Page:Popular Science Monthly Volume 61.djvu/243

Rh four lateral tunnels are driven from the shaft along the surface of the bed-rock, and opened out in a fan-like manner to the limits of the claim. The outermost portions are worked out first, and as the excavation is carried back to the shaft, the roof and overlying muck are allowed to cave in and settle down on to the bed-rock. Timbering is thus entirely avoided. This absence of timbering in the Klondike shafts and tunnels is one of the most striking features in the mining; the frozen ground requires no support—it never thaws—and chambers as much as 100 feet square are covered by an icy roof which never breaks down.

The operations in the creeks are carried on upon a very considerable scale, and there is a large amount of machinery in the country; upon some groups of claims the work is not carried on by sinking and drifting, but is more of the nature of open quarrying. Night work is prosecuted by electric light or the acetylene lamp.

Formerly the raising of the gravel and its storage in dumps were mainly carried on in the winter, and the sluicing in the summer, and enormous winter dumps were accumulated for summer work. This last year the greater part of both has been carried on simultaneously during the summer, and it seems likely that the winter work will become less usual, and may even be abandoned altogether.

The mining upon the hillside claims bears no resemblance in appearance to ordinary placer mining. Horizontal tunnels are driven into the White Channel from the face of the hill, and shafts are sunk into it from the surface in a manner that more nearly resembles the working in ordinary metalliferous lodes. In one such mine which I visited, a horizontal tunnel 700 feet in length had been driven into the gravel, and at right angles to this, and at intervals of about 60 feet, lateral tunnels were being driven to a distance of 70 feet on either side; and there were 200 feet of pay gravel above the tunnel; the men were working with pick and shovel at the end of the long tunnels, and cars of rock were being wheeled along a tramway to the head of the long wooden shoot which carried the gravel down to the creek.

In these high-bench claims, as they are called, two great difficulties are encountered: (1) the difficulty of disposing of the tailings, which cannot be allowed to slide down upon the creek claims but must be artificially banked up; and (2) the difficulty of obtaining water at this height. Both have cooperated to prevent hydraulicking, which would otherwise be the obvious way of working gravels situated upon a steep hillside.

On Hunker Creek, however, Mr. Johanson, who owns both creek and hillside claims, has, with much enterprise and at very great expense, introduced hydraulicking upon a considerable scale. The