Coal bin

“ In drawing off the washed coal, or when the uncrushed raw coal is to be drawn from a bin and crushed for the washing tests, however, a gate just below the coal-flow regulating gate is thrown in, and the coal falls into a central hopper instead of into the sluice box. Ordinarily, this gate forms one side of the vertical chute. The coal in this central hopper is carried by a chute to the apron conveyor, and thence to the roll disintegrator, or, in case it is washed coal, to a swing-hammer crusher. ”

“ At the beginning of the present century the anthracite or stone coal was in general use, in all the districts where it was found, as a fuel for the blacksmith’s fire and the iron worker’s forge. This, however, was the limit of its utility. It was thought to be necessary to force a strong artificial air current up through it to make it burn, and since this could not well be done in grates, stoves, or furnaces, there was no demand for coal for domestic use, or for the great manufacturing industries. ”

“ To the poor people who live in the vicinity of the breakers these heaps of refuse coal are an unmixed blessing. Pieces of good coal are always being thrown out inadvertently with the waste, and the bony coal that is discarded is not by any means without value as a fuel; indeed it makes a very respectable fire. So, too, one can obtain, with a screen, from the culm heap quite a little percentage of material that will burn. ”

“ The first cause is probably the most important, and this is particularly true of anthracite coals where a sliding scale of prices is used according to the season of the year. While market conditions serve as one of the principal reasons for coal storage, most power plants and manufacturing plants feel compelled to protect their coal supply from the danger of strikes, car shortages and the like, and it is customary for large power plants, railroads and coal companies themselves, to store bituminous coal. ”

“ In rich fields, there are from three to ten of these rich layers or beds of coal, one above another. It often happens that the thickest and best layer is the lowest, and when this is the case, it is usually mined first, regardless of the fact that some, and possibly all, of the higher beds are dislocated and broken or filled with deadly gases. Nearly all this loss could be avoided by simply mining the upper stratum first. ”

“ Other statistics collected by the Geological Survey show that, to the close of 1907, nearly 7,000,000,000 tons of coal had been mined in the United States, and it is estimated that for every ton mined nearly a ton has been wasted, 3,500,000,000 tons being left in the ground or thrown on the dump as of a grade too low for commercial use. ”

“ But with the revival of business, mining was again begun in the Richmond field, and from 1874 to the present time the industry has prospered and grown, and Virginia has furnished to the country at large a considerable amount of an excellent quality of bituminous [40] coal. This coal bed covers an area of about 180 square miles, and has an average thickness of twenty-four feet. It is supposed to contain about 50,000,000 of tons yet unmined.
Another of the early discoveries of coal in the United States was that of the Rhode Island anthracite bed in 1760. ”

“ It occurs in the greatest quantities in the coal mines of the counties of Northumberland, Durham, Cumberland, Staffordshire, and Shropshire. It is more abundant in coals of the caking kind, with a bright steel-grained fracture, than in cubic coals of an open-burning quality. Splint coals are still less liable to disengage this gas. In some extensive coal-fields it exists copiously on one range of the line of bearing, while on the other range, none of it is observed, but abundance of carbonic acid gas. ”

“ In the great coal-field of South Wales, to which we must look for our main supply of anthracite, we are able to trace the action of heat in producing a whole series of different classes of coal in a single seam, which at one part is highly bituminous—soft, flaming coal, like the Wallsend, then it becomes harder and less bituminous, then semi-bituminous “steam coal,” then less and less flaming, until at last we have the hard, shiny form of purely carbonaceous coal, that may be handled without soiling the fingers, and which burns without flame, like coke or charcoal. ”

“ Taking the coal measures of South Wales and Monmouthshire, we have a series of accumulations in which the coal-beds become not only more anthracitic toward the west, but also exhibit this change in a plane which may be considered as dipping south-south-east, at a moderate angle, the amount of which is not yet clearly ascertained, so that in the natural sections afforded, we have bituminous coals in the high grounds and anthracite coals beneath. ”

“ The carboniferous measures are the highest and latest geological formation in the great coal fields of the United States. Therefore where the strata have not been disturbed by flexure the coal seams lie near the surface. This is generally the case in the bituminous districts, and it is also partially true in the northern anthracite coal field. Deep mining is necessary only in the middle and southern anthracite coal fields, where the folds are close and precipitous, and the deep and narrow basins formed by them have been filled with deposits of a later geologic age. ”

“ This is employed in 157cases where intense heat is requisite, as for the smelting of iron ore; and likewise where acid and bituminous particles of coal would be detrimental, as in the drying of malt.
What is usually termed culm is the refuse or dusty coal, produced in working the common coals. It contains much earthy matter, will not kindle in an ordinary fire-place, but produces considerable heat and flame in a furnace, where a strong current of air is introduced. In England it is exempted from the high duty imposed on other coals, and is sold at a very low price. ”

“ It is their duty to pick out the pieces of slate, stone, or bone, from the stream of coal which passes under them, and throw this refuse into a trough at the side of the shute, from which point it slides rapidly away. The coal as it comes from the mine is full of waste material, so that the boy who sits first or highest on the shute has no trouble in finding plenty to do, and, work as hard as he may, much of the unfit material must still escape him. ”

