A supplement to Ures Dictionary of Arts, Manufactures, and Mines, : containing a clear exposition of their principles and practice. . ying the stuff to be sifted ; s s bottom of sieves are lifted by the rod /, and make from 40 to 50 beats per minute. The sievesare set about eight inches apart, and discharge the stuff upon the inclines p p p. The holes in No. 1 sieve are ^ inch t 3 The apparatus is employed in the Clausthal Valley. Fig. 479 represents the trommel or sizing sieves in operation at the Devon Great Con-sols. Although the yield of ore at these mines is extre
A supplement to Ures Dictionary of Arts, Manufactures, and Mines, : containing a clear exposition of their principles and practice. . ying the stuff to be sifted ; s s bottom of sieves are lifted by the rod /, and make from 40 to 50 beats per minute. The sievesare set about eight inches apart, and discharge the stuff upon the inclines p p p. The holes in No. 1 sieve are ^ inch t 3 The apparatus is employed in the Clausthal Valley. Fig. 479 represents the trommel or sizing sieves in operation at the Devon Great Con-sols. Although the yield of ore at these mines is extremely large, it may not be generallyknown that nmch of it is obtained from stuff yielding no more than from f to H i)er cent,of metal. The product of the lode on arriving at the surface is cobbed and divided intotwo classes, the first going to market without further elaboration, whilst the dradge or infe-rior portion is treated l)y various processes of washing. The whole is however crushed tosuch a degree of fineness as to pass through the followiug_ holes:— ORES, DRESSING a, boles /ao inch diameter. ) hi C, Vio 845. ? .^^^\«^ rli. Jil!.*T,™ n ^ t^^^ - ^ ^^*^^ d^™^^*^- »t tf^^ •Kc end, and 18 inches%1%1 suterS .^ ^^^*°^ P^^ ™^^ ^^ ^^^sther affording ante 846 ORES, DRESSING JIachixery. Various crushing machines are described under Grinding and Crushing Machinery ;but it may be observed that this section of the dressing department deserves careful attention,as the results are more or less atiected according to the mode of working and adjusting thisclass of machinery. The crusher is, as it were, the starting or radiating point for treatingthe dradge work, and if considerable care is not exercised hero, not only will there be muchloss of power, but also of the initial quantity of ore. In the mining districts of this coun-try it is usual to introduce rough and fine dradge together; no preliminary division of thestuff is attempted ; the hopper is co
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Keywords: ., bookcentury1800, bookdecade1860, bookpublishernewyo, bookyear1864
