564 MmiNG IOT)USTEY. 



the processes employed for their further treatment, as will be shown further 

 on, are such that not only a large percentage of the remaining gold, but also 

 of the silver and copper are extracted. Some of the methods of concentra- 

 tion will be briefly noticed before proceeding to describe the Smelting 

 Works. 



The blanket sluices resemble generally those that have been already 

 described in the chapter treating of milling in Nevada. They consist of a 

 simple sluice or flat-bottomed trough, one or two feet wide and of indefinite 

 length, the sides of which are formed by two strips of wood, two or three 

 inches high. The sluices are slightly inclined, so that the stream may flow 

 readily. On the bottom of the sluices are laid coarse blankets. The stream 

 of tailings is allowed to run over these sluices and the heavier particles of ore 

 lodge in the blanket, while the lighter particles are swept away. The blankets 

 are washed out at regular intervals. The material obtained is usually a rich 

 concentration. One lot of over 14 tons of blanket tailings sold by the Ophir 

 mine to the Smelting Works gave, by assay, 12 ounces of fine gold and 10 

 ounces of fine silver to the ton. The price paid for this lot was $210 per 

 ton. Their yield, however, is not regular, and not often so high. In the 

 Ophir mill they are usually treated in a small Bartola pan, a machine resem- 

 bling somewhat in general character the common grinding pan described in 

 a previous chapter ; the yield obtained varies very much, sometimes quite high, 

 sometimes quite low, but is most frequently stated at about $20 or $25 per ton, 

 in coin. The greater part of the tailings is subsequently treated in common 

 square buddies. The huddle is a long wooden box, about 4 or 5 feet wide, 10 feet 

 long and 15 inches deep, fixed at a gentle inclination, so that the stream may 

 run down through it readily, and so arranged that water may be supplied at 

 the head, or upper end, and distributed evenly over the whole width of the 

 table. The tailings are fed at the top, being thrown upon an apron above the 

 head and washed down into the box by the stream. The workman, standing 

 at the side, by means of a broom or light scraper assists the even distribution 

 of the material, and by sweeping it very gently upward, toward the head of 

 the box, aids the separation of the heavier from the lighter particles, the 

 former remaining near the head, the lighter being swept away by the current. 

 When the huddle is full the contents are divided into three equal parts ; that 



