The Subterranean World

by G. Hartwig

DUDLEY COAL-FIELD.
1. Limestone strata. 2. Coal.

Of the smaller coal-fields, the most important are the Whitehaven basin (one hundred and twenty square miles) and the Dudley or South Staffordshire area (ninety square miles) which is particularly valuable for the extensive iron works which it maintains. One portion of this coal-field is distinguished by the presence of one continuous bed of coal thirty feet thick, which for British coal is astonishing; and this mass extends seven miles in length and four in breadth. In this favoured district coal-seams five or six feet thick are called thin seams; in Newcastle they would be called thick seams.

Though not so extensive as the South Welsh area, the coal-fields of Newcastle and Durham are of far more ancient celebrity. Their produce is chiefly shipped on the Tyne, Wear, and Tees, small rivers hardly traceable on a map of the world, and yet far more important to commerce than the mighty Orinoco or the thousand-armed Amazon. This magnificent coal area is bounded on the north by the river Coquet, and extends southward nearly as far as Hartlepool, a distance of about forty-eight miles. Its extreme breadth is about twenty-four miles, and the whole superficial extent may amount to about eight hundred square miles.

There are in all about fifty-seven different seams of coal in the Great Northern Coal-field, varying in thickness from an inch to five feet five inches and six feet, and comprising an aggregate of about seventy-six feet of coal.

The pits are established chiefly with reference to one or more of the three following seams. The most valuable is called the High Main Seam, and is about six feet thick. The next in value is the Bensham Seam, about three feet thick, which is remarkable for its excellent quality as a domestic coal, and for the enormous quantity of gas evolved from it in the mine. The Hutton or Low Main Seam, averaging from three feet six inches to five feet nine inches, is likewise of very good quality, and is extensively worked. It must, however, be remarked that the same seam of coal is not generally valuable in all places. Thus the High Main, which furnishes excellent coal on the Tyne, becomes injured as it proceeds in a south-easterly direction by being intermixed with a band of coal of inferior quality containing iron pyrites, &c.

The Newcastle Coal-field is generally worked at a great depth, an expense of upwards of 50,000l. having in some instances been incurred before the seam of coal was reached which was to reward all this vast outlay and labour. The most remarkable and enterprising work of this kind on record is a sinking at Monk Wearmouth Colliery near Sunderland. After piercing the superincumbent beds of magnesian limestone and lower new red sandstone, the coal strata were reached at a depth of three hundred and thirty feet; but at the same time a spring was tapped which poured water into the workings at the rate of three thousand gallons per minute. This fearful influx was kept under by a steam-engine of two hundred horse-power, and the work was made sure by strong metal tubbing, and carried on successfully, though not without extreme difficulty. On entering the coal measures, however, a new and unexpected check was experienced in the extra thickness of the uppermost coal strata, for which no calculation had been made, and the difficulties were increased when at the depth of one thousand feet a fresh feeder or spring of water was tapped. Additional expense and great loss of time were thus caused; but the proprietors persevered with real Anglo-Saxon pertinacity, undaunted by the apparently hopeless nature of the undertaking, and by the fearful expenses incurred. Success crowned their efforts, and finally, at a depth of 1,710 feet, the Hutton seam of coal was reached, at a cost which, including the necessary preliminary operations, could not have been less than 100,000l.

Another remarkable and costly piece of mining was that of Gosforth Colliery, which lies about three miles north from Newcastle, on the west bank of a romantic ‘dean’ or little valley, through which the Ouseburn winds its way to the Tyne. The sinking was commenced in 1825, and the coal was won on Saturday, January 31, 1829. The High Main coal was reached at twenty-five fathoms below the surface, but near its first appearance the seam was thrown down in an inclined direction by the great Ninety Fathom Dyke which there intersects the coal-field. Hence it became necessary to sink the shaft to the depth of 181 fathoms, in order to come at the level of the lower range of coal. This having been accomplished, a horizontal drift 700 yards long was worked through the face of the dyke to the seam of coal a little above its junction with the dyke. A great part of this excavation had to be made through solid rock. To celebrate the completion of this remarkable work, a grand subterranean ball was given at the very place of triumph, 1,100 feet below the surface of the earth. As the guests arrived at the bottom of the shaft they went to the end of the drift to the face of the coal, where each person hewed a piece of coal as a memento of the day, and then returned to the ball-room, which was brilliantly lit up, and where born-and-bred ladies joined in a general dance with born-and-bred pitmen’s daughters. Between 200 and 300 persons were present, nearly one-half of them belonging to the fair sex. It must be remembered that the pit had not been worked, so that no smoke and dust exuded from its mouth or defiled the ball-room.

Some of the older coal-pits, where excavations have been going on perhaps for a century or more, may be likened to large subterranean cities. The galleries of St. Hilda Colliery, near South Shields, are full seventy miles long; and Killingworth pits are said, on good authority, to have nearly one hundred and sixty miles of gallery excavation.

In some parts the operations of the collier have encroached upon the domains of the ocean. At the Howgill pits, for instance, west of Whitehaven, the excavations have been carried more than 1,000 yards under the sea, and about 600 feet below its bottom. But the most remarkable marine colliery which Great Britain has ever possessed was situated at Borrowstounness. The coal was found to continue under the bed of the sea in this place, and the colliers had the courage to work it half a mile from the shore, where there was an entry that went down into the submarine coal-pit. This was made into a kind of round quay, built so as to keep out the tide which flowed there twelve feet. Here the coals were laid, and a ship of that draught of water could lay her side to the quay and take in the coal. This wonderful pit, which belonged to the Earl of Kincardine’s family, continued to be wrought many years to the great profit of the owners, and the astonishment of all that saw it; but at last an unexpected high tide drowned the whole at once, together with the labourers who were at work. ‘While,’ says the French geologist, Faujas de Saint Fond (who visited this remarkable mine about the end of the last century), ‘the pitmen, by the dismal shine of their lamps, make the deep caverns resound with the blows of their pickaxes, ships driven by a fair wind sail over their heads, and the sailors, rejoicing at the beautiful weather, express their joy in songs: at another time a storm arises; the horizon is in flames, the thunder roars, the sea rages, the boldest tremble; then the pitmen, unconscious of the terrible scene, calmly pursue their labours, and think with pleasure of their homes, while the ship above is shattered to pieces and sinks; unfortunately, but too faithful a picture of the daily changes of human life.’