adirondacks contain large beds of magnetite.
The ancient Chinese discovered that a freely sus-
pended lodestone (naturally occurring polarized
magnetite) would always orient itself in the same geo-
graphical direction. This observation led to the devel-
opment of the compass. In the West, historical rec-
ords of magnetic materials date back to the ancient
Greeks. By 500 b.c.e., the Greeks had discovered that
certain rocks were attracted to iron nails on ships and
boats. In 1600, William Gilbert, an English doctor,
published De Magnete, in which he identified the
Earth itself as a giant magnet.
A number of fundamental advances in the practical
applications of magnetism occurred
in the early nineteenth century. In
1820, the Danish scientist Hans

Christian Øersted discovered that a
magnetic needle could be deflected
by a current in a wire. In 1823, En-
glish scientist William Sturgeon
wound an insulated copper wire
around an iron bar and discovered
that the iron bar became a strong
magnet. Thusthe electromagnet was
born. In 1821, Michael Faradaydem-
onstrated the first electricmotor, the
“magnetic rotation of a conductor
and magnet.” In 1828, Joseph Henry
produced silk-covered wires and de-
veloped more powerful electromag-
nets.
Magnetic materials have a tremen
-
dous range of uses, from huge indus
-
712 • Magnetic materials Global Resources
Magnetite is a type of magnetic material. (USGS)
trial electromagnets to the use of “magnetic bubbles”
in highlyadvanced computer systems.Magnetic mate-
rials are classified into three major categories: hard,
soft, and memory-quality materials. Hard magnetic
materials have applications as permanent magnets in
small motors, small direct-current generators (dyna-
mos), measuring instruments, and speaker systems.
Soft magneticmaterials—those that are influenced by
external fields—are widely used in transformers, gen-

erators, motors, and alternators of all sizes and rating
capacities. Almost all appliances used in homes and
industry, from shavers to washing machines to relays,
contain electromagnets with soft magnetic materials.
The materials used most often are iron, silicon-iron
combinations, nickel-iron alloys, and ferrites. Mem-
ory-quality magnetic materials are used to record and
store data, either in analog or digital form. Examples
are magnetic tapes, drums, and disks.
Huge electromagnets are used to move automo-
biles or other metal objects in automobile recycling
yards and junkyards. Gigantic electromagnets are es-
sential to nuclear fusion experiments. Magnetic-
levitation (maglev) trains are held above the ground
by superconducting electromagnets. Superconduct-
ing electromagnets are also used in magnetic reso-
nance imaging(MRI) bodyscanners, devicesthat pro-
duce detailed images of the inside of the body and
provide diagnostic data to doctors.
Mysore Narayanan
See also: Cobalt; Iron; Nickel; Steel.
Manganese
Category: Mineral and other nonliving resources
Manganese is one of the most abundant elements in
the crust of the Earth and is usually a minor constitu-
ent in ordinary rocks. Its chemical and physical prop-
erties are similar to those of iron, and the two metals of-
ten occur together.
Where Found
Manganese oxides are abundant in nature; however,

large, high-grade deposits are relatively rare. Concen-
trations of the element approximately 250 to 500
times greater than the average crustal abundance are
required to produce ore. All the major ore deposits
are sedimentary in origin and consist of various man
-
ganese oxide minerals. The major deposits of the
world are sedimentary in origin and are located in
Russia, Africa, and Brazil. The five leading manga-
nese-producing countries in 2007 were South Africa,
Australia, China, Gabon, and Brazil. Together these
countries account for 70 percent of the world’s total
output.
Primary Uses
Manganese playsa majorrole insteel production. Sec-
ondary uses of this mineral are in alloys, batteries, fer-
tilizers, and the manufacture of chemicals.
Technical Definition
Manganese (atomic number 25, chemical symbol
Mn) is thetwelfth most abundantelement in the crust
of the Earth and makes up about 0.1 percent of the
crust by weight. In its pure state, which does not occur
in nature, it is a hard, brittle metal with a gray color, a
melting point of 1,260° Celsius, a boiling point of
1,900° Celsius, and a density of 7.2 grams per cubic
centimeter. It resembles iron in many of its properties
and has oxidation states of +2, +3, +4, +6, and +7. As is
true of iron, the reduced +2 form is quite soluble un-
der near-surface conditions and is carried in solution
by stream and groundwater.

