The Elements of Mining Engineering (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1900 Excerpt: ...or leaching process, in conjunction with the freight rates, frequently determines whether the ore is to be treated on the spot or shipped to the nearest smelter or reduction works. In the case of gold-bearing sulphides, the method of treatment most commonly employed is a combination of both milling and smelting. The ore, if it contains any free gold, is crushed under the stamps, and any gold which may be freed from the pyrites is caught and taken into solution by the amalgamated plates of the battery. The rest of the crushed ore is passed over suitable apparatus, by means of which the light gangue materials are washed away and the heavier sulphides left, thus greatly reducing the ore in bulk, while retaining practically all the values. The sulphides, or "concentrates," are then shipped to the nearest smelter or reduction works for the final treatment. These processes are more fully described under the heads of " Amalgamating Machinery" and "Concentrating Machinery," while the stamp battery will be treated for the present only as a crushing machine. 23. The Stamp.--The stamp proper consists of a wrought-iron or steel "stem," 3 to 4 inches in diameter and 10 to 14 feet long, a cast-iron "head" or "boss," about 8 inches in diameter and 15 inches to 2 feet long, and weighing from 200 to 400 pounds, and a chilled-iron or steel "shoe." The two ends of the stem are interchangeable and slightly tapered, forming blunt conical wedges, the lower one of which is fitted tightly into a corresponding hole in the upper end of the boss. In the bottom of the boss is another hole, similar to that in the top, but larger, into which the conical shank of the shoe fits loosely, being wedged in by strips of wood...