Brown coal

“ Where thirty or forty seams of coal have been found one below another, we have evidence of land and water thus changing places many times.
When vegetable matter is excluded from air and under great pressure, it decomposes slowly, parting with carbonic acid gas; and is first changed into lignite or brown coal, and then into bituminous coal, or the soft coal that burns with smoke and flame. I have been in a coal-mine where the carbonic acid gas, pouring from a crevice in the coal, put out a lighted candle. ”

“ If bituminous coal, it contains also a certain amount of hydrogen, which in combination with carbon enables it to yield gas and coal tar, and which causes it to burn with flame. If, again, we examine some of the more imperfect and more recent coals, the brown coals, so called, we shall find that in composition and texture they are intermediate between coal proper and hardened or compressed peat. ”

“ Lignite is the name which has been applied to a form of impure coal, which sometimes goes under the name of "brown coal." It is not a true coal, and is a very long way from that final stage to which it must attain ere it takes rank with the most valuable of earth's products. From the very commencement, an action has being going on which has caused the amount of the gaseous constituents to become less and less, and which has consequently caused the carbon remaining behind to occupy an increasingly large proportion of the whole mass. ”

“ The productive coal-fields of the United Kingdom belong to the Carboniferous period; brown coal of Jurassic or Tertiary age is known to occur, but the seams are too small to be profitably exploited. The exports of coal from this country are of great importance, amounting in 1900 to 51,638,000 short tons, valued at $193,032,000. Much of the coal goes to Italy, Russia, Holland, and to the European countries that possess small resources of the mineral, while the remainder is exported to the more remote parts of the world. ”

“ He saw new cities, new docks; a good day's work yet to be done, and many vast undertakings only just begun, The coal, the iron and the gold, are ours; we have noble days in store, but we must labor more than we have yet one. ”

“ Peat is present in innumerable swamps throughout the humid, temperate portion of the continent, especially from Louisiana and Florida northward, to the region about the Great Lakes and widely throughout Canada, but is at present of small commercial importance, although steps are being taken for its extensive utilization.
The most valuable of the coal deposits are of Carboniferous age, and lie to the east of the Rocky Mountains. The most of the coal is bituminous, or soft coal, used principally in generating steam and for manufacturing gas and coke. ”

“ 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. ”

“ 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. ”

“ 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. ”

“ Thus the freedom of burning increases with the amount of volatile hydrocarbons, while the heating power depends on the amount of fixed carbon present. Sulphur is an injurious constituent when the coal is to be used in the manufacture of gas or for metallurgical purposes; while ash is undesirable, since it displaces so much carbon, and if it contains fusible impurities such as iron, lime, or alkalies, it causes clinkering. Moisture retards the heating power of the coal until it is driven off. ”

“ With this immense stock of fuel in the cellars of the earth, it seems evident that we need not trouble our minds or be anxious as to the duration of our coal supply. Besides, the conversion of vegetable matter into coal seems to be going on even now. In the United States there are peat-bogs of considerable extent, in which a substance exactly resembling cannel coal has been found; and in some of the Irish peat-beds, as also in the North of Scotland, a similar substance has been discovered, of a very inflammable nature, resembling coal. ”

“ 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. ”

“ One of the greatest single causes of waste and increased prices is our antiquated system of distributing the energy contained in coal. It is estimated that every hundred tons of coal shipped involves the burning of ten tons in railroad locomotives. There is no longer any technical justification for transporting power in the enormously bulky form of coal when it could be much more efficiently distributed by pipe and wire in the form of gas and electricity. ”

“ Moreover, wherever heat rather than light or power is desired, gas, in the present state of technical development, is even more economical than electricity. Under the by-product system the present annual coal output can be made to more than double its service in driving machinery and in addition it can be made to contribute heavily to our supply of fertilizers, motor fuel, and chemical [Pg 98] products. It is estimated that the aggregate loss resulting from the present wasteful utilization of coal is over ten dollars a year for each inhabitant of the United States. ”

“ 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. ”

“ Mineral coal, however, having been buried in water, mud, and sand, must, almost of necessity, have some mixture of foreign matter, either slate, which is simply hardened mud; silica, which may have been derived from sand; iron and sulphur, some [Pg 101] of which may have been in the wood, but most of it, probably, introduced in solutions; to which should be added, unexpelled oxygen, which is not only useless as fuel, but which combines with a portion of the contained hydrogen, and forms water in the substance of the coal. ”

“ 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 presence of more than 1% of sulphur renders coal unfit for the economical production of good light-gas, and more than 2% of sulphur renders it objectionable for use as domestic fuel. In like manner, coals containing mineral ingredients in excess are to be avoided, not merely on account of the quantity of ashes left by them, but for their tendency to vitrify upon the bars of the furnace, and to produce what is technically called ‘clinkers.’ The presence of much silica or alumina, and more particularly of any of the salts of lime, in ‘steam coal,’ is, on this account, highly objectionable. ”

“ 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 may indeed be hard to see how a practical method for drawing on this vast reserve of heat can be devised, but it is at least conceivable that it may be rendered available when the coal and other more accessible sources have become exhausted, or even when their yield has considerably lessened.
The coal of England may last a century or two; the coal in other parts of the globe may supply our cellars for a few centuries more, but the exhaustion of this truly marvellous product is proceeding at an accelerated pace. ”

“ About two-fifths of the world's annual output is mined in the United States.
The very abundance of the supply has made us enormously wasteful in its exploitation, as we have been wasteful in the exploitation of our forests. Unlike the forests, coal once destroyed does not grow again. The most valuable of our coals are in the Appalachian bituminous fields that stretch from northern Pennsylvania to Alabama, and in which some of the best sections have already been gutted and abandoned. ”

“ Thus all this abundant wealth of money and of vivid life is Nature’s investment in club-mosses and the like so long ago. But what becomes of the coal which is burnt in yielding the interest? Heat comes out of it, light comes out of it, and if we could gather together all that goes up the chimney and all that remains in the grate of a thoroughly-burnt coal fire, we should find ourselves in possession of a quantity of carbonic acid, water, ammonia, and mineral matters, exactly equal in weight to the coal. ”

“ Two-thirds of the coal mined in the United States is obtained from the Appalachian field, extending from New York to Alabama, Pennsylvania being the largest coal-producing state in the Union. In the iron and steel industries [Pg 23] most of the coal is coked, as it is better for blast-furnace use in this form, giving greater heat and containing less sulphur or other injurious substances than coal. ”

“ A long interment followed, during which a course of chemical changes, and new combinations of their vegetable elements, converted them to the mineral condition of coal. By the elevating force of subterranean agency, these beds of coal have been uplifted from beneath the waters, to a new position in the hills and mountains, where they are accessible to the industry of man. From this fourth stage, coal has been removed by the labours of the miner, assisted by the arts and sciences, that have co-operated to produce the steam-engine, and the safety-lamp. ”

“ So it is that by hard work and much danger we get coal for burning. Now, coal is dirty and heavy. A coal fire is hard to kindle and hard to put out, and the ashes are decidedly disagreeable to handle. And after all, we do not really burn the coal itself, but only the gas from it which results from the union of carbon and oxygen. In some places natural gas, as it is called, which comes directly from some storehouse in the ground, is used in stoves and furnaces and fireplaces for both heating and cooking ”

“ 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. ”

“ The soft coals, on the contrary, being porous as well as soft, allow the gases to escape from them much more readily, and so increase the danger at the working faces of the mines. The gas given out most abundantly by the coal is light carbureted hydrogen, known as marsh gas, from the fact that being a product of vegetable decomposition under water, bubbles of it rise to the surface on stirring the waters of a marsh. This is the gas that is known to miners as fire damp. ”