Description, Distribution, and Forms
Because of itsgreat crustal abundance,small amounts
of manganese, in the form of dark-colored oxide min-
erals, are common inmost rocks. Forcommercial pro-
duction, however, ore bodies averaging at least 35 per-
cent manganese and containing millions of metric
tons of the metal are required. The highest-grade ore
contains more than 48 percent manganese. Such de-
posits are not common. All the known major deposits
are of sedimentary origin. There are several ore min-
erals of manganese, but the most important are all ox-
ides: pyrolusite (MnO
2
), psilomelane (Mn
2
O
3
2H
2
O),
and manganite (Mn
2
O
3
H
2
O).
Although manganese occurs in several oxidation
states, the reduced +2 is most common in subsurface
waters because of its solubility. Manganese oxide min-

erals precipitate readilyat a boundary betweenoxidiz-
ing and reducing conditions, such as the reducing
groundwater percolating intowell-oxygenated stream
water. As a result, manganese oxide coatings on stream
pebbles and rocks are common, so common that they
usually go unnoticed. Similar black coatings are also
Global Resources Manganese • 713
common in arid regions in the form of “desert var-
nish” and indeep freshwater lakes.In the ocean, large
manganese oxide nodules occur. Changes from re-
ducing to oxidizing conditions have been implicated
as important in producing all of these common sur-
face forms of manganese oxide, but it is also likely
that manganese-oxidizing bacteria play an important
role, particularly fordesert varnish andstream pebble
coatings.
The Challenger expedition in the 1870’s discovered
manganese oxide nodules in the deep-ocean basin,
but their widespread occurrence and abundance did
not become known until sampling in the 1960’s. These
nodules are black and rounded to irregular lumps of
pebble and cobble size. They exist in all the world’s
oceans but are irregularly distributed. The origin of
the nodules has been the subject of much research.
Evidence indicates that the nodules are continually
growing at a very slow rate by the addition of manga
-
nese and other metals from seawater. The absence of
sediment to muddy the water increases their rate of
precipitation, a fact which explains why most nodules

are found only in the deep-ocean basins, far removed
from sediment eroded from landmasses.
Manganese is considered to be one of the least toxic
of the trace elements. Several thousand parts per mil-
lion of manganese in the diet of mammals and birds
are usually required to develop symptoms of toxicity.
The exact amount that is toxic varies from species to
species and is also dependent on the form in which
manganese isconsumed andthe ageof theindividual.
The main symptom reported is a reduced rate of
growth because of appetite depression.
While very high levels of manganese are required
to produce toxic effects from oral consumption,
mammals, including humans, appear to have a con-
siderably low tolerance to the inhalation of manga-
nese dusts. High levels of such dusts can occur in oc-
cupational settings such as steel mills, manganese
mines, and certain chemical industries. The lungs ap
-
parently act as asink from which manganese is contin
-
ually absorbed.The main toxiceffect produced is a se
-
714 • Manganese Global Resources
Data from the U.S. Geological Survey, . U.S. Government Printing Office, 2009.Source: Mineral Commodity Summaries, 2009
2,200,000
1,300,000
2,800,000
1,600,000
940,000

130,000
3,000,000
480,000
1,400,000
Metric Tons Gross Weight
3,500,0003,000,0002,500,0002,000,0001,500,0001,000,000500,000
Ukraine
India
Gabon
China
Brazil
Australia
Mexico
South Africa
Other countries
Manganese: World Production, 2008
rious neurological disease with many symptoms in
common with Parkinson’s disease. Such manganese-
induced neurotoxicity has been the subject of consid-
erable interest because manganese compounds have
been used in gasoline as a replacement for lead com-
pounds.
History
Manganese oxide has been known since antiquity,
when it was used in glass manufacture, but the metal
itself was not isolated until 1770. There was little inter-
est in themetal until 1856, whenit was discoveredthat
manganese could be used to remove sulfur and oxy-
gen impurities as a slag from molten steel. All steel up
to this time had been extremely brittle because of the

