The Two California Mills.
The California stamp and pan-mills in Virginia City reduce the ores of the Consolidated California and Virginia Mine. The stamp-mill is situated immediately east of the C and C shaft of the mine. It contains eighty stamps. The ore crushed in this mill is amalgamated in the pan-mill, which stands about 1,500 feet further east. The crushed ore is conducted from the stamp-mill to the pan-mill through an iron pipe four inches in diameter. The process of amalgamation is much the same as at the Chollar Mill, except that the pulp goes directly into the amalgamating pans instead of being first received in settling tanks. It flows from pan to pan—the outflow of the first pan passing into the second through a pipe, thence into a third, and so on and from settler to settler, being in all about three hours in passing through the series. This is called the Boss Continuous Process. It is in use in no other mill on the Comstock, as yet. In connection with the Rae electrical process of amalgamation (in which a current of electricity is passed through the settlers) it is found to work satisfactorily. The electric current prevents loss of “floured” quicksilver. Both mills are driven by Pelton water wheels. A single Pelton wheel eleven feet in diameter, placed on the surface, drives the eighty stamps of the battery-mill, and also twelve Boss grinding pans. The water used on the surface Pelton is caught up and conducted to the C and C shaft, where it is used on a series of Pelton wheels of the same size. These wheels are placed in chambers made for their reception 500 feet apart from the top of the shaft down to the Sutro Tunnel level (there 1,500 feet), and by means of steel wire cables, used as belts, the power of all the lower wheels is brought to a main driving shaft on the surface. The whole power is then transmitted to the pan-mill (about 1,600 feet) by means of steel wire cables passing over pulleys placed on a series of tall wooden towers. The cables pass over a considerable depression between the top of the C and C shaft and the pan-mill; three high towers are required in the middle portion.