126 



DRESSING OF ORES 



which prevents the fine and light particles from passing in tho same direction.' A, 

 fig. 710, inlet of clean water; B, launder delivering tho orcy matter; c outlet of fino 



710 



and inferior stuff; D, discharge orifice for rough and heavy stuff. This operation 

 must bo regulated by a slide. A cistern, 10 feet square on the top and 18 inches 

 deep, will pass through about 40 tons in 10 hours. When separating stamps work, 

 a smaller cistern is employed, say about 14 inches square, 10 inches deep, this will 

 despatch 6 tons in 10 hours. 



A valuable form of classifier is shown in^. 711, the peculiarity of which consists 



in the manner of introducing the water and slimes. Instead of the latter depending 

 for separation upon tho power of an ascending column of water, it here passes into a 

 horizontal flow of greater or less volume and velocity, produced by altering the tap o. 

 Compartments, viz. 1, 2, 3, and 4, are also fitted in tho box, for tho purpose of receiving 

 mjneral of different densities and size, which is discharged and washed in strips set 

 underneath ; A, inlet launder to trommel ; c, trommel either of perforated plato, or 

 wire gauze ; D, shoot from trommel, serving to convoy away tho rougher portions. 

 E, hopper for conveying stuff to shoot ir, and from thence into tho box ; F, ascending 

 column of water ; o, tap for regulating tho flow of water; K, L, M, N, outlet pipes for 

 delivering tho separated stuff to strips or buddies; o, launder for receiving overflow 

 from cistern ; p, Q, n, weirs regulating tho length of the compartments, also for tho 

 purpose of effecting the disposition of tho different minerals with which the ore may 

 be associated. 



Horizontal Classifier. This classifier, shown in longitudinal elevation fig. 712, plan 

 fig. 713, and end elevation^. 714, is frequently employed at load and blende mines in 

 Germany, and is known in some of tho mines in this country. In many instances it is 

 built of wrought and cast iron ; but it may be equally well made in wood, and will cost 

 much less. The slimey water is introduced at tho narrow end; tho heaviest equivalents 

 fall into the first compartment, a ; equivalents of tho second degree into the second, ft; 



