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See also: term applied to those varieties of See also: coal which do not give off tarry or other See also: hydrocarbon vapours when heated below their point of ignition; or, in other words, which See also: burn with a smokeless and nearly non-luminous flame
.
Other terms having the same meaning are, " See also: stone coal " (not to be confounded with the
See also: German Steinkohle) or "See also: blind coal " in Scotland, and "See also: Kilkenny coal " in See also: Ireland
.
The imperfect See also: anthracite of See also: north See also: Devon, which however is only used as a pigment, is known as See also: calm, the same term being used in See also: geological See also: classification to distinguish the strata in which it is found, and similar strata in the Rhenish See also: hill countries which are known as the
See also: Culm See also: Measures
.
In See also: America, culm is used as an See also: equivalent for waste or slack in anthracite See also: mining
.
Physically, anthracite differs from ordinary bituminous coal by its greater hardness, higher See also: density, 1.3-1.4, and lustre, the latter being often semi-metallic with a somewhat brownish reflection
.
It is also See also: free from included soft or fibrous notches and does not See also: soil the fingers when rubbed
.
Structurally it shows some alteration by the development of secondary divisional planes and fissures so that the See also: original stratification lines are not always easily seen
.
The thermal conductivity is also higher, a lump of anthracite feeling perceptibly colder when held in the warm See also: hand than a similar lump of bituminous coal at the same temperature
.
The chemical composition of some typical anthracites is given in the article COAL
.
Anthracite may be considered to be a transition stage between ordinary bituminous coal and See also: graphite, produced by the more or less See also: complete elimination of the volatile constituents of the former; and it is found most abundantly in areas that have been subjected to considerable See also: earth-movements, such as the flanks of See also: great See also: mountain ranges
.
The largest and most important anthracite region, that of the north-eastern portion of the Pennsylvania coal-See also: field, is a
See also: good example of this; the highly See also: con torted strata of the Appalachian region produce anthracite exclusively, while in the western portion of the same See also: basin on the See also: Ohio and its tributaries, where the strata are undisturbed, free-burning and coking coals, See also: rich in volatile See also: matter, prevail
.
In the same way the anthracite region of See also: South See also: Wales is confined to the contorted portion west of See also: Swansea and See also: Llanelly, the
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CH
central and eastern portions producing steam, coking and See also: house coals
.
Anthracites of newer, See also: tertiary or cretaceous age, are found in the Crow's See also: Nest See also: part of the Rocky Mountains in See also: Canada, and at various points in the See also: Andes in See also: Peru
.
The See also: principal use of anthracite is as a smokeless fuel
.
In the eastern See also: United States, it is largely employed as domestic fuel, usually in close stoves or furnaces, as well as for steam purposes, since, unlike that from South Wales., it does not decrepitate when heated, or at least not to the same extent
.
For proper use, however, it is necessary that the fuel should be supplied in pieces as nearly See also: uniform in See also: size as possible, a condition that has led to the development of the breaker which is so characteristic a feature in See also: American anthracite mining (see COAL)
.
The large coal as raised from the mine is passed through breakers with toothed rolls to reduce the lumps to smaller pieces, which are separated into different sizes by a See also: system of graduated See also: sieves, placed in descending See also: order
.
Each size can be perfectly well burnt alone on an appropriate See also: grate, if kept free from larger or smaller admixtures
.
The See also: common American classification is as follows:
Lump, steamboat, See also: egg and See also: stove coals, the latter in two or three sizes, all three being above 12 in. size on round-hole screens
.
See also: Chestnut below 1i inch above i. inch
.
,r
++ S;'! rr
From the See also: pea size downwards the principal use is for steam purposes
.
In South Wales a less elaborate classification is adopted; but great care is exercised in hand-picking and cleaning the coal from included particles of See also: pyrites in the higher qualities known as best malting coals, which are used for kiln-drying malt and hops
.
Formerly, anthracite was largely used, both in America and South Wales, as blast-See also: furnace fuel for iron smelting, but for this purpose it has been largely superseded by See also: coke in the former country and entirely in the latter
.
An important application has, however, been See also: developed in the extended use of See also: internal combustion See also: motors driven by the so-called "mixed," "poor," " semi-See also: water " or " Dowson See also: gas " produced by the gasification of anthracite with air and a small proportion of steam
.
This is probably the most economical method of obtaining power known; with anSee also: engine as small as 15 See also: horse-power the See also: expenditure of fuel is at the See also: rate of only r lb per horse-power See also: hour, and with larger engines it is proportionately less
.
Large quantities of anthracite for power purposes are now exported from South Wales to See also: France, See also: Switzerland and parts of See also: Germany
.
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