Scientific American Supplement, No. 508, September 26, 1885 eBook

This eBook from the Gutenberg Project consists of approximately 130 pages of information about Scientific American Supplement, No. 508, September 26, 1885.

Scientific American Supplement, No. 508, September 26, 1885 eBook

This eBook from the Gutenberg Project consists of approximately 130 pages of information about Scientific American Supplement, No. 508, September 26, 1885.
Hale & Norcross and Savage shafts, producing a good circulation of air both in the shaft and in the mines mentioned.  At this point, on account of the inflow from the mines consequent upon connecting with them by means of the drift, they had more water than the Cornish pumps could handle, and introduced the hydraulic pumps, which pumps are run by the pressure of water from the surface through a pipe running down from the top of the shaft, whereas the Cornish pumps are run by huge steam engines.

By means of the hydraulic pumps they were enabled to sink the shaft to the 2,600 level, and extended the Cornish pumps to that point, where another set of hydraulic pumps was put in.  They then sunk the shaft to the 2,800 level, when they ran another drift westward, and tapped the vein.  The prospects at this depth in the Hale & Norcross and Chollar mines were so encouraging that the management decided to sink the shaft to the depth of 3,000 ft.  On reaching the 3,000 level, they ran a third drift through to the vein.  The distance from the shaft to the east wall of the vein was found to be only 250 ft.  At the depth of 3,000 ft. they put in one of the pair of hydraulic pumps that is to be set up there.  The second pump is now arriving from San Francisco, and as soon as the several parts are on the ground, it will be at once put in place alongside its fellow on the 3,000 level.  This additional pump will increase the capacity from 600,000 to 700,000 gallons in twenty-four hours, or about forty-five miners’ inches.

Owing to the excellent showing of ore obtained on the 3,000 level by the Hale & Norcross Company, and to the continuation of the ore below that level (as shown by a winze sunk in the vein), the management determined to sink the shaft to the vertical depth of 3,200 ft.  It is now 3,120 ft. deep, and it is safe to say that it will reach the depth of 3,200 ft. early in September, when it will lack but eighty feet of being as deep as the shaft at Przibram was at the time of the great festival.  Although the shaft is of great size—­about thirty feet by ten feet before the timbers are put in—­the workmen lower it at the rate of about three feet a day, in rock as hard as flint.

The hydraulic pump now working at the 3,000 foot level of the shaft is the deepest in the world.  In Europe the deepest is in a mine in the Hartz Mountains, Germany, which is working at the depth of 2,700 feet.  It is, however, a small pump not half the size of the one in the Combination shaft.  Although these pumps were first used in Europe, those in operation here are far superior in size, and in every other respect, to those of the Old World, several valuable improvements having been made in them by the machinists of the Pacific coast.

The capacity of the two Cornish pumps, which lift the water from the 2,900 foot level to the Sutro drain tunnel (at the 1,600 level), is about 1,000,000 gallons in twenty-four hours, and the capacity of the present hydraulic pumps is 3,500,000 gallons in the same time.  They are now daily pumping, with both hydraulic and Cornish pumps, about 4,000,000 gallons, but could pump at least 500,000 gallons more in twenty-four hours than they are now doing.  The daily capacity with the hydraulic pump now coming, and which will be set up as mate to that now in operation at the 3,000 foot level, will be 5,200,000 gallons.

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Scientific American Supplement, No. 508, September 26, 1885 from Project Gutenberg. Public domain.