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 machinea ''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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