ESSAY III

SUBTERRANEAN TREASURES-COAL, IRON, &c.

FIVE hundred and fifty million tons is a quantity that is almost inconceivable to the human mind, and yet it approximately represents the amount of coal that was dug out of the earth and converted into smoke and ashes in the course of a single year. Of this vast total Great Britain is responsible for nearly one-third, or, to be precise, 189,652,562 tons in the year 1895. With this production our country far outstrips all others. Even the United States are twenty-five million tons behind; but they hope to surpass us very shortly, and in this expectation they are justified, considering their area and their rapidly increasing population and manufactures. The present state of trade in this country, and of the civilisation which is based upon it, may be said to depend on three things-our men, our ships, and our coal. These in their turn represent our cumulative progress from the early times, from the Middle Ages, and from the beginning of the present century. Upon fuel all our manufactures now depend, for there is scarcely a single industry that can dispense with heat and steam-power, so that we should indeed be in a pitiable plight if the output were reduced to the ten million tons that were produced in 1800. A scuttleful of that size would not even satisfy domestic demand at the present day. Even the respectable total of a hundred million tons was not sufficient thirty years ago, when the enormous growth so alarmed the country that a Royal Commission was appointed to investigate, inter alia, the probable duration of the coalsupply. The data for such a calculation were necessarily so speculative that no absolute period could be named, but it may safely be said that another two or three centuries are well assured not only against cold, but also against loss of power.

Whilst the production has thus developed, the labour employed has similarly increased, but naturally not at the same rate, owing to the wider introduction of machinery. Trustworthy statistics for the beginning of the century are not to be

obtained, but it is estimated that 50,000 work people were employed to raise the ten million tons.

Now, according to Her Majesty's Inspectors of Mines, there are employed in mines under the Coal-Mines Act no less than 700,284 work people, of whom about 80 per cent.-564,638— are underground workers. Not quite all these are engaged in coal-mining, as the Act covers mines from which about eleven million tons of other materials, such as fireclay, oil-shale, and iron ore, are obtained, in addition to the coal-mines, yielding 189 million tons of coal. Taking these proportions, it will be seen that the output of coal has increased nineteen times, and the number of labourers somewhere about thirteen times. The advance of the labourer himself cannot be estimated in figures, but it has been enormous, as the following pages will show.

Strange as it may seem, it was not until 1799 that slavery was finally abolished in this country, but in that year an Act was passed freeing the Scottish colliers from their state of serfdom. Some of their disabilities had been removed about forty years before, but they were always regarded as the lowest of the low-as pariahs, in fact not only in Scotland, but also in England. South of the Tweed they had never received much attention from the Legislature, but rather they suffered from its neglect; and even at the beginning of this century they were omitted from the benefits conferred upon factory labour by several Acts of the time. Popular attention was, however, being strongly attracted to the condition of the mining classes by the increasing frequency of disastrous fire-damp explosions, and the first and greatest advance of the century for the collier was made in the discovery of the safety-lamp in 1815.

Prior to that date the miner had to work with a naked light as long as he dared, or else to use the inefficient illumination of sparks given off by revolving a steel wheel against a flint. The ventilation of the mines, although constantly being improved, was not sufficient to thoroughly remove the gas when the seam produced it in quantity, and so it was a general practice to fire the gas in the mine. For this For this purpose, before the men went into the pit, one man, dressed in heavy water-sodden clothes, would crawl up to the dangerous places and set light to the gas with a candle mounted on a long stick or on a board which he pulled along with a string. Sometimes this had to be done several times a day. It was very evident that lights had to be protected, and the problem was successfully and simultaneously solved by two independent inventors, Sir Humphry Davy and George Stephenson. Great as the invention was, the fame of neither rests entirely upon it, for Stephenson was the father of railways, and Davy, central figure

of the illustrious trio comprising Rumford and Faraday, was the discoverer of sodium, potassium, aluminium, and many another item of our chemical knowledge. Stephenson found that the flame from a mixture of fire-damp and air would not pass through narrow tubes, and Davy found that wire-gauze served the same purpose. Wire-gauze is now universally adopted, but useful lamps were made on both principles.

The joy with which this invention was received can better be imagined than described, and many thought that explosions were a thing of the past, but a very few years showed that these catastrophes were more numerous and much more disastrous than before. This, however, was easily explained. Coal-mining was growing vigorously, workings were being greatly extended, and more especially the speed of ventilating currents was largely increased. In stronger draughts the lamp, as originally constructed, is not safe, since it allows the flame to pass through the gauze, and to obviate this many improvements were, and are still being, made. Finality has not been attained, yet there is probably no great room for improvement. If anything more is to be done, it is only to slightly increase the safety and the light-giving power of the lamps, of which there are so many varieties on the market. Safety-lamps will most likely be displaced in the near future by portable electric lamps, of which many good ones are already in use. The probability of an explosion through the exposure of the incandescent filament by the breakage of a bulb is very remote, and may easily be guarded against. At the present time the weight and expense of these lamps are their most objectionable features.

