Date: Wed, 19 Nov 1997 23:32:28 GMT Server: NCSA/1.5.2 Last-modified: Mon, 24 Feb 1997 22:16:22 GMT Content-type: text/html Content-length: 13593 Zeigler's Glossary of Terms

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Acid Rain. Refers generally to a mixture of wet and dry ''deposition'' (deposited material) from the atmosphere containing higher than normal amounts of nitric and sulfuric acids. Wet deposition may be in the form of rain, snow, hail, sleet, fog, dew or frost. Dry deposition consists of gases and solid particles, such as particulate matter or dust, that settle to earth. The term ''pH'' is a measure of acidity or alkalinity ranging from 0-to-14, with 7 considered neutral and anything lower ''acidic.'' According to the U.S. Department of Energy, normal rainfall has a pH of 5.6, which is usually acidic. An exhaustive 10-year study by 1,000 of the nation's foremost scientists (the National Acid Precipitation Assessment Program) concluded that while acid rain has had some impact in certain regions of the United States, it is not an environmental emergency requiring drastic action. The Clean Air Act Amendments strengthened existing requirements and established specific emission targets related to acid rain control.

Assigned. Reserves legally recoverable generally through existing facilities using current mining technology.

Btu-British Thermal Unit. A measure of the energy required to raise the temperature of one pound of water one degree Fahrenheit.

Clean Coal Technologies. A number of innovative, new technologies designed to use coal in a more efficient and cost-effective manner while enhancing environmental protection. The utility and coal industries have spent millions of dollars in clean coal research over the years, but the primary emphasis in the 1980s has been on the federal government's Clean Coal Technology Program. The federal government has awarded over $1 billion in what has been proposed as an eventual $2.6 billion cost-sharing effort with private industry to develop strong technologies, some of which are on the verge of large-scale commercialization. Among the most promising technologies are fluidized-bed combustion, integrated gasification combined cycle, limestone injection multistage burner, enhanced flue gas desulfurization (or ''scrubbing''), coal liquefaction and coal gasification. The Company's Encoal Demonstration Plant in Gillette, Wyoming, was constructed under Round III of the Clean Coal Technology Program Act. See ''Business-Encoal Corporation.''

Coal Seam. Coal deposits occur in layers. Each such layer is called a ''seam.''

Coal Washing. The process of removing impurities, such as ash and sulfur based compounds, from coal.

Coke. A hard, dry carbon substance produced by heating coal to a very high temperature in the absence of air. Coke is used in the manufacture of iron and steel. Its production results in a number of useful byproducts.

Compliance Coal. Coal which, when burned, emits less than 1.2 pounds of sulfur dioxide per million Btu.

Continuous Mining. One of two major underground mining methods now used in the United States (also see ''Longwall'' mining). This process utilizes a machine‹a ''continuous miner''‹that mechanizes the entire coal extraction process. The continuous miner removes or ''cuts'' the coal from the seam, where it simultaneously falls on a conveyor for removal to a shuttle car or larger conveyor belt system.

Deep Mine. An underground coal mine.

Dragline. A large machine used in the surface mining process to remove the overburden, or layers of earth and rock, covering a coal seam. The dragline has a large bucket suspended from the end of a huge boom. The bucket, which is suspended by cables, is able to scoop up great amounts of overburden as it is dragged across the excavation area. These machines, which ''walk'' or move on huge pontoon-like ''feet'', are among the largest land-based machines in the world.

Drift Mine. A coal mine entered directly through a horizontal opening mined into the side of a hill or mountain.

Highwall. Unexcavated face of exposed overburden and coal in a surface mine or in a face or bank on the uphill side of a contour mine excavation.

Longwall Mining. One of two major underground coal mining methods currently in use. Employs a rotating drum, which is pulled mechanically back and forth across a face of coal that is usually several hundred feet long. The loosened coal falls onto a conveyor for removal from the mine. Longwall operations include a hydraulic roof support system that advances as mining proceeds, allowing the roof to fall in a controlled manner in areas already mined. Where it can be used, longwall generally allows the recovery of higher percentages of coal in an efficient manner, at costs that are usually less than those of other underground methods.

Metallurgical Coal. The various grades of coal suitable for carbonization to make coke for steel manufacture. Also known as ''met'' coal, it possesses four important qualities: volatility, which affects coke yield; the level of impurities, which affects coke quality; composition, which affects coke strength; and basic characteristics, which affect coke oven safety. Metallurgical coal has a particularly high Btu, but low ash content.

Overburden. Layers of earth and rock covering a coal seam. In surface mining operations, overburden is removed prior to coal extraction.

