Mining, Coal
SIC 1220
NAICS 2121
Coal mining companies extract lignite, brown coal, Subbituminous coal, bituminous coal, or anthracite from the earth through surface or underground mining techniques. Industry firms may also administer mining operations and off-site preparation plants (also known as cleaning plants and washeries). The industry, particularly in North America, increasingly has touted its reclamation efforts to return soil and landscape to usable condition after all higher grade coal has been mined.
The global coal industry mines roughly 5 billion tons of material annually. Total recoverable reserves were estimated in the early 2000s at 1.083 trillion tons. Based on the consumption levels of 2004, industry analysts estimated that these reserves might last another 210 years. About 60 percent of recoverable reserves were located in three regions: the United States (25 percent), the Russian Federation (23 percent), and China (12 percent). Another 29 percent was found in Australia, India, Germany, and South Africa.
Despite challenges in some applications and in some areas of the world by other energy sources such as oil and natural gas, coal regained its worldwide reputation as a lower-cost primary fuel at the beginning of the twenty-first century. Global coal consumption through 2025 was expected to grow at a rate of about 1.5 percent a year, according to the U.S. Energy Information Administration (EIA). Areas of growth include Japan, and developing Asian countries where coal has always been regarded as an important source of heat and energy. The United States, where the George W. Bush administration touted coal as an inexpensive answer to the country's costly energy demands, is another growth area. On the other hand, the EIA predicted a drop in use among European and former Soviet Union countries.
Coal fuel supplied 24 percent of global energy needs in 2001, according to the EIA, down significantly from 27 percent in both 1995 and 1985 but slightly higher than 22 percent in 1999. Despite its increasing popularity in India and China, coal's proportion of total energy demand worldwide is expected to fall to 23 percent by 2025. By contrast, in 1950 coal had supplied about 60 percent of the world's energy needs.
India and China were responsible for 36 percent of global coal consumption in 1999, and these two countries alone were expected to account for 67 percent of the increase in demand for coal through 2025. Other countries expected to increase coal consumption markedly by 2020 include South Korea and Taiwan. This anticipated increase in coal consumption led to some optimism on the part of Australian experts who expected that the 2002 estimates of 3.7 billion metric tons annual consumption could substantially increase to 4.2 billion metric tons by 2010, according to Bloomberg News.
Most of the coal mined worldwide in 2004 was used to produce electric power, but other major coal applications included those related to iron and steel production and its use in various process industries like cement and textiles. Coal also remained an important source of home heat in many parts of the world.
Early in the twentieth century, North America and Europe were the two leading coal-producing regions. During the mid-twentieth century, though, production volume shifted to Asia, Australia, and South Africa. By the 1990s North American and Western European mining companies represented only an estimated 35 percent of industry output. Though coal deposits are distributed widely across the world, three regions control about 60 percent of coal reserves: the United States, the Russian Federation, and China. Other top coal-producing countries include Australia, India, Germany, and South Africa.
The coal industry near the end of the twentieth century was generally characterized by weak prices, increasing environmental controls, and labor strife; factors especially prevalent in developed nations. Industry success in the most developed regions was also blunted by increasing foreign competition, stagnant demand growth, and taxes on energy consumption. Producers in North America and Western Europe countered by raising productivity, increasing low-cost surface mining, consolidating, and taking advantage of new environmental technologies. Meanwhile, mining companies near economic growth regions like the Pacific Rim enjoyed market expansion and a relatively lenient regulatory climate. Guarded optimism in the industry by 2002 also came from expectations that coal needs by Japan through 2010 could result in more favorable contracts for long-term suppliers.
The five grades of mined coal are brown, lignite, sub bituminous, bituminous, and anthracite. Each category differs in moisture content, volatile matter, and amount of fixed carbon. As a result, each is distinguished by factors such as energy produced per unit of weight and the amount of pollutants released during burning.
Brown coal has an extremely high moisture content, sometimes as great as 60 percent or more. The material is relatively easy to mine and to ignite. However, it only produces around 6 million British thermal units (Btu) per ton, the lowest of all the coal grades. In addition, brown coal is difficult to store because it disintegrates when it is exposed to air and occasionally spontaneously combusts. It also has a high sulfur content, which makes it a major pollutant. Brown coal is most heavily mined in Central and Eastern Europe, although the largest reserves in the world are located in Victoria, Australia.
Lignite is similar to brown coal in that it is a brownish-black mineral with a high moisture content, about 30 percent to 40 percent water. It also deteriorates rapidly in air, has a high sulfur content, and is liable to spontaneously combust. Therefore lignite is used mainly to generate electricity in power plants that are located near mines. It was also used in the early 2000s as a substitute for wood in many third-world nations. In contrast to brown coal, lignite may generate 9 to 17 million Btu per ton. The largest lignite deposits in the world are located in the United States and Canada. Lignite is also mined extensively in Europe and the Commonwealth of Independent States (CIS).
Subbituminous coal is composed of 75 percent to 85 percent carbon and only 15 percent to 25 percent moisture. It produces 16 to 24 million Btu per ton and is used mainly to generate electricity. Its high moisture content and other negative properties make it less desirable than higher coal grades for most applications. Importantly, though, Subbituminous coal contains little sulfur. Furthermore, in some regions of the world, the material is relatively easy to extract through the use of low-cost surface mining techniques. As a result, consumption of this material proliferated in many regions of the world during the late twentieth century.
Bituminous coal, or soft coal, the most common type, is used in a range of applications. It has a deep, dull black appearance. Bituminous coal is composed of 80 percent to 90 percent carbon and about 10 percent to 20 percent moisture, and one ton of bituminous coal typically generates 19 to 30 million Btu. The material has a relatively low sulfur content, which enables it to burn more cleanly than lower grades. Because of its properties, bituminous coal is the principal steam coal used for generating electricity. It is also the primary cooking coal used in the steel-making process. The CIS, the United States, China, South Africa, India, and Australia are the leading producers.
The huge bituminous coal segment can be further categorized as low-, medium-, and high-volatile coal according to its moisture content and heating capacity. Low- and medium-volatility grade bituminous coal typically generates between 18 and 29 million Btu per ton. High-volatile coal, in contrast, usually produces 26 to 30 million Btu per ton. For comparison, a ton of bituminous coal, assuming an average 22 million Btu, produces about the same amount of energy as one cord of hardwood; 22,000 cubic feet of natural gas; or 160 gallons of fuel oil.
Anthracite, the highest grade coal, is mined in only a few countries and in low quantities. In the United States, most of this high-grade coal was has been extracted and exhausted for manufacturing purposes. The material burns with a hot, clean flame and contains only 3 percent moisture when it is mined. It also burns more slowly and uniformly than bituminous coal, which makes it excellent blast furnace material for the steel-making process.
The two principal coal mining techniques are surface and underground. Surface mining is usually practiced on relatively flat ground in situations where the desired coal is located less than 200 feet from the earth's surface. At mines where the coal is located on steep inclines, though, material may be excavated from open pits that can reach depths of several hundred feet. To get to the coal, miners must first remove the overburden, or strata, that covers the coal bed. Between 1 and 30 cubic yards of strata must be excavated for each ton of coal recovered. Dragline...
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