A LOW-GRADE STAMP MILL. 47 



Note by Translator. — We think that L' Eglise undoubtedly alluded to the 

 Reynolds and Henry Passes of the Rocky Mountains, where the head sources of 

 Jefferson and Madison Forks are not over one and one-half miles from Henry's 

 Lake, the main head of Lewis' Fork of the Columbia. I have surveyed and ex- 

 amined that locaUty personally. 



MINING AND METALLURGY. 



A LOW-GRADE STAMP MILL. 



MRS. FLORA ELLICE STEVENS. 



The low grade ores are distinguished from those of the higher class, as in 

 the former instance there is less of the precious metals to the quantity of ore than 

 in the latter, and consequently the method of treating the low, or poor grade must 

 be different from that acceptably employed for the richer mineral ; for it is far too 

 expensive to use the same means of treatment with that running. fifteen or twenty 

 ounces to the ton, as would pay well in the ore running several hundreds. Of 

 course it must be remembered, that I am speaking of silver ores, as the barest 

 trace of gold will always pay for working. 



But iji a general silver region, particularly where the ore is found in the 

 level ground, instead of among the mountains, there are a great many claims, 

 which would pay well if they were worked by an inexpensive method of treat- 

 ment. A stamp mill built to meet this exigency, I had the pleasure of visiting, 

 a description of which f will endeavor to give, though it will necessarily be less 

 full and complete than I would desire, as it has been a year since I examined the 

 mill, and most of my notes made at the time have been lost. 



The mill is built upon the side of the hill, as by this means an advantage 

 will be gained in the distance the ore cars are to be raised. About five hundred 

 yards away is the mine. A tramway, perhaps a foot and a half wide, connects 

 the two, along which iron cars carry the ore, drawn by horses a la tandem. The 

 cars run directly on to the elevator, and are hoisted to the ore or quartz house, 

 which is the very highest division of the mill. This room is 1 6 by 75 feet. 



The ore is "dumped" over iron screens, the fine ore dropping down to the 

 bins, and the coarse ore falling on to the breakers, just above these, for crush- 

 ing. The breakers in this mill were Blake's improved, with a capacity of a 100 

 tons per day. As the next step, the ore is taken from the chutes to the self-feeders, 

 which are fed automatically by the dropping of the battery. The battery room 

 is 36 by 75 feet, and the building increases in width as we go down in about the 

 same ratio, to make room for the machinery, which now becomes necessary. 



