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Flexible roof drill for low coal.
Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, Contract C-11205, 1982 Jan; :1-30
Contract number DE-AC22-74ET11205 provided for the continued testing of a flexible roof drill system which allows the operator to drill roof bolt holes longer than seam height. The system was mounted on a modified Fletcher LTDO bolting machine. The objective of the contract is to establish the reliability of the flexible drill from extended life testing in an operating coal mine and by laboratory life testing. The reliability goal is 1000 mean-holes-between-failures. The underground test was conducted in the GEX-Colorado, Incorporated, Roadside Mine in Palisade, Colorado. The underground test concluded with the drilling for and installation of 12,361 four-foot roof bolts. The laboratory test consisted of the simulated drilling of 20,000 eight-foot long holes. The reliability goal was achieved with an associated confidence level greater than 99%.
Roof bolts; Drilling equipment; Coal mining; Underground mining; Installation; Performance testing; Reliability; Coal seams; Thickness; Mining equipment; Recommendations
CP; Final Contract Report
NTIS Accession No.
Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, Contract C-11205
CO; DC; PA