Until recent years coal dust was not recognised as a possible cause of explosion, but it is now well appreciated that many kinds of dust, when they are in a fine state of division and suspended in the air, will propagate flame with explosive violence, especially when a small percentage of gas is present. The tendency is now to ascribe all explosions to dust rather than to gas, but the primary cause of an explosion at the present time is not the lamp, but the flame from blasting operations. As far as the dust itself is concerned, the main precautions now taken are to thoroughly damp the dust, so as to cause it to settle and become inert. In all probability some legislation on this matter may be looked for at an early date, and precautionary measures will be enforced where dangerous. dusts occur, in the same way that the use of safety-lamps is compulsory when fire-damp is present.

Explosions naturally attract more attention than other sources of danger, because many lives are so often involved in

one catastrophe, but, as a matter of fact, they are only accountable for about fourteen per cent. of the total fatalities during the last decade. A far more fertile source of accident is to be found in falls of rock, due often to the treacherousness of the roof or strata over the coal-seam. During the last decade this was accountable for no less than forty-four per cent. of the deaths. Nothing will prevent this danger but constant vigilance and strict attention to the timbering in the mine. Division of labour, whereby special men are told off to attend to the timbering and the underground roads, has doubtless improved the condition of affairs.

The ventilation of mines has already been referred to, but it may be added that practically all the improvements are due to the present century. In its early part this subject attracted attention to the exclusion of most other details, but it may be said that 1860-1870 saw the introduction, on a considerable scale, of the fan, which is now almost the only admissible way of passing air through a colliery. At one time furnaces were used, if indeed natural ventilation was not trusted to, but now they have mostly disappeared. The present tendency is to revert to smaller-sized fans, but they are run at very much higher velocities, so as to pass the requisite quantity of air. Authorities differ as to what should be allowed, but it is often taken that 100 cubic feet of air per minute should be passed through the mine for each man, and 600 cubic feet for a horse. More air is, of course, required where much gas is evolved; but the men are not likely to be choked with bad air as long as this quantity can be kept in circulation.

Now let us turn to the more mechanical side of mining, to the means for getting the coal and for facilitating the men's work, whereby the enormous outputs of the present day are obtained. The coal itself occurs as a layer or bed, which may be only a few inches in thickness, or it may be as much as thirty feet, as in the South Staffordshire thick seam. Coal thinner than fifteen inches is not much worked, as it does not pay to extract the adjacent worthless material to make room for the roads. The most arduous part of the coal-miner's occupation consists in undercutting the coal-that is, in extracting part of the coal, so that the rest will fall down. To do this, the miner lies partly on one side, with one leg drawn up under him, and picks away with a light pick, weighing about 2 to 2 lbs., and having a handle some 24 to 30 inches long. As near to him as possible is placed a safety-lamp, which gives about as much light as a very ordinary candle. The constrained position and inefficient light do not conduce to efficient work.

The substitution of machinery for hand-labour of this kind has absorbed the attention of many inventors during the last fifty years, and there have been very numerous forms of machines put on the market. An early type of machine resembled the miner in its action, as it had a swinging pick, but this form is mostly abandoned in favour of those machines which have an endless chain, or a wheel, or a revolving bar, carrying cutter teeth to scrape away the coal. There are, however, two other types which have found an extended use. In one a reciprocating chisel, very much like a rock-drill, is used, and in the other a revolving borer cuts an annular groove, and the projecting core is then extracted to leave a circular tunnel or road.

It would be invidious to compare these machines, as any and all of them are capable of doing good work when they are properly constructed and used. In order to give satisfaction the machine must be light, and small enough to be managed by two or three men working generally in a confined position. It must be strong, so as not to be injured by any falls from the roof of the coal-seam. It should be able to start operations without any manual preparation, and it must have plenty of power, so as to cut through obstructions or patches of hard

materials that are so often encountered.

In this country these machines have as yet found only a limited use, although their employment is extending fairly rapidly. This has been more especially the case since electric transmission of power has come so deservedly into fashion, for it offers exceptional facilities to the use of these machines. They have to be moved very frequently, and the trouble of altering the power connections is limited to changing the position of a few yards of insulated wire. Good work has been and will be done with compressed air, but it is far more troublesome to constantly alter the position of pipes. Steamengines attached to the machines, it need hardly be remarked, are quite out of the question.

The actual saving is a very variable quantity, depending on so many circumstances. Mr. G. Blake Walker, for instance, mentions a seam three feet in thickness, where hand labour made 25 per cent. of slack, or small coal, as compared with 15 per cent. by machines, and the saving amounted from 8d. to is. 6d per ton, of which two-thirds resulted from the larger proportion of lump coal.

When the coal is undercut as far as is considered advisable for reasons of economy or safety, the props are withdrawn. In some mines the coal will fall without further aid, or it may be brought down with a slight expenditure of force applied by