134 



DRESSING OF ORES 



It would -bo found a great improvement if these buddies were arranged so as to have 

 thoir bottoms elevated when it might bo necessary. As they are fitted at present the 

 angle at the head is a constantly increasing one. The result is, the heads become 

 poorer and tho_ tails richer, as the operation proceeds, provided, the fixed inclination 

 of the buddle is correct at starting. In proportion to the poorness of the stuff tin-. 

 buddle should have its width increased, as well as be made shallower. If the stuff bo 

 also passed through a trommel before entering the buddle, the result will bo found 

 much improved. 



Round Buddie. This machine serves to separate particles of unequal specific gravity 

 iu a circular space inclined from the centre towards the circumference. Its construc- 

 tion will be best understood by reference to fig. 728 ; in which A is the conical floor, 



728 



formed of wood, and about 18 feet in diameter, on which the stuff is distributed ; B is 

 a cone, supporting the upper part of the apparatus, and serving to effect the equal dis- 

 tribution of the orey matter. D, wheel for giving motion to the arrangement ; E, a funnel, 

 perforated with four holes and furnished at top with an annular trough ; F F are arms, 

 carrying two brushes balanced by the weights GO; H is a launder, for conducting the 

 stuff from the pit i ; it is a receptacle in which the slimes mixed with water are 

 worked up in suspension by the tormentor, which is a wooden cylinder provided with 

 a number of iron spikes ; L is a pulley taking its motion from a water-wheel, and M a 

 circular sieve fixed on the arbor N. The stuff at K is gradually worked over a bridge 

 forming one of the sides of a catch pit between the sieve M and the tormentor, from 

 whence it passes off into the sieve by which the finer particles are strained into the 

 pit i, whilst the coarser, together with chips and other like substances, are dis- 

 charged on the inclined floor in connection with the launder o. From the pit i the 

 stuff flows by the launder H into the funnel E, and after passing through the perfora- 

 tions flows over the surface of the fixed cone B, and from thence towards the circum- 

 ference, leaving in its progress the heavier portions of its constituents, whilst the 

 surface is constantly swept smooth by means of the revolving brushes. By this moans 

 the particles of different densities will be found arranged in consecutive circles. The 

 arms usually make from two and a half to four revolutions per minute, and a machine 

 having a bed 18 feet in diameter will work up from 15 to 20 tons of stuff per day of 

 1 hours. 



In the ordinary round buddle the stuff is somewhat unevenly distributed, as well as 

 imperfectly separated. This arises from the small diameter of the cone at its base, 

 and the large volume of water and slime discharged upon its limited surface. These 

 objections are to a certain extent removed by an improved round buddle, fig. 729. 



729 



After the stuff has passed through a revolving trommel or grating connected with the 

 apparatus, and to a certain extent sized, it is conveyed, by means of a launder, into 



