|Missouri University of Science and Technology
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"In the concentrating of lead ores, the water used in the mills carries the tailings from the jigs and tables to chatt tanks. Here the chatts and sands settle while the greater part of the water overflows and enters a sluice or slimes branch to the settling ponds. This overflow water carries with it a great deal of float lead. It is impossible to catch this lead in the mill on moving machinery without using too much power and mill space to effect a profitable saving. Ninety percent of this float will pass through a 140 mesh sieve. there will always be the largest percentage of this slimes lost in concentrating no matter how many tables or frue vanners are installed on a profitable working basis. coarse crushing in the mill lessens the bulk of slimes but increases the loss in the chatts, while on the other hand, finer crushing and classifying increases the slimes but decreases the loss in the chatts. It is my opinion after two years experience in milling, that the latter method increases the efficiency of the mill, thus lowering the total percentage of loss" – Introduction, p. .