84 DRESSING OF ORES 



water ty means of pipes, open launders are equally efficient. The trommels may be 

 placed side by side, or run end-ways, and be driven by moans of spur wheels or by a 

 light chain crossed on the pulleys. 



659 



GRINDING AND CRUSHING MACHINEBY. 



In small mines, Bucking, fig. 660, is resorted to, instead of employing the crushing 

 mill. This operation consists of pounding pieces of mixed ore on a slab of iron A, by 

 means of a hammer or bucker B. The wall on which the plate A is placed, is about 

 3 feet high. The stuff to be pounded is placed behind the slab, and is drawn upon 

 and swept off the plate by the left hand. In Cornwall it is customary to keep time 

 with the blows and to stand to the bench but in Derbyshire each operator works 

 independently, and is usually seated. 



661 



The bucker, /#. 661, is formed of a wrought-iron steel-faced plate A, 3 inches 

 square, with a socket B, for receiving a wooden handle c. Its cost is about Is. 4d. 



The reduction of vein-stone to a suitable size, so as to extract a maximum quantity 

 of ore is a matter of considerable importance. The class of machinery to bo employed 

 must depend upon the normal constituents of tho stone. 



