Page:De re metallica (1912).djvu/144

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102
BOOK V.

Now when a miner discovers a vena projunda he begins sinking a shaft and above it sets up a windlass, and builds a shed over the shaft to prevent the rain from falling in, lest the men who turn the windlass be numbed by the cold or troubled by the rain. The windlass men also place their barrows in it, and the miners store their iron tools and other implements therein. Next to the shaft-house another house is built, where the mine foreman and the other workmen dwell, and in which are stored the ore and other things which are dug out. Although some persons build only one house, yet because sometimes boys and other living things fall into the shafts, most miners deliberately place one house apart from the other, or at least separate them by a wall.

Now a shaft is dug, usually two fathoms long, two-thirds of a fathom wide, and thirteen fathoms deep; but for the purpose of connecting with a tunnel which has already been driven in a hill, a shaft may be sunk to a depth of only eight fathoms, at other times to fourteen, more or less[1]. A shaft may be made vertical or inclined, according as the vein which the miners follow in the course of digging is vertical or inclined. A tunnel is a subterranean ditch driven lengthwise, and is nearly twice as high as it is broad, and wide enough that workmen and others may be able to pass and carry their loads. It is usually one and a quarter fathoms high, while its width is about three and three-quarters feet. Usually two workmen are required to drive it, one of whom digs out the upper and the other the lower part, and the one goes forward, while the other follows closely after. Each sits upon small boards fixed securely from the footwall to the hangingwall, or if the vein is a soft one, sometimes on a wedge-shaped plank fixed on to the vein itself. Miners sink more inclined shafts than vertical, and some of each kind do not reach to tunnels, while some connect with them. But as for some shafts, though they have already been sunk to the required depth, the tunnel which is to pierce the mountain may not yet have been driven far enough to connect with them.

It is advantageous if a shaft connects with a tunnel, for then the miners and other workmen carry on more easily the work they have undertaken; but if the shaft is not so deep, it is usual to drift from one or both sides of it.

From these openings the owner or foreman becomes acquainted with the veins and stringers that unite with the principal vein, or cut across it, or

  1. This statement, as will appear by the description later on, refers to the depth of winzes or to the distance between drifts, that is “the lift.” We have not, however, been justified in using the term “winze,” because some of these were openings to the surface. As showing the considerable depth of shafts in Agricola's time, we may quote the following from Bermannus (p. 442): “The depths of our shafts forced us to invent hauling machines suitable for them. There are some of them larger and more ingenious than this one, for use in deep shafts, as, for instance, those in my native town of Geyer, but more especially at Schneeberg, where the shaft of the mine from which so much treasure was taken in our memory has reached the depth of about 200 fathoms (feet?), wherefore the necessity of this kind of machinery. Naevius: What an enormous depth! Have you reached the Inferno? Bermannus: Oh, at Kuttenberg there are shafts more than 500 fathoms (feet?) deep. Naevius: And not yet reached the Kingdom of Pluto?” It is impossible to accept these as fathoms, as this would in the last case represent 3,000 feet vertically. The expression used, however, for fathoms is passus. presumably the Roman measure equal to 58'! inches.