a. Depression in older rock formations in which coal-bearing strata have
been deposited. See also:concealed coalfield; exposed coalfield.
b. A coalfield with a basinal structure; e.g., the Carboniferous Coal
Measures of England. AGI
There are two methods of breaking coal with explosives, namely, blasting
cut coal, which is the method most commonly used, and blasting off the
solid, or grunching. McAdam, 2
a. A building containing the machinery for breaking coal with toothed
rolls, sizing it with sieves, and cleaning it for market.
b. A machine for breaking coal.
Coal made more suitable for burning by a process that forms it into a
regular square- or oval-shaped piece. Bennett
See:briquette
Sudden outburst of coal and rock that occurs when stresses in a coal
pillar, left for support in underground workings, cause the pillar to
rupture without warning, sending coal and rock flying with explosive
force.
An appliance for loosening coal by means of high-pressure water and oil.
It consists of a round, stainless steel bar with small telescopic rams
acting on a steel liner in a shot hole. The bar is connected to a hand- or
power-operated pump placed near the face. The high-pressure liquid from
the pump causes the rams and liner to exert a pressure sufficient to
loosen or break down the coal. It is a safe method of coal breaking
without the use of explosives. It has not, however, made the progress
originally anticipated. See also:water infusion
Syn:hydraulic cartridge
A car used in hauling coal in or from a mine. Craigie
A cart for carrying coal. Craigie
A trough or spout down which coal slides from a bin or pocket to a
locomotive tender, or to vessels, carts, or cars. Fay
A piece of land having, or thought to have, valuable coal deposits on it
and legally claimed by one seeking to own it. Mathews
The grouping of coals according to certain qualities or properties, such
as coal type, rank, carbon-hydrogen ratio, and volatile matter.
See also:high-volatile coals
One system classifies coal by the content of volatile matter: with 10%
volatile, anthracite; between 10% and 13% lean coal, semianthracite or
dry-steam coal; 14% to 20%, variously designated; 20% to 30%, fat or
coking coal. Other systems classify by calorific value, and caking and/or
coking property. Post-World War II classifications include (1) volatile
matter, (2) caking properties on rapid heating, and (3) coking properties.
See also:ASTM coal classification
Clay found under a coalbed, usually a fireclay. See also:underclay
The sorting, picking, screening, washing, pneumatic separation, and mixing
of coal sizes for the market.
Equipment used to remove impurities -- such as slate, sulfur, pyrite,
shale, fire clay, gravel, and bone -- from coal.
A plant where raw or run-of-mine coal is washed, graded, and treated to
remove impurities and to reduce ash content. Syn:washery
Pryor, 3
The loading of broken coal at the face into conveyors or mine cars. The
clearing shift is the coal-loading shift or stint. Usually the miner has a
measured task or stint (stent). Nelson; Pryor, 3
A conglomerate made of fragments of coal. Tomkeieff
coal constituent classification
In the United States it is generally agreed that the maceral concept of
the nomenclature Stopes-Heerlen System fails to comprehend the effect of
the stage of coalification on the nature of coal constituents. W.
Spackman's interpretation of the maceral concept incorporates the ideas of
variable coalification in suggesting a skeletal framework upon which a
systematic classification can be built. The maceral concept, as
interpreted by Spackman, implements the classification of the products of
coalification. In this scheme, macerals possessing similar chemical and
physical properties are assembled into maceral groups that can, in turn,
be characterized by a comparatively restricted set of properties. Maceral
groups possessing similar characteristics can be classified into maceral
suites. Syn:Spackman system
a. The longwall coal cutter is a power-operated machine that draws itself
by rope haulage along the face, usually cutting out a thin strip of coal
from the bottom of the seam, in preparation for shot firing and loading or
a cutter loader. The bar and disk machines are obsolescent and the chain
coal cutter is now almost universal. Nelson
b. See:machineman