This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1909 Excerpt: ... be delivered at the proper point away from the shaft. These, and other considerations, have led to hoisting the car and load together to the mouth of the shaft. This effects a great saving of time and labor, and wear and tear of apparatus. It is the method adopted in the mines upon the Comstock Lode, and in all ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1909 Excerpt: ... be delivered at the proper point away from the shaft. These, and other considerations, have led to hoisting the car and load together to the mouth of the shaft. This effects a great saving of time and labor, and wear and tear of apparatus. It is the method adopted in the mines upon the Comstock Lode, and in all wellappointed vertical shafts of any considerable depth elsewhere." Ore Pockets Beneath the Levels This was before the day of cutting ore pockets beneath the stations, and before the day of automatically loading and dumping skips. It is true that skips had, even prior to that time (1870), been arranged to dump automatically upon reaching the surface, but the skips were comparatively small, and the running speed of the hoisting engines was not great. To-day the ore pocket beneath the stations, skips of large capacity, fast-winding engines, and automatic devices, have come to be recognized as necessary to the economical hoisting and handling of ore. So important has this become, and so great the decrease of cost from that of hoisting by cages, that many of the largest and deepest mines of the United States have within a recent period made expensive changes in their shafts, and have substituted skips for cages. Among the mines having made or making this change are several at Butte, Montana, the Calumet and Hecla copper mine at Houghton, Michigan, with its miledeep shafts; the Copper Queen mine, at Bisbee, Arizona, and the Homestake, at Lead, South Dakota. It is not a matter of preference, merely, but, it has been clearly and repeatedly demonstrated that hoisting a given tonnage with skips can be done more rapidly and at less expense than by any other means at present in use. Stations should le cut at the time of sinking. When the shaft reaches the...
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