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HOISTING PLANT, PASCOE SHAFT, REPUBLIC, MINE.

arc and incandescent lighting. This dynamo was replaced by a General Electric 150 K. W. revolving field, compensated type alternating current generator running 600 R. P. M. and generating a 3-phase 60 cycle current at 2,300 volts. The switchboard for the new generator contains 3 panels; a generator panel, one double feeder panel, and one single feeder panel, shown in Fig. IV.

On the generator panel are 3 ammeters, a volt meter, 2 indicating wattmeters, Rheastat and the necessary switches. The double feeder panel has 6 fuse blocks, 2 ammeters, 2 switches, and the single feeder panel, 3 fuse blocks, I ammeter, and I switch. Three sets of distributing lines leave the generator house, one from the right side of the double feeder panel to No. 9 electric underground pump, one from the left side of double feeder panel to surface motors, and one from the single feeder panel to the lighting circuit.

New boilers having been installed in this house the pressure on the 12"x36" engine running the generator was increased from 70 lbs. to 130 lbs.

In order to get a proper belt speed the diameter of the fly wheel was increased from 10 ft. to 11 ft. by hardwood lagging, (shown in Fig. V), and the engine speed increased to 135 R. P. M. Some doubt was entertained as to the reliability of a Corliss engine running at this speed. A little trouble was experienced the first day with the dash pots, but after renewing the leather packing in them, the engine gave no further trouble. This electric outfit drives the following motors:

One 50 H. P. form L Induction motor running 720 R. P. M., driving an underground pump. One 10 H. P., 1,200 R. P. M., also running an underground pump. One 71⁄2 H. P., 1,200 R. P. M., running the machine shop. One 20 H. P., 900 R. P. M., running the carpenter shop and coal tram. One 30 H. P., 900 R. P. M., form M. variable speed Induction motor, running a surface tram.

The pumping problem at Republic is quite insignificant compared with the majority of iron mines. An average of 75

or 80 G. P. M., with a storage capacity ample to allow a stoppage of pumping for 2 or 3 days. This water was originally handled by a Cornish pump, the rods of which worked in a shaft having 7 slight bends in it. None of these bends were made by joints or bobs, but by forcibly springing the rods, thus increasing the friction very much. The pump was run by a 20"x30" flat slide valve, link motion engine running on a steam consumption of 56 lbs. per I. H. P. per hour,

The new electric pump (Fig. VI.) installed on the 1,153' ievel is a Deane 434"x12" vertical single acting triplex double back geared to the 50 H. P. motor mentioned above. This pump runs 36 R. P. M. throwing 90 G. P. M. A check valve in the discharge line and a by-pass between the discharge and the suction allows the pump to be started with only the friction load.

The wires are led to the pump room down the shaft through a 11⁄2" wrought iron pipe. Half way down the shaft the pipe enters a cast iron junction box some 6" square by 4 ft. long, where a splice is made and the weight of the lower half of the wires is supported. The only fault found with this pump is the noise it makes. The motor pinion is rawhide and the second pinion fibre, gears are cut. The efficiency of motor, and pipe line is 65%, i. e., the work in water delivered at the top of the shaft is 65% of the work leaving the transformers.

The 20 H. P. motor in the carpenter shop drives a planer, band saw, rip saw, boring machine and by means of a wire rope transmission, an aerial wire rope tram. The tram is used to haul coal from the coal dock to No. 5 engine house, a distance of about 1,200 ft. Two 14" wire ropes were stretched over the supports 6 feet apart and one bucket is used on each rope.

The hoisting rope makes one-half lap around a 6 ft. wood filled sheave at the lower end of the tram, which sheave is driven by a double bevel paper and iron friction gear (Fig. VII.) The two bevels are run by the rope transmission from the carpenter shop. The two buckets run in balance, one dumping at No. 5, while the other is being filled at the coal dock.

One of the paper frictions pulls the hoisting rope in one direction, the other in the opposite direction.

The buckets are automatic, being hung from a point 1" below the center of the end. The shape of the bucket is shown in Fig. VII. The top is wider than the bottom thus making the load top heavy although the bottom is heavier, when the bucket is empty. Therefore when the catch is released, the bucket dumps and immediately rights itself. The catch that keeps it from dumping, extends below the bottom several inches. As the bucket comes toward the pocket, Fig. VIII., with its load of 1,000 lbs., the sag in the rope is enough to allow the catch to strike the edge of the pocket. The bucket, then being dumped, is so much lighter, that the tension of the supporting rope raises the bucket enough for the catch to clear the pocket going back. The speed of hoisting is 450′ per min.

PASCOE TRAM.

The hauling of the ore from Pascoe shaft house to the pocket and stock pile is done in an automatic dump car, shown in Fig. IX., run by a 30 H. P. reversible, variable speed motor. The car is pulled by an endless rope which makes 4 half laps around a 3 ft. driving drum, and three half laps around three independent sheaves thus largely eliminating the differential action caused when two solid drums are used instead of one drum and independent sheaves as above. The motor is geared to the drum shaft, no friction clutch being used. The speed of the car is 1,200 ft. per minute.

PASCOE SHAFT.

The hoisting from Pascoe shaft was originally done from Ely engine house, with a small skip running 500 ft. per min., over a very crooked skip road.

Because this shaft was to be the principle shaft of the mine, and to allow the closing down of another engine house, a new hoist was put in an addition to the building over the Allis compressor. While this hoist was being erected the skip road was straightened, widened, a double track laid, and a new steel shaft house erected. (Fig. IX.) The foundation for the shaft

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