COLLECTIONS IN ECONOMIC GEOLOGY AND METALLURGY. 89 



matter, and is purified by treating in a keeve and on baddies, accord- 

 ing to the scheme shown in figure 7. 



No. 1 copper is dried and the silver picked out of it by hand. Tlie 

 ragging is also dried and then sifted. The finest copper sittings are 

 mixed with No. 4 mineral, and the coarse siftings with No. 3, while the 

 rock containing inclosed copper is returned to the stamps. 



All the mineral is packed in old oil barrels, and, with the exception 

 of No. 1, is shipped wet, as it comes from the jigs, to the smelting works. 



The slimes that will not settle in the hydraulic se])arators pass 

 through four laige settling boxes, and are treated according to the 

 scheme shown in figure 8 yielding No. 3 and No. 4 copper. 



The finer tails passing to the tail house are treated according to the 

 scheme shown in figure 0, yielding No. 5 copper. This treatment in 

 the tail house serves almost exclusively as a check upon the work of 

 the mill, by showing when too much copper is passing out in the tails. 

 When the mill is running properly there is not sufficient copper re- 

 moved in the tail house to pay for the treatnient. 



To illustrate the operation of the mill twenty-three specimens aro 

 shown. 



(1) General average of the ore as sent from the rock honse to tbe mill. (r)4273.) 



(2) Crushed rock, as it passes the sieves of the mortal". (r>l:il4.) 



(3) Heads from the mortar, consisting of metallic copper too large to pass the 

 sieves. (54229.) 



(4) First-class material, from the first division of the hydratilic separator. (54218.) 



(5) Second-class material, from the second division of the hydraulic separator. 

 (54219. ) 



(fi) Third-class material, from the third division of the hydraulic separator. 

 (54220.) 



(7) Fourth-class material, from the fourth division of the hydraulic separator. 

 (54221.) 



(8) Slimes, that pass away with the water from the hydraulic separator. (54222.) 



(9) No. 1 copper, separated on the roughing jigs. (54244.) 



(10) Ragging, consisting of particles of copper with small pieces of rock adhering 

 to it, scraped from the surface of the copper on the sieves. (54230.) 



(11) Tails, from the roughing jigs. (54223.) 



(12) Hutch work, from the roughing jigs treating first and second-class material 

 from the hydraulic separator, (54225.) 



(13) Hutchwork, from roughing jigs treating third and fourth class material from 

 the liydraulic separator. (.54227.) 



(14) No. 2 copper, separated on the finishing jigs. (.54245.) 



(15) Tails, from finishing jigs. (54224.) 



(IG) Slimes, as fed to Evans slime tables from settling boxes. (54228.) 

 ri7) Heads, from Evans slime tables. (54243.) 



(18) No. 3 copper, obtained in treating the heads from the Evans slime tables in 

 keeves. (5424G.) 



(19) No. 4 copper, obtained in treating the heads from the Evans slime tables in 

 keeves. (54247.) 



(20) Tails from Evans slime tables. (54226.) 



(21) Tails, taken from the runs of the tail house. (54231.) 



(22) No. 5 copper, obtained by treatment of the tails in the tail honse. (54248.) 



(23) Tails, froju the huddle in the tail house. (54232.) 



