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Testing of a Fragmentation System for a Hard Rock Mining Machine.
NTIS: PB/84-186394 Available for Reference At Bureau of Mines Libraries :78 pages
The purpose of this program was to develop deep-kerfing and core- breaking techniques to be incorporated into the design of a field prototype hard-rock mining machine. The machine is designed to mine nonabrasive bedded deposits up to 20,000 psi in uniaxial compressive strength. The mining technique involves cutting approximately 2-ft- deep parallel kerfs spaced 2 ft apart in either a horizontal or vertical direction and subsequently breaking out the cores as defined. The program was aimed at minimizing the required kerf width, obtaining reliable breaking within that kerf width, and determining cutter blade requirements necessary to achieve a mining rate of 20 ft3/min. Full-scale breaking and half-scale kerfing experiments were employed to evaluate the system. High-strength concrete test specimens were used to simulate the rock being cut and broken. The results indicate that the kerf-break technique can achieve the desired mining rate by utilizing two 7-ft-diam blades to cut 2-in-wide by 24-in-deep kerfs. A lateral load applied to the base of the kerf was selected at the core-breaking technique to be employed by the full-scale machine.
CP; Final Contract Report;
NTIS Accession No.
NTIS: PB/84-186394. Available for Reference At Bureau of Mines Libraries.