presence of these impurities. An important world
market for manganese quickly developed. The
world’smajor deposit of manganesewas discovered in
the Nikopol’ Basin in Ukraine in the 1920’s. Subse-
quently, this area became the world’s major producer.
In the nineteenth century, the United States was self-
sufficient in manganese, but these deposits are all ex-
hausted.
Obtaining Manganese
Two types of sedimentary deposits account for
most of the world’s production. The first type,
illustrated by the world’s largest deposit at
Nikopol’ insouthern Ukraine,consists ofman-
ganese in the form of earthy masses and nod-
ules of manganese oxide in beds of sandy clay
and limestone. This type of deposit is thought
to have originated by a two-step process. First,
manganese in its reduced form, derived from
the weathering and erosion of continental ar-
eas, is carried by streams in solution to the
open sea. Second, in the sea, reduced manga-
nese undergoes oxidation,causing it toprecip-
itate as manganese oxide minerals because of
the strongly oxidizing conditions in the open
ocean.
The second important type of deposit has
resulted from the weathering of rocks contain-
ing small amounts of manganese silicate and
carbonate minerals. These minerals are resis-
tant to weathering, so their relative abundance

increases as the less resistant minerals are dis-
solved. Eventually, a large, high-grade deposit
of manganese may be produced. Geologists
use the term “residual” to refer to any type of
mineral deposit in which the valuable material has
been concentrated by weathering. Important manga-
nese deposits of this type occur in Brazil and China.
Mining companies became interested in deep-sea
manganese nodules in the 1960’s and 1970’s. The
richest area seems to be a portion of the deep Pacific
floor extending 4,800 kilometers eastward from the
southern tip of Hawaii. There are places in this region
in which the nodules literallycover the seafloor.Inter-
est in the nodules is high because, in addition to aver-
aging 25 percent manganese, they also average about
1.3 percent nickel, 1 percent copper, 0.22 percent
cobalt, and 0.05 percent molybdenum, all of which
could be recovered as by-products. Between 1962
and 1978 several international consortia spent nearly
$100 million studying methods for mining the nod-
ules. At least two promising methods were identified,
but no commercial mining of the deep seafloor oc-
curred.
Uses of Manganese
Most manganese is used during the manufacture of
steel to remove sulfur and oxygen. There are no prac-
tical replacements for manganese in this essential
role. Approximately 90 percent of the manganese
Global Resources Manganese • 715
Source: Mineral Commodity

Summaries, 2009
Data from the U.S. Geological Survey,
. U.S. Government Printing Office, 2009.
Construction
29%
Machinery
10%
Transportation 10%
Misc.
iron and
steel uses
51%
U.S. End Uses of Manganese
that isconsumed eachyear inthe United States is used
in the manufacture of steel. Manganese is also used as
a component in certain aluminum alloys and in dry
cell batteries. Minor amountsare used as a colorant in
glass, in fertilizers, and as a gasoline additive.
Gene D. Robinson
Further Reading
Adriano, Domy C. “Manganese.” 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. “Manganese,
Technetium, and Rhenium.” In Chemistry of the
Elements. 2d ed. Boston: Butterworth-Heinemann,
1997.
Howe, P. D., H. H. Malcolm, and S. Dobson. Manga-
nese and Its Compounds: Environmental Aspects.Ge-

neva, Switzerland: World Health Organization,
2004.
Klimis-Tavantzis, Dorothy J., ed. Manganese in Health
and Disease. Boca Raton, Fla.: CRC Press, 1994.
Kogel, Jessica Elzea, et al., eds. “Manganese.” In Indus-
trial Minerals and Rocks: Commodities, Markets, and
Uses. 7th ed. Littleton, Colo.: Society for Mining,
Metallurgy, and Exploration, 2006.
Priest, Tyler. Global Gambits: Big Steel and the U.S. Quest
for Manganese. Westport, Conn.: Praeger, 2003.
Sigel, Astrid, and Helmut Sigel, eds. Manganese and Its
Role inBiological Processes. NewYork: Marcel Dekker,
2000.
Wolf, Karl H., ed. Handbook of Strata-Bound and
Stratiform Ore Deposits. Vol. 2. New York: Elsevier Sci-
entific, 1986.
Web Sites
Natural Resources Canada
Canadian Minerals Yearbook, Mineral and Metal
Commodity Reviews
/>indu/cmy-amc/com-eng.htm
U.S. Geological Survey
Manganese: Statistics and Information
/>commodity/manganese
See also: Bessemer process; Clean Air Act; Food
chain; Iron; Marine mining; Sedimentary processes,
rocks, and mineral deposits; Steel.
Manhattan Project
Category: Historical events and movements
The Manhattan Engineer District was created in Au-

