596 MINING INDUSTRY. 



stephanite, pyrargyrite, proustite, polybasite, fahlerz, antimonial silver, and na- 

 tive silver. The rich silver minerals seem to be less abundantly distributed 

 in the Brown than in the ores of the Terrible, though some lots of selected 

 ore have proved to be very rich. The ore is sometimes concentrated in one 

 compact seam, lying upon one wall, or is sometimes divided into several 

 branches. The width of the seam may be from 2 to 10 or 12 inches. 



Fig. 3, on Plate XXXV, shows a cross section of this vein, observed by 

 the writer, not far below the surface. The north wall is well defined, carry- 

 ing seams of rich ore; the south wall is not so clearly identified, the left hand 

 side being limited by the side of the drift, and the true character of the ad- 

 joining rock remaining undetermined. The mass of gangue rock here is a 

 mixture of quartz and feldspar, much broken up, traversed by clefts and joints 

 and colored by oxide of iron. The several seams of ore appear to imite at a 

 point not far below that where the section was taken. 



The mine has been opened by a tunnel, 180 feet long, through the coun- 

 try-rock, at a right angle to the vein, which it strikes at 160 feet below the 

 surface. From this point of intersection a drift has been made, about 180 

 feet on the vein. A tunnel or adit, starting from a point about 100 feet higher 

 than the drift just mentioned, has been driven in on the vein from its outcrop 

 in the neighboring ravine, about 250 feet in length, and connected by winzes 

 with the drift below. In connection with all this work considerable stoping 

 has been done. 



The company owning this mine have expended a large sum of money in 

 the development of the property, chiefly, hovi^ever, in the construction of met- 

 allurgical works and other appurtenances* As the mine is worked by tunnels, 

 no hoisting machinery has been required, but a large and costly crushing mill 

 and smelting furnaces have been built at the base of the hill, just below the mine. 

 These works consist of 20 stamps, a Blake's rock breaker, some concentrating 

 appliances, a roasting furnace, lead-smelting furnace, and cupelling furnace. 

 Some details of the various methods of treatment applied to the ores of the 

 district will be found further on. It will suffice to say here that the first-class 

 ore is crushed without concentration, while the bulk of the mine product is 

 reduced by stamps, concentrated in a round buddle, and the richer portion ob- 

 tained for roasting and smelting. The ore of this lode is rather too poor in 



