A textbook on mining engineering, Volume 6 by International Correspondence Schools

Author:International Correspondence Schools
Language: eng
Format: epub
Publisher: International Text Book Co., 1900

PlO. M.

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SURFACE ARRANGEMENTS

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and a special trolley c connected to the rope above the skip. Another view of the trolley is shown in Fig. 24, from which it can be seen that the trolley is simply a heavy axle provided with a pair of wheels, to which a yoke and clamp are attached, so that it can be placed on the rope at any point above the skip. The timber is rolled across the shaft on rollers, as shown in Fig. 23, and its end chained to the trolley, as shown at c. After this, the skip is hoisted and the trolley drags the log up the incline until the back end of the timber drops over the collar of the shaft d and into the skip, as shown by the dotted lines. In this way very large and heavy logs for use in timbering stations or pump-rooms can be transported through the shaft.

65. Transporting: Timbers Doinrn a Vertical Sliaft. —Where it is necessary to take ordinary timbering down a vertical shaft, it is sometimes accomplished by hanging logs under the skip or cage. Fig. 25 illustrates a clevis arranged for this purpose. A hole is bored through the timber a little over 1 foot from the end and a bolt inserted, by means of which,and the clevis or tongs, the timber is suspended beneath the cage or skip and lowered into position. A spike or dog is driven into the lower end of the timber and a short piece of rope attached to it, which can be used in steadying the piece before it is lowered and in drawing it to one side while landing it at the bottom of the shaft. Sometimes, in place of a clevis and bolt, a pair of tongs, with the points shaped like the point of a cant-hook, are employed. Fig. 26 shows one point of such a pair of tongs. When these tongs are employed, the points are simply driven into the log. At other times, dogs

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