A supplement to Ures Dictionary of Arts, Manufactures, and Mines, : containing a clear exposition of their principles and practice. . e and capable of a highdegree of enrichment, the slimes average 9 per cent., and are concentrated, by means ofthis apparatus, together with a round buddle and dolly tub, to 75 per cent, of metal. Withsix trunks, one round buddle, one man, and four boys, about nine tons of clean ore are ob-tained monthly. Attempts have been made by Brunton and others to separate metalliferous ores of dif-ferent specific gravities by allowing them to descend at regulated intervals
A supplement to Ures Dictionary of Arts, Manufactures, and Mines, : containing a clear exposition of their principles and practice. . e and capable of a highdegree of enrichment, the slimes average 9 per cent., and are concentrated, by means ofthis apparatus, together with a round buddle and dolly tub, to 75 per cent, of metal. Withsix trunks, one round buddle, one man, and four boys, about nine tons of clean ore are ob-tained monthly. Attempts have been made by Brunton and others to separate metalliferous ores of dif-ferent specific gravities by allowing them to descend at regulated intervals in still reversing the operation and causing the current to ascend uniformly, the particles mayhe- iTiich more conveniently and accurately classified. This has been done in a machine 870 OKES, DRESSING UF. designed by the late Mr. Herbert Mackworth. Suppose a funnel-shaped tube, larger at thetop; nitl) a current of considerable velocity flowing upwards through it, grains of equalsize of galena, pyrites, and quartz, when thrown in, will be suspended at ditierent heights, 1 11 <? 1 1 1i 1 1 mill 1 1 1 li ?\ I ! 1 U. 518 depending on the velocity of the current at each heiglit. Tlius culiical grains of galena,iron, pyrites, and quartz, of 12 inch diameter, will be just suspended by vertical currentsmoving at velocities of 12 inches, 7 inclies, and .i inches linear per second ; flat or oblongparticles require lathcr less velocities to support them, inasmuch as they descend moreslowly in still water than the cubical or spherical particles. A sinij)le form of applying this principle is presented by the vertical trunks shown in,^<7,! 519 and 520. Metalliferous ore, after being classified by .sifting, or tin ore as it comesfrom the stamps, may be allowed to flow mixed with water down the shoot a. The supply ORES, DRESSING OF. 871 of water should be taken from a head so as to be perfectly uniform in quantity. The watermixed with the ore flows in the direction of the arro
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Keywords: ., bookcentury1800, bookdecade1860, bookpublishernewyo, bookyear1864