“ This is an example of wholly useless waste of coal, and just such waste is to be found in hundreds of places in our country.
If wise mining methods be put into operation, if proper care be taken in its use, particularly in manufacturing, if the low-grade coals be utilized, and if other power be substituted wherever practicable, [Pg 143] there need be no question of shortage. There is enough coal in the ground, if used rightly, to last for ages to come. ”

“ The most modern mines use fewer supporting pillars of coal, and these are of larger size, so that there is less danger of accidents. Wherever possible they use timbers of wood instead of these smaller pillars of coal. They also mine as near the top of the seam of coal as can be done safely, and so regulate the blasting that much less slack is made than by the heavy discharges. These changes in mining methods save a far larger proportion of coal, and also prevent many accidents, which are the most unfortunate feature of coal mining, and the one which should receive most careful consideration. ”

“ From the point of view of national economy the better utilization of what are known as the by-product values of bituminous coal is quite as important as the establishment of an integrated power system.
For coal is much more than potential power. Bituminous coal is the source of many of our most valuable mineral products and yet today, of the more than 500,000,000 tons annually produced, almost all is used exclusively for the production of power and all of its ingredients except the heat-producing elements are wasted. ”

“ The elimination of smoke means more complete combustion of the fuel, and consequently less waste and higher efficiency.
The investigations into the waste of coal in mining have shown the enormous extent of this waste, aggregating probably from 300,000,000 to 400,000,000 tons yearly, of which at least one-half might be saved. It is being demonstrated that the low-grade coals, high in sulphur and ash, now left underground, can be used economically in the gas producer for power and light, and, therefore, should be mined at the same time that the high-grade coal is being removed. ”

“ Several of the poorest grades of bituminous coals have shown remarkable efficiency in the gas producer, and lignites and peat have been used with great facility, thus opening the way to the introduction of cheap power into large districts that have thus far been commercially unimportant owing to lack of industrial opportunities. Experiments with “bone,” a refuse product in bituminous-coal mining, have given excellent results, showing an efficiency in the producer equal to that reached by good steam coal under boilers. ”

“ Where the coal is thickest, no less than 10 bands of it are worked in this way, as is shown in fig. 849. When any band of the coal is foul from sulphur or other causes, it is left for the next platform, so that a large proportion of it is lost, as in the Staffordshire mines. Much attention must here be paid to the vertical distribution of the pillars and apartments; the miner’s compass must be continually consulted, and bore-holes must be put down through the coal scaffoldings, to regulate correctly the position of the pillars under one another. ”

“ Central heating and power plants that can burn coal efficiently will no doubt be more popular and numerous in a few years. Government control and legislation may be expected to hasten the changes. In Europe the technique of coal mining, except in undercutting machinery, is further advanced than in the United States, as regards mining all the coal and in supporting the surface. ”

“ Not a few coal fields have already been exhausted, as in portions of Iowa and Missouri. Yet, in the face of these known facts, we continue to treat our coal as though there could never be an end of it. The established coal-mining practice at the present date does not take out more than one-half the coal, leaving the less easily mined or lower grade material to be made permanently inaccessible by the caving in of the abandoned workings. ”

“ That is, they were all bituminous; but during the violent contortions and upheavals of the earth’s crust at the time of the Appalachian revolution at the close of the Carboniferous age, the bituminous coals involved in that disturbance were changed by heat, pressure, [13] and motion, and the consequent expulsion of volatile matter, from bituminous to anthracite.
Cannel coal is a variety of bituminous coal, burning with great freedom, the flame of which affords considerable light. ”

“ The experience of domestic buyers of coal would seem to indicate, either that the picker boys do not do their whole duty or that the picking [189] machines have not yet been made perfect. But it must be remembered that the separation of slate and bony coal from good material is made only in a rough and general way in the mine, and that a very large percentage of the output, as it reaches the breaker, is unfit for use. To clean and separate this material thoroughly, therefore, requires much labor, and extreme care and skill. ”

“ Hard coal of good quality has 90 per cent or more of carbon, and burns with little flame. Soft coal contains as much as 18 per cent of flame-making substances, and gives off a heavy smoke. Hard coal is therefore cleaner, but it is more costly than soft coal, because the supply is smaller. The most important anthracite mines are found in the eastern United States, and hard coal is used more in this section than elsewhere. Good hard coal may be recognized by its glossy black color and bright surfaces. It is sold under different names taken often from the locality where it is mined. ”

“ It must not be thought that in this huge area the coal is all uniformly good. It varies greatly in quality, and in some districts it occurs in such thin seams as to be worthless, except as fuel for consumption by the actual coal-getters. There are, too, areas of many square miles in extent, where there are now no coals at all, the formation having been denuded right down to the palaeozoic back-bone of the country. ”

“ Detailed reports of the coal-basin give not less than seventy-five thousand acres of coal-bearing land, estimated to produce from the one vein at present worked not less than four hundred and fifty million tons of coal. As many as six workable seams are, however, known to exist, including one which has been prospected to eleven feet in thickness. Five coal-mines have been opened, which are capable of producing about two thousand tons of coal daily. ”

“ At Whitehaven, the principal entrance to the coalmine, both for men and horses, is by an opening at the bottom of a hill, through a long passage hewn in a rock. This, by a steep descent, leads to the lowest bed of coal. The greatest part of the descent is through spacious galleries, which intersect other galleries; all the coal having been cut away, except large pillars, which, in deep parts of the mine, are three yards high, and about twelve yards square at the base, such great strength being there required to support the ponderous roof. ”