DRESSING OF ORES 



99 



Order of fall. Centre head first, then right and left. 

 Number of Heads in a Battery. Three, at most five. 



Stamping Kesults. Weight of head, 250 Ibs., fall 8 inches, making 60 drops per 



minute, will produce, in 24 hours, 

 Stuff, 2 millimeters size . . - i . .30 cubic feet 



1 ' > .' . ' "." .16 



^ :;> . . . : . .0 



Cast-iron Bottoms Will afford 3 per cent, higher result than can bo obtained from a 



stone bottom. 

 Water, per minute, per head : 



For direct discharge , . . . 3 to 5 gallons. 



Large stuff, 4 to 8 millimeters . . .12 gallons. 



Kough 2 4 ... . 6 



,, Fine 1 2 -, ,. .3 



Space between head and inside of battery box 1 to 1 inch, except at the side at 

 which the stuff is introduced, where it is 2 to 3 inches. 



Some years ago the late P. Eitter von Rittinger contrived a battery box for 

 stamping under water, fig. 675. a, cast-iron bottom wedged into the box ; b, stamp 



675 



screen set 1^ to 3 inches above the bottom; c, water-tight panel, made of strong 

 boards fixed within a short distance from the front of battery box, the opening d ex- 

 tending several inches below the anvil of the battery ; e, outlet-pipe, in the centre, and 

 near to the lower edge of the panel. The bottom of the channel between the battery 

 box and panel is inclined from both sides towards the outlet e by means of strips of 

 timber inserted in the angles. The amount of discharge through the pipe e can be 

 regulated, and the pipe is so fixed, that the water rises, and is kept at such a level 

 above the stamp head, that the fall takes place entirely under water. At Schemnitz, 

 the duty obtained by the use of this battery box is said to be nearly 50 per cent, 

 greater than that obtained from the box previously in use. 



The feeding of the stamps is in some establishments effected by self -feeding hoppers, 

 in others by manual labour ; the batteries having, in the latter case, a small hopper 

 attached, into which the stuff is thrown with shovels. 



Fig. 676 is a set of stamping and washing works for the ores of argentiferous 

 galena, as mounted at Bockwiese, in the district of Zellerfeld, in the Hartz. 



A is the stamp mill and its subsidiary parts : among which are a, the driving or 

 main shaft ; 6, the overshot water-wheel ; c c, six strong rings or hoops of cast iron for 

 receiving each a cam or tappet ; g, the brake of the machine ; k k k, the three standards 

 of the stamps ; 1 1, &c., six pestles of pine wood, shod with lumps of cast iron. There 



H 2 