Pneumoconiosis Claims. Claims for disability due to a pulmonary disfunction commonly referred to as ''black lung.'' Such claims can be filed pursuant to federal laws or state workers' compensation laws.

Preparation Plant. Usually located on a mine site, although one plant may serve several mines. A preparation plant is a facility for crushing, sizing and washing coal to prepare it for use by a particular customer. The washing process has the added benefit of removing some of the coal's sulfur content.

Probable. A moderate degree of geologic assurance. The assurance, although lower than for measured, is high enough to assume continuity between points of measurement. Coal that lies between 1/4 and 3/4 mile from a point of coal thickness measurement is considered in the indicated class. For certain coal beds in Illinois, coal bed consistency is such that coal between 1/2 mile and 2 miles from a point of thickness measurement is considered in the indicated class.

Proven. The highest degree of geologic assurance. Coal quantities computed from bed thickness measurements in core holes, mine workings and bed outcrops of prospect trenches. The measurement sites are so closely spaced that coal bed continuity, geometry and minability are well established. Generally coal that lies within 1/4 mile of a reliable point of coal thickness measurement is considered in the measured class.

Ranks of Coal. The classification of coal by degree of hardness, moisture and heat content: Anthracite is hard coal, almost pure carbon, used mainly for heating homes. Bituminous Coal is soft, the most common type found in the United States, and is used to generate electricity and to make coke for the steel industry. Subbituminous is a coal with a heating value between bituminous and lignite, and has low fixed carbon and high percentages of volatile matter and moisture. Subbituminous coal is used primarily for generating electricity. Lignite is the softest coal and has the highest moisture content. It is used for generating electricity in certain parts of the country and for conversion into synthetic gas. In terms of Btu or ''heating'' content, anthracite has the highest value, followed by bituminous, subbituminous and lignite.

Reclamation. The restoration of land and environmental values to a mining site after the coal is extracted. Reclamation operations are usually underway where the coal has already been taken from a mine, even as mining operations are taking place elsewhere at the site. The process commonly includes ''recontouring'' or reshaping the land to its approximate original appearance, restoring topsoil and planting native grass and ground covers. Reclamation is closely regulated by both state and federal law.

Recoverable Reserves. The amount of coal that can be recovered from the reserve base. The average recovery factor for underground mines is about 57 percent, and about 80 percent from surface mines. Using these percentages, there are about 300 billion tons of recoverable reserves in the United States, enough to last more than 300 years at current consumption levels.

Roof Bolting. A method of supporting the ceilings of underground mines by inserting long steel bolts into holes bored into the strata forming the roof.

Scrubber. Any of several forms of chemical/physical devices which operate to neutralize sulfur compounds formed during coal combustion. These devices combine the sulfur in gaseous emissions with other chemicals to form inert compounds, such as gypsum, which must then be removed for disposal. Although effective in substantially reducing sulfur from combustion gases, scrubbers require about 6 to 7 percent of a power plant's electrical output and thousands of gallons of water to operate.

Spot Market. Sales of coal pursuant to an agreement for shipments over a period of one year or less. Spot market sales are generally obtained via a competitive bidding process.

Steam Coal. Coal used by power plant and industrial steam boilers to produce electricity or process steam. It generally is lower in Btu content and higher in volatile matter than metallurgical coal.

Sulfur Content. Coal is commonly described by its sulfur content due to the importance of sulfur in environmental regulations. ''Compliance'' coal, when burned, emits no more than 1.2 pounds of sulfur dioxide per million Btu. This term originated as a description of coal as it related to the Clean Air Act. ''Low sulfur'' coal has a variety of definitions but typically is used to describe coals consisting of 1% or less sulfur. A majority of Zeigler's Appalachian and Powder River Basin reserves are of compliance and low sulfur grades.

Surface Mine. A mine in which the coal lies near the surface and can be extracted by removing the covering layer of soil (see ''Overburden''). About 60 percent of total U.S. coal production comes from surface mines. Tons. A ''short'' or net ton is equal to 2,000 pounds. A ''long'' or British ton is 2,240 pounds; a ''metric'' ton is approximately 2,205 pounds. The short ton is the unit of measure referred to in this document.

Unassigned. Reserves legally recoverable using current mining technology, but which require substantial capital investment for facilities to enable recovery of the coal.

Underground Mine. Also known as a ''deep'' mine. Usually located several hundred feet below the earth's surface, an underground mine's coal is removed mechanically and transferred by shuttle car or conveyor to the surface. Most underground mines are located east of the Mississippi River and account for about 40 percent of annual U.S. coal production.

Unit Train. A train of 100 or more cars, carrying only coal. A typical unit train can carry at least 10,000 tons of coal in a single shipment.

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