466 Macfarlane on the Acton Copyer Mine, 



crush ore, after having been spalled down, and separated from 

 the waste rock, assays from three to five per cent. It is further 

 ti-eated by crushing and jigging. The so-called fourths consist 

 of limestone containing copper pyrites in coarse grains, small 

 strings and finely disseminated particles. This quality is not 

 worked up at present. It is piled in separate heaps, in order 

 to be treated by stamping and washing, so soon as the appa- 

 ratus for that purpose is procured. Besides the coarser rock, 

 there is produced, in the various workings, smalls, which consist of 

 pieces of ore and rock whose diameter does not exceed three or four 

 inches, and which are usually so coated with mud as not to be 

 easily separable from each other. These smalls are first thrown 

 upon a screen, the bars of which are one and a quarter inches apart; 

 the larger pieces which remain upon it are sorted and spalled in the 

 same way as the coarser rock ; while the smaller pieces, which pass 

 through, and assay from two to three per cent, are at once sub- 

 jected to crushing and jigging. 



The crush ore, and the finer part of the smalls, are reduced, 

 by passing between cast iron rollers, to such a size as to pass 

 through a sieve of twelve holes to a square inch. The crushed 

 product is then brought into a jigging sieve, having sixty-four 

 holes to a square inch. This sieve is wholly immersed in water, 

 where it receives a succession of jerks, each of which causes it to 

 descend, and suspends its contents in the water. These then 

 arrange themselves according to their relative specific gravities ; 

 the richest and largest particles at the bottom of the sieve, the 

 poorest and smallest at the top. After the sieve has received 

 a sufiicient number of jerks, it is raised out of the water, 

 and the upper layer, or skimmings, scraped off". These contain 

 from one and a-half to two per cent copper, and are thrown aside. 

 That part which collects at the bottom of the sieve, and contains 

 twelve to fourteen per cent of copper, is called ragging, and is a 

 marketable product. There is sometimes produced au intermediate 

 sort called seconds, occupying a position on the sieve between the 

 skimmino-s and the ragging. This is laid apart, and afterwards re- 

 jigged, the same products being produced as those above mentioned. 

 In this process of jigging a considerable portion, the finest part of 

 the crush work, falls through the sieve into the box below, which 

 contains the water, and is called hutch-work. This, on being 

 washed in a streak from the slime which it contains, assays from 