gust, 1942, to sponsor the Manhattan Project, a top-
secret effort to produce the atomic bomb in time to be
used during World War II. The Manhattan Project’s
legacy, in addition to the destruction wrought by the
two atomic bombs the United States dropped on Japan,
includes the proliferation of nuclear weapons and the
peacetime development of nuclear power plants.
Background
During World War II, the United States, Germany,
Great Britain, the Soviet Union, France, and Japan all
had projects toexamine the feasibility ofconstructing
an atomic bomb. Japanese progress was minimal, and
French progress halted with the German occupation
of France. American efforts were spurred on by the
British and by scientists such as Leo Szilard, Eugene
Paul Wigner, and Enrico Fermi, who fled oppression
in Europe. Since the Germans had a considerable
head start in addition to formidable industrial and
scientific resources, many feared that Adolf Hitler
would develop the atomic bomb first.
Developing and Constructing the Bomb
Enough work had been done prior to the Manhattan
Project to convince those involved that the problems
of producing a bomb could probably be surmounted
if sufficient resourceswere made available.Because of
the war mobilization, the Army Corps of Engineers
was managing construction contracts amounting to
$600 million a month, and funds for the top-secret
Manhattan Project were hidden within that amount.
The initial cost estimate for the project was $133 mil-

lion; the actual cost was about $2 billion.
Before the Manhattan Project, American atomic
bomb research was conducted by various scientists at
several universities. Progress was intermittent. On
September 17, 1942, Colonel (soon to be General)
Leslie Richard Groves was appointed to head the
Manhattan EngineerDistrict. Groves wasan engineer,
and his supervision of the building of the Pentagon
had demonstrated a knack for untangling bureau-
cratic messes. He was regarded as arrogant and abrupt
but alsoas aperson whocould getthe jobdone right.
Under Groves, the Manhattan Project proceeded
716 • Manhattan Project Global Resources
at breakneck speed. Factories were built before the
machines they would house were fully worked out,
and full-scale machines were built before prototypes
were fully tested. While this approach did not always
work, it worked well enough. At Hanford, Washing-
ton, fifty thousand construction workers built three
large nuclear reactors to produce plutonium along
with three separation plants to remove the plutonium
from the used reactor fuel. A huge gaseous diffusion
plant and an electromagnet separation plant were
built at Oak Ridge, Tennessee, to separate uranium
235 from the more common uranium 238. Because of
a copper shortage, more than 12,000 metric tons of
silver were borrowed from the federal treasury and
made into conductors for the electromagnets. The
design and construction of the bombs were done at
the Los Alamosweapons laboratory,headed by J. Rob

-
ert Oppenheimer.
At the project’s peak, more than 160,000 workers
were employed at twenty-five sites. Most of the
Manhattan Project workers knew only that they were
working on something very important and that it
might help end the war. Many of those who knew that
they were working on the atomic bomb hoped that it
would help end the war and that it might make future
wars unthinkable.
Charles W. Rogers
See also: Isotopes, radioactive; Nuclear energy; Nu-
clear waste and its disposal; Plutonium; Uranium.
Manufacturing, energy use in
Category: Obtaining and using resources
Industrial processes consume roughly 46 percent of
world energy each year. In the United States, about 80
percent of that energy goes to the basic production in-
dustries of iron, steel, aluminum, paper, chemicals,
and nonmetallic minerals (cement, brick, glass, and
ceramics).
Background
The sophistication of a society’s technology can be
judged by what it can make and how efficiently it can
make those items. In ancient civilizations, rock and
wood yieldedto metal,fired pottery, andglass. Bronze
and brass weapons swept aside stone. Then iron and
steel replaced the softer metals.
Muscle power was sporadically aidedby water power
in antiquity, but the intensive use of water power be-

gan in Europe in the Middle Ages. Besides grinding
flour, water mills supplied power for large-scale weav-
ing, for sawmills, and for blowing air onto hot metal
and hammering the finished metals. The gearing re-
quired to modify the motion and move it throughout
a workshop also applied to wind power, and Dutch
mills led manufacturing in the late Middle Ages.
A series of inventions led to James Watt’s improved
steam engine in 1782. The immediate goal was pump-
ing water out of coal mines, but steam engines also al-
lowed factory power to be located anywhere. Steam-
powered locomotives allowed materials to be more
easily moved to those locations.
At the beginning of the twentieth century, small
electric motors allowed a further decentralization of
industry. A small shop required only a power cable,
Global Resources Manufacturing, energy use in • 717
Robert Oppenheimer, the scientific director of theManhattan Project
and architect of the atomic bomb, left, speaks with General Leslie
Groves, the military director of the Manhattan Project, in Alamo-
gordo, New Mexico. (Popperfoto/Getty Images)