DRESSING OF ORES 



135 



a hopper A, and falls into the basin B. The slime from this basin flows freely over 

 the convex plate E i/. It will appear that this arrangement secures an uniform distri- 

 bution of the stuff, and at the same time the heavier portion is concentrated with 

 greater rapidity than can be accomplished by means of the common rotating buddle. 



The diameter of the hopper from G to H is 12 inches, from j to K 6 inches ; the 

 basin from c to D is 9 inches diameter, and the conical centre from F to F' is 7 feet 

 diameter. The buddle bottom is covered with plank in the usual way. Its diameter 

 is 25 feet, with an annular ditch or gullet 12 inches wide. Into this gullet the sterile 

 sand is scraped ; and if the nature of the ground will admit, the bottom of the gullet 

 may be sufficiently inclined to scour away the stuff, by the action of a stream of water. 

 Captain Josiah Thomas states that the inclination of the buddle floor at Dolcoath 

 varies from 1 inch to an inch in the foot ; viz. for working ' roughs ' 1 inch, for 

 slimes 1 inch, ~for treating stamps work, % an inch. The diameter of the wood centre 

 F F', also varies from 7 to 10 feet diameter. Mr. J. M. Pike, of Camborne, has 

 furnished the following dimensions of a buddle erected at Tincroft : 



Floor of buddle, 20 feet diameter. 



Inclination of floor of buddle, | of an inch in a foot. 



Wood cone, 9 feet diameter, depth 15 inches. 



Number of arms in buddle, 6. 



Height of arms from wood cone, 7 inches. 



Speed of distributing plate, 2 revolutions per minute. 



Buddie, 21 feet diameter, filled in 24 hours to a depth of 13 inches. Contents 128 

 cubic feet, or o cubic feet per hour, requiring 1,080 gallons of water, or 204 gallons 

 per cubic foot of stuff treated. 



The transverse section, fig. 730, shows the application of these buddies to the 



730 



enrichment of tin ores. A, stamps pass ; B, framework of stamps ; c, stamps platform ; 

 D, launder for conveying stamp work to buddies E and F. Between the respective 

 buddies runs a gullet, o, into which the waste flows, when the flushets, H H, are 

 opened. The bed of each buddle is 20 feet in diameter, the annular spaces 1 1, one 

 foot wide, making the distance from wall to wall 22 feet. It will be observed that 

 the annular space is inclined towards the gullet, G. One buddle is sufficient to treat 

 the stuff pulverised by a set of twelve or sixteen stamp-heads. 



The inclination of the buddle bottom is \ of an inch per foot. Motion is given to 

 the centre plate and arms by means of bevil gearing, moved by the stamping engine. 

 The distributing plate of the buddle makes 2.} revolutions per minute. The stamp- 

 work, when passed through a perforated plate, having 36 holes to the lineal inch, can 

 be concentrated at the rate of 5 cubic feet per hour. 



Slime Buddie. This machine, fig. 731, is said to effect the separation of the earthy 

 matters from finely-divided ores more readily than the ordinary round buddle. For 

 this purpose the pulverised ore is introduced near the centre of a large slightly 

 conical rotating table, and flowing towards its periphery a portion of the upper 

 part or head becomes at once freed from extraneous substances. Beyond this line of 

 separation in the direction of the circumference, the stuff is subjected to the action 

 of a series of brushes or rakes, and by means of a sheet of water flowing over the 

 agitated slimes, clean ore is stated to be produced almost at a single operation. 



The illustration,/^. 731, represents this machine at first erected at Clausthal. but 

 it may be remarked that some of its mechanical details have been since judiciously 

 modified by Mr. Zenner. A is an axis .supporting and giving motion to the table B, 

 16 feet in diameter, and rising towards the centre 1 inch per foot; c, cast-iron 

 wheel, 15 inches in diameter, operated on by the screw i>. The tooth-wheel F 

 drives the pinion f, the axis of which is provided with a crank giving motion to a 

 rod fitted with brushes; G is an annular receiving box, 4i inches wide and 6 inches 

 deep ; a, circular trough of sheet iron supported on the axis of the table an inch or 



