COAL INDUSTRY

Coal is a rock that is made up mostly of carbon. Because it is combustible, it is used as a fuel that can provide light, heat, and power. Most coal was formed during the Carboniferous Period and the Permian Period, approximately 250-to 350-million years ago. Warm moist swampy areas became covered with vegetation that decomposed into peat, which in time and under pressure turned into different types of coal, depending on the exact conditions. There are four major grades of coal (from softest to hardest): lignite, subbituminous, bituminous, and anthracite. Bituminous coal is the type most often produced in the United States.

The use of coal may trace back to China around 1000 b.c.. The Romans may have used coal in the fifth century a.d., and there references to the use of coal in medieval Europe. However, there was no widespread use of coal until the Englishman Abraham Darby began to burn it as fuel for his furnace. The invention of the steam engine provided another important use for this product.

By 1745 coal began to be commercially mined in North America, but it was not until the American Revolution(1775–83) brought a halt to the importation of coal from Europe that the American coal industry began to expand at a rapid pace. By the 1840s there were numerous small mining companies in the northeastern United States. The development of the steam locomotive in the second half of the nineteenth century improved transportation and distribution of coal over long distances. The Industrial Revolution also contributed greatly to the expansion of the coal mining industry in the United States.

By the 1920s the coal industry experienced a decline in coal processing, largely because of over-expansion. Many mines closed and as many as 150,000 coal mining related jobs were lost. As other fuels such as petroleum and natural gas became popular, coal continued to drop in price. An act of Congress called the Bituminous Coal Act (1937) attempted to improve the stability of the coal industry.

The 1940s saw the conversion of steam locomotives to diesel fuel, but the loss of this use of coal was replaced by greater use of coal in electric power plants. Throughout the rest of the twentieth century, electric power plants continued to be a major consumer of coal. More efficient methods of shipping coal by train that were introduced in the 1960s allowed greater quantities to be moved across the country. Oil shortages in 1973–74 also caused the demand for coal to increase. Several developments in the 1970s limited productivity and profits although they forced coal operators to become better corporate citizens. Among them were stricter federal regulations on safety, labor practices, and environmental pollution, all areas where coal companies had a questionable reputation. In addition, other fuel resources such as nuclear power came into use as alternatives to coal.

Two very common ways to mine coal on the surface are strip mining and auger mining. However, the most hazardous method to mine coal is under-ground. Coal mining was always a dangerous under-taking and some of the early coal operators took advantage of mine workers. Dangers included mineshaft collapse, explosions, and exposure to coal dust, which could cause "black-lung disease." In 1890 miners banded together to found their own union, the United Mine Workers (UMW), to improve safety and working conditions. The union also improved wages; the UMW remained active through the end of the twentieth century. However, though automation and advancements in technology reduced the dangers, elements of risk would always be present.

The 1980s saw some profit increases for coal producing companies through advancements in technology that improved efficiency and productivity. In the 1990s growth in coal production remain slow but steady, although the numbers of people employed in the coal industry continued to drop. The major use of coal in the United States continued to be the production of electric power. In the 1990s coal resources in the United States were projected to last for another 250 years. According to these estimations, this natural resource would continue to be utilized as a means of power for generations to come.

See also: United Mine Workers

FURTHER READING

Heil, Scott, and Terrance W. Peck, eds. Encyclopedia of American Industries, 2nd ed., Vol 2. Detroit: Gale Research, 1997.

Stearns, Peter N., and John H. Hinshaw. The ABC- CLIO World History Companion to the Industrial Revolution. Santa Barbara, CA: ABC-CLIO, Inc., 1996, s.v. "Coal Miners."

Stearns, Peter N., and John H. Hinshaw. The ABC- CLIO World History Companion to the Industrial Revolution. Santa Barbara, CA: ABC-CLIO, Inc., 1996, s.v. "United Mine Workers."

"Assessing the Coal Resources of the United States," [cited February 1, 1999] available from the World Wide Web @ energy.usgs.gov/factsheets/nca/nca.html/.

The Business of Coal. Chicago: Arthur Andersen and Company, 1981.

mine drainage Mining activities often result in the production of large amounts of waste rock. These dumps of rock, or tailings, contain all the minerals that are not required, together with small quantities of the ore minerals that are the object of mining activities. Where metals are mined, the ore minerals in the waste are typically sulphides (e.g. pyrite, FeS₂, and sphalerite, ZnS). Breakdown of sulphide minerals occurs when an increased surface area of mineral is available to interact with atmospheric oxygen and bacteria, and can result in the formation of acid and transport of the metals away from the tailings dump.

When sulphide-rich minerals are exposed to oxygen, they start to break down as a result of hydrolysis of the metal ion. For example,Zn²⁺ + H₂O = ZnOH⁺ + H⁺.

This reaction generates acidity (H⁺). Breakdown of pyrite, FeS₂, a common sulphide mineral, results in a very acidic solution:2FeS₂ + 7.50₂ + 4H₂O = Fe₂O₃ + 4SO₄²⁻ + 8H⁺.

Most metals are soluble in acidic solutions, and large amounts of metals can therefore be dissolved in such drainage. When the acidity of these fluids is decreased, for example by mixing with river water, the metals become less soluble and start to precipitate out of solution. This results in the red coloration that is typically seen where acidic mine drainage comes into contact with river water and iron oxyhydroxides, FeOOH, are precipitated.

Elizabeth H. Bailey

drainage in mining, removal of water seeping into shafts and other underground mine workings from the surrounding ground. Unless seeping water is removed continually, it may endanger haulage and mining equipment, weaken supporting structures, and, in some instances, flood the mine completely. Water in a mine is drained into sumps, or reservoirs, usually excavated below the lowest working level of the mine, and is then removed by pumps. Methods to minimize seepage include the sealing of visible fissures through which water enters and the injection of concrete into the ground surrounding the shafts.