THE WORLD’S BIGGEST PUMP.
In a letter to the Chicago Record from Houghton, Mich., a correspondent describes the Calumet and Hecla pump, named the Michigan, and the largest in the world. It can deliver 2,500,000 gallons of water every hour in the 24 without being crowded to its limit of capacity, and it will do the work with scarcely as much noise as is made by the operation of an old-style sewing-machine. Outside the doors of the great building which houses it, no sound is heard from within, and, standing beside the monster, upon the brink of the pit connected with the lake from which the water is taken, almost the only sound heard is the noise of the suction, as with every stroke more than 1,000 gallons are lifted. Briefly, it is a triple expansion pumping-engine, with a capacity of 60,000,000 gallons, standing nearly 50 feet in height and requiring 1,500 horse-power for its operation. It has been proved by actual tests that the nominal capacity can be easily maintained for an indefinite time without injury or strain, and that pushed to its full capacity the pump could handle approximately 75,000,000 gallons in 24 consecutive hours. The duty of the pump is to furnish water for the great stamp mills of the Calumet and Hecla Company, which has 22 steam pumps in continuous operation, daily pulverizing 5,000 tons of conglomerate rock into sand so fine that it can be carried away by a stream of swiftly running water. The pump is housed in a special building near the shore of Torch Lake, and below the mills, and it forces a steady stream of water to the upper portions of the mills, where innumerable small jets play upon the great slime tables and jigs. Here the specific gravity of the fine particles of copper contained in the rock separate the mineral from worthless sand, and the size and force of the streams of water are so nicely regulated as to wash away the sand and yet carry with it the minimum of copper.