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Testing modified coal-cutting bit designs for reduced energy, dust, and incendivity.
Minneapolis, MN: U.S. Department of the Interior, Bureau of Mines, RI 8801, 1983 Jan; :1-31
Four bit designs, two conical and two radial, were tested in coal against a 60 deg. Conical reference bit to obtain data on orthogonal cutting forces and primary respirable dust generation. One conical and one radial design were modified by the Bureau of Mines for these tests. Results were mixed: one radial bit used substantially lower overall cutting forces and specific energy than the other bits and was the only cutter lower on energy and most forces than the standard 60 deg. Bit. However, it generated more specific and total dust than any other bit. The four bits were also tested for incendivity, with a 90 deg. Plumb-bob bit as the reference. The frictional ignition tests were designated to simulate both trimming top rock and cutting such rock during advance on-sump. Results of these tests were also mixed. The radial bits were substantially less incendive than the reference bit and caused no ignitions in either top trimming or sump modes. Only the modified mushroom- tipped conical bit caused ignitions. Bits similar to this modified design should not be used on drum-type miners in gassy mine areas; instead, the other types of bits tested should be used to reduce ignition potential to a minimum.
Coal-mining; Mining-equipment; Dust-control; Cutting-tools; Drag-bits; Geometric-forms; Friction-factor; Ignition; Dust-explosions; Mine-safety; Mining-industry
IH; Report of Investigations
NTIS Accession No.
Minneapolis, MN: U.S. Department of the Interior, Bureau of Mines, RI 8801
Page last reviewed: May 5, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division