Electric Mining at Brownsville; large glass insulators used

ELECTRIC MINING AT BROWNSVILLE, PA.

BY ALFRED E. BRADDELL.

As a means of saving labor and time, electricity is now rapidly coming to the fore to replace, in a great measure, the pick and shovel in coal mines. A plant has recently been installed in the mines operated by the Redstone Oil, Coal and Coke Co., situated near Brownsville, Pa. The plant consists of a United States generator (80 h. p.) 250 volts, driven by a 200 h. p. engine made by C. C. Cooper, Mt. Vernon, Ohio, with two boilers manufactured by the Altoona Mfg. Co., of Altoona, Pa.

The generator is not driven direct from the engine bat from counter-shafting. The fly wheel of the engine is 142 1/2 inches in diameter, which is belted to a pulley of 42 inches diameter, placed on one end of the counter-shaft. On the other end of this is a pulley 60 inches diameter, which in turn is belted to a 30 inch pulley on the generator. The motors were manufactured by the Jeffrey Mfg. Co., of Columbus, Ohio, there being two in operation at the present time. These motors are of very solid construction in order to withstand the rough usage applied to them by the miners, as they have necessarily to be shifted about to the various parts of the mine, and, in order to do this, crowbars, etc., are called into requisition.

The feeders from generators are stranded, insulated cables, No. 0000 B. S. each. These are brought down the shaft, which is 280 feet in depth, and run along what is known as the "main heading," being supported on large glass insulators placed on wooden brackets, the opposite poles kept about 8 inches apart From this main heading run the "butt headings," and No. 0 B. S. bare conductor is used here. The mine is then divided into rooms placed about 33 feet apart, and into these rooms come the taps conveying current to the motors. Bare conductors (No. 2 B. S.) are also used here, being supported in the same manner as the feeders. All connections are made by means of clamps, which can readily be adjusted, at the same time securing a good contact Connection to the motor is made through a stranded twin cable heavily insulated, about 100 ft in length. This is coiled on a reel or drum which rotates as the motor moves forward daring operation. This operation consists of under-cutting the coal by a series of revolving teeth for a distance of 6 ft. and about 18 to 20 inches in width. This is calculated to be equal to 4 tons of coal, and on timing one of these machines it was found to have taken exactly 4 minutes to do the work. When the machine has under-cut along one side of the room the coal is blasted so that it can then be easily removed with the shovel. Three men are in charge of the machine, and it is certainly an engrossing sight to watch these unskilled toilers handling, with the greatest of ease and the utmost indifference, such a powerful, yet unseen, force. It was, in truth, a verification of the saying: "You push the button, we do the rest" These men simply turned the switch and the current did the rest.