230 mindnG industry. 



machinery in a mill, working silver ores by the method described in the fore- 

 going pages, may be illustrated by a drawing on Plate XXIII, which presents 

 a sectional view of the building and the more important machines employed 

 in it. 



The batteries of stamps, as many as there may be, are arranged in one 

 straight line. Behind them, that is on the feed side, is the breaking floor, 

 where the rock is prepared by a stone-breaking machine, or, in its absence, by 

 hand. When the slope of the ground permits it, large bins are sometimes 

 constructed above and behind the breaker, into which receiver the wagons or 

 cars bringing the ore from the mine may discharge their contents. As the 

 outlet of the bins is on a higher level than the mouth of the breaker, the rock 

 is delivered to that machine without much handling. Such bins, where prac- 

 ticable, are of great advantage in providing a reserve of ore for the mill when- 

 ever communication with the mine is interrupted for a time. The batteries 

 discharge the crushed ore upon an apron, or, as in the case illustrated, into a 

 trough, or launder, which conveys it to the settling tanks. These stand di- 

 rectly in front of the batteries, though in some mills, for lack of space, they 

 extend along the adjacent side of the building. A platform is usually pro- 

 vided upon which the pulp may be deposited when shoveled out of the tanks. 

 Some mills are so arranged as to use a car, in which the pulp is moved from 

 the tanks to the pans. This is especially necessary when the tanks are more 

 remote from the pans, or when the latter are arranged in a line at a right an- 

 gle to the line of the batteries. 



Generally the pans are arranged in a straight line, parallel to the line of 

 batteries, as in the case illustrated. The separators stand in front of the pans, 

 arranged in a parallel line, and on a sufficiently lower level to permit the charge 

 of the pan to run into them. Below the separators are the agitators or other 

 similar contrivances for the purpose of preventing the escape of quicksilver or 

 amalgam. The power is usually communicated from the steam-engine or other 

 motor, by gearing or belting to a line-shaft which is placed in front of, and par- 

 allel with, the line of batteries. On this shaft are pulleys, opposite to those of 

 the several cam-shafts, to which they transmit, by belting, the power necessary 

 for the stamps. The same shaft imparts motion, by means of countershafting 

 and belting, to the rock-breaker and to the pans. For the latter a line of 



