110 



DRESSING OF ORES 



not seen in the end of tho lever r, traverses in the slot shown in the bridle rod imme- 

 diately below the bracket. The sieve measures 4x2 feet and 9 inches deep. It is 

 strengthened by iron bands and numerous slips across the bottom. 



The jigging apparatus, Jig. 685, was introduced some years since at Allenheads, 

 with satisfactory results. The larger and denser portion of stuff separated by this 

 apparatus is conveyed by suitable launders to a series of sieves, arranged on the top 

 of a conical reservoir, furnished with a feed pipe for the admission of water, and with 

 an outlet pipe at the bottom. This reservoir is placed within another reservoir, also, 

 in the form of an inverted cone, and provided with an outlet pipe at the lower part. A, 

 excentric giving motion to the sieve ; B, launder conveying stuff to such sieves ; c, dis- 

 tributor, either stationary or revolving as may bo required, delivering stuff to tho 

 sieves arranged on the top of the conical reservoir ; F, valve for discharging tho finer 

 portion of the ore ; G o, internal cistern furnished with an outlet valve H. 



The sieves have a slight outward inclination, and the refuse substances with tho 

 waste water are carried over and deposited in the conical cistern o G. 



The sieves should make from 150 to 200 pulsations per minute, according to the 

 quantity and character of the stuff under treatment. 



The following is the result of trials made on 160 tons of stuff, one half being de- 

 livered to this machine, the other to the common jigging hutch : 



Produce. 



Pctherictts Separator. Figs. 686 and G87. A, the plunger or force-pump ; B, re- 

 cf.jitack-s fitted with sieves; c, hufcch filled with water; D, discharge holes fitted with 

 wooden plugs ; E, moveable plate to admit of withdrawing tho ore ; F, hopper with 

 shoots for supplying sieves ; H, beam for giving motion to plunger piston A; J, laun- 

 der for delivering water to hutch. 



About the year 1831, Mr. Pethorick introduced tho above machine at tho Fowey 

 Consols Mines, in Cornwall. It. was described in the ' Quarterly Mining Keview,' 

 January 1832: from which the following is extracted: 'This machinery is par- 



