Bisbee daily review., 1911-08-27

the two largest electrically driven
 hoists in the country, and the skin
 looks like a box car as it comes from
 the levels and dumps into the bins
 No. 1 equipment is complete and in
 operation. while at No. 2 the machin-
 cry is being installed. The No. 1
 mine has the greatest amount of de
 vebpment. and work identical to this
 Is forming in the No. 2 Each lever
 is developed exactly as the one above, excepting in the traction ways
 no timbers are used. The method of
 handling the ore is interesting. The
 underground ore trains are of f2 cars,
 each having five tons capacity. The
 electric engine brings the train to a
 tipple and through it, leaving the last
 tEIee ears. These are automatically
 fastened in the tiDple. when the tip
 pie turns. dumping the loads into bin over an incline, when the cars are
 shunted out and three more run in,
 and so on till the entire train has
 been disposed Of The ore bin be- heath the tipple is Of concrete. The cars have no doors, nor openings at
 side or end, but are simply steel boxes containing five tons. They are
 equipped exactly as are the freight cars on transcontinental railroads,
 with ,stTaight-air brakes. Nj. c. B. couplers, etc. From the bin, by means of air-operated steel gates, the ore is dumped into guage hoppers, contain
 ing a full load for the skip. The skip is lowered below the guage, when the bottom bf the hopper is pulled out and the load instantly drops into the skip. The skip is brought to the sur face and dumped into a receiving bin.
 Here, also, by means of zir-operated steel gates, the ore is sent over griz-
 zlies and into No. s Gates gyratort crushers by gravity. From the gyra- tories the ore goes to two sets of Gar field rolls. 72x20, these two processes dressing to one inch. Below the rolls there is a travelling belt which takes the ore to a carrier belt, which dis
 tributes the material into the bins. the latter having total capacity of
 20,000 tons. There are three rail way tracks beneath these bins, the trains being run under and loaded by means of hand-operated gates. The
 dressing of the ore to proper size for milling is somewhat unique for this section, and the economy is in stantly apparent No handling is nee essary at the mill, better and quicker work is done, and the cars receive the maximum load with no unified spaces. Power for all this, for the machines, for the hauIage engines in the mines, for lighting. etc, is gene-- ated in the power plant at Hayden. The power transmission line is first class, with steel towers.
 At Ray is elucidated the most ad. vanced method of the caVing system. and on a very large scale. The es- sence of the system here is to cave in such manner that the capping will not crumble and thus become mixed with the ore. and for the winning of large quantities Of ore constantly. Every move is exactly determined be, fore it is undertaken: and thus throughout the mine all tracks are laid Q grade, the same as on trans continental railways. The coordinate will be numbered zero, and all opera tions numbered from that point the same as the laying out of the streets in many cities. Thus the first open ing off the tramway will be 1 s, 1 E.. or 100 feet south and east of zero, and so on. The sill floor of each stope is 9 feet above the traction level, and each stope is given a figure show ing its location from the central point
 The thing sounds simplicity itself. as it is; but the practice here is to simplify this simplicity. Tn the lat erals manways are driven. upward every 100 fett, going to the capping, and through these the miners pass into the stopes at convenient points. The stopes are 30 feet in width. leay- ing between each a pillar of 20 feet of ore. The miners strip the sides of the stope, and in blasting the backs come down without further work. The ore is scanned and very friable. The stope is carried to the capping. and the pillar holds the capping. Large areas are So stopped, but a small DOT. ton of the ore being drawn, and this only in order to assist in the break ing down of the backs at the shooting of the holes, the weight of the ore aiding this process materially. When the time comes for drawing the ore from the Slopes. small s1opes are driven upward in the pillars for 20 feet, and on either side a great many holes will be drilled. These are shot in rotation during one shift, the re- suit being that the base of the pillar is undermined completely. Then the carmen are put to work drawing ore.
 there being two chutes from each stope, one on either side of the track, and a chute for the pillar stope By
 the ordinary engineering methods the quantity of ore in the ground be- ing caved is known almost exactly, so there is no guesswork about draw ing out the supply. In drawing the ore larger portion Is taken from the rear end of the stope than from the front This permits the ore and the
 capDing to settle uniformly and in
 conformity with the contour of the ground originally. and thus the cap ping is kept entirely free from the ore. To be certain that the ore is drawn las it should De, a central
 station is maintained, which every car must pass. Here the checker takes the number of the car, from whence it was filled, and the name of the man in charge, thus keeping all rec ords. To give an idea of the small quantity of waste I must state that fhara ara suto hfno oua Tor tho ora