Bulletin . leading to a grizzly. This grizzly consists of iron bars, usuallyheavy rails, spaced 4 to 5 inches apart as shown in Plate XIII, mineralized lumps in the oversize caught on the grizzly arebroken with sledge hammers into pieces smaU enough to pass through;the bowlders that are practically barren are sorted by hand andtrammed to the waste-rock pile. The proportion of waste rockthus sorted out varies from a fraction of 1 per cent to 15 per cent,according to the character of the ore. The sorting is done by screen-men, better known locally as/cull men. Sorting other than that by th
Bulletin . leading to a grizzly. This grizzly consists of iron bars, usuallyheavy rails, spaced 4 to 5 inches apart as shown in Plate XIII, mineralized lumps in the oversize caught on the grizzly arebroken with sledge hammers into pieces smaU enough to pass through;the bowlders that are practically barren are sorted by hand andtrammed to the waste-rock pile. The proportion of waste rockthus sorted out varies from a fraction of 1 per cent to 15 per cent,according to the character of the ore. The sorting is done by screen-men, better known locally as/cull men. Sorting other than that by the screenmen is rarely practiced atthe mines of the Joplin district. It is believed that sortmg out thegreater proportion of the large bowlders of waste rock from the oreis of much importance if properly done. The reasons for this beliefare perfectly clear. Eliminating a certain amount of waste rockincreases the richness of the material retained for further treatment BUREAU OF MINES BULLETIN 15« PLATE XIII. A. METHOD OF DUMPING TUB ON GRIZZLY ABOVE HOPPER.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectminesandmineralresou
