After a time the thin snake begins to ascend; they are coming up now, but not so fast as they went down. It is about ten minutes before the gig emerges from that black hole and bears the Prince and Princess once more into the light of day.
Yes, it was a great day for Botallack, and it will dwell long in the memories of those who witnessed it—especially of that fortunate captain of the mine who had the honour of conducting the Princess on the occasion, and of whose enthusiasm in recalling the event, and in commenting on her intelligence and condescension, we can speak from personal observation.
But, reader, you will say, What has all this to do with our story?
Nothing—we admit it frankly—nothing whatever in a direct way; nevertheless, indirectly, the narrative may possibly arouse in you greater interest in the mine down which we are about to conduct you—not by the same route as that taken by the Prince and Princess (for the Boscawen Shaft did not exist at the period of our tale), but by one much more difficult and dangerous, as you shall see.
Before we go, however, permit us to add to the offence of digression, by wandering still further out of our direct road. There are a few facts regarding Botallack and mining operations, without a knowledge of which you will be apt at times to misunderstand your position.
Let us suppose that a mine has been already opened; that a “lode”—that is, a vein of quartz with metal in it—has been discovered cropping out of the earth, and that it has been dug down upon from above, and dug in upon from the sea-cliffs. A shaft has been sunk—in other words, a hole excavated—let us say, two or three hundred yards inland, to a depth of some forty or fifty fathoms,—near the sea-level. This shaft is perhaps nine feet by six wide. The lode, being a layer of quartz, sometimes slopes one way, sometimes another, and is occasionally perpendicular. It also varies in its run or direction a little here and there, like a wildish horse, being sometimes met by other lodes, which, like bad companions, divert it from the straight course. Unlike bad companions, however, they increase its value at the point of meeting by thickening it. Whatever course the lode takes, the miner conscientiously follows suit. His shaft slopes much, little, or not at all, according to the “lie of the lode.”
It is an ancient truism that water must find its level. Owing to this law, much water accumulates in the shaft, obliging the miner to erect an engine-house and provide a powerful pumping-engine with all its gear, at immense cost, to keep the works dry as he proceeds. He then goes to the shore, and there, in the face of the perpendicular cliff, a little above the sea-level, he cuts a horizontal tunnel about six feet high by three broad, and continues to chisel and blast away the solid rock until he “drives” his tunnel a quarter of a mile inland, which he will do at a rate varying from two to six feet per week, according to the hardness of the rock, until he reaches the shaft and thus provides an easy and inexpensive passage for the water without pumping. This tunnel or level he calls the “Adit level.” But his pumping-engine is by no means rendered useless, for it has much to do in hauling ore to the surface, etcetera. In process of time, the miner works away all the lode down to the sea-level, and must sink the shaft deeper—perhaps ten or twenty fathoms—where new levels are driven horizontally “on the lode,” and water accumulates which must be pumped up to the Adit level, whence it escapes to the sea.
Thus down, down, he goes, sinking his shaft and driving his levels on—that is, always following the lode ad infinitum. Of course he must stop before reaching the other side of the world! At the present time Botallack has progressed in that direction to a depth of 245 fathoms. To those who find a difficulty in realising what depth that really is, we would observe that it is equal to more than three and a half times the height of St. Paul’s Cathedral in London, nearly four times the height of St. Rollox chimney in Glasgow, and considerably more than twice the height, from the plain, of Arthur’s Seat, near Edinburgh.
When the levels have been driven a considerable distance from the shaft, the air naturally becomes bad from want of circulation. To remedy this evil, holes, or short shafts, called “winzes,” are sunk at intervals from the upper to the lower levels. These winzes are dangerous traps for the unwary or careless, extending frequently to a depth of ten or fifteen fathoms, and being bridged across by one or two loose planks. Ladders are fixed in many of them to facilitate progress through the mine. When a miner drives the end of his level so far that the air will not circulate, a new winze is usually sunk down to him from the level above. The circulation is thus extended, and the levels progress further and further right and left until they occupy miles of ground. The levels and shafts of Botallack, if put together, would extend to not less than forty miles, and the superficial space of ground, on and beneath which the mine lies, is above 260 acres.
When the lode is rich, and extends upwards or downwards, it is cut away from between levels, in a regular systematic manner, strong beams being placed to support temporary platforms, on which the miners may stand and work as they ascend. When they have cut all the lode away up to the level above them, a false timber bottom is made to replace the rocky bottom of the level which is being removed. Thus, in traversing the old workings of a mine one suddenly comes to great caverns, very narrow, but of such immense height above and depth below that the rays of your candle cannot penetrate the darkness. In such places the thick short beams that were used by the old miners are seen extending from side to side of the empty space, disappearing in dim perspective. Woe betide the man who stumbles off his narrow plank, or sets his foot on an insecure beam in such places! Where such workings are in progress, the positions of the miners appear singularly wild and insecure. The men stand in the narrow chasm between the granite walls above each others’ heads, slight temporary platforms alone preserving them from certain death, and the candles of those highest above you twinkling like stars in a black sky.