California Journal of Mines and Geology Volume 8

California Journal of Mines and Geology Volume 8

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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. 1888 edition. Excerpt: ... at one time to be worked by a new shaft, down stream from the main shaft, but so much water was encountered, that the dram tunnel became a necessity and now serves to drain the whole mine. The object in working from a shaft is to obtain grade for washing and storage for tailings, the latter a point of great importance. The mine is ventilated by a Baker blower, driven by a Pelton water wheel; there heing also an engine, which may be used for the purpose. The air pipe reaches the main shaft at a depth of sixty feet through a tunnel. The design in this arrangement is to insure a continual air.supply to the mine in case of the burning of the hoisting works; also, in such event, to afford means of escape for the miners--an example which should be followed in other and similar situations. The hoisting works contain a forty-horse power steam engine, with two boilers, and are well arranged and equipped. Flat cables are used, and one car comes up as another goes down, which saves one quarter of the cost of hoisting, and lessens the strain and shock on the machinery. Safety cages are employed, and the shaft remains covered by a bonnet until a cage comes up, and in this wise accidents are avoided. There is a Cornish pump of ample power in readiness, but there has been no occasion for using it since the drain tunnel was opened. For hoisting, three cords of pine wood are consumed daily, at a cost of $2 85 per cord delivered. This is a rather dangerous mine to work, the gravel being loose, and bowlders numerous, while the roof is sandy and requires timbers for its support. These, being indispensable, form a considerable item of expense. Various kinds of timber are used. Posts, brought from a distance of two miles, cost 3 cents per running foot, delivered at...show more

Product details

  • Paperback | 502 pages
  • 189 x 246 x 26mm | 889g
  • Rarebooksclub.com
  • Miami Fl, United States
  • English
  • black & white illustrations
  • 1236662776
  • 9781236662774