Disc Cutting of Low-strength Brittle Rock
Disc cutters are designed to fragment hard, brittle rock (UCS 60-200 MPa). The most energy-efficient mechanism requires the cutter to penetrate the rock to the critical depth required to initiate chipping. In hard, brittle rock the critical depth is relatively shallow (less than 13 mm); deeper penetrations are difficult to achieve reliably. Using disc cutters in very soft rock results in plowing rather than chipping. However the intermediate class - brittle enough to chip yet weak enough for deep penetration - has not been fully explored. This paper reports on a series of laboratory tests in which a 292mm-diameter constant cross-section disc cutter was applied to a soft limestone (UCS 14.2 MPa) and a weakly cemented sandstone (UCS 25.5 MPa) at ratios of cut spacing to cutter penetration (S/P) from 6 to 36. Snowdon et al.  predict optimal fragmentation at S/P ratios of one to five for rock in this strength range; although modern practice tends toward higher ratios, little data is available for high-S/P ratio, deep-penetration cutting of low-strength rocks. Cutting tests completed to date indicate that deep penetration coupled with wide spacing at moderate S/P ratios may be more effective in the rocks tested Copy; 2006, ARMA, American Rock Mechanics Association.
L. S. Gertsch and D. A. Summers, "Disc Cutting of Low-strength Brittle Rock," Proceedings of the 41st U.S. Rock Mechanics Symposium - ARMA's Golden Rocks 2006 - 50 Years of Rock Mechanics, American Rock Mechanics Association (ARMA), Jan 2006.
41st U.S. Rock Mechanics Symposium - ARMA's Golden Rocks 2006 - 50 Years of Rock Mechanics
Geosciences and Geological and Petroleum Engineering
Mining and Nuclear Engineering
American Rock Mechanics Association
Article - Conference proceedings
© 2006 American Rock Mechanics Association (ARMA), All rights reserved.
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