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Mining Publication: Bolt Load Changes During Initial Face Advance and Cross-Cut Breakthrough

NOTE: This page is archived for historical purposes and is no longer being maintained or updated. Contact NIOSH Mining if you need an accessible version.

Original creation date: August 2004

Image of publication Bolt Load Changes During Initial Face Advance and Cross-Cut Breakthrough

The San Juan Mine and the National Institute for Occupational Safety and Health conducted a study to measure how development mining affected bolt loads. Twelve fully grouted, instrumented roof bolts were installed at two three-way intersections as part of the standard bolting pattern. Newly developed miniature data acquisition systems (MIDAS) were used to measure bolt load changes during initial face advance and cross-cut breakthrough. The effects of cut placement and depth on roof bolt loads were studied. This test showed how bolt loads increased at five positions along the bolt length during initial mining. Both entry advance and crosscut breakthrough produced a similar percentage of increase in bolt loads. Geologic differences between the test sites were probably responsible for the differences in amounts of bolt loading. The test site with more top coal and a higher rock quality designation (RQD) had lower bolt loads.

Authors: SP Signer, J Pile, S Bessinger

Conference Paper - August 2004

NIOSHTIC2 Number: 20026117

Proceedings of the 23rd International Conference on Ground Control in Mining, Morgantown, West Virginia, August 3-5, 2004, S.S. Peng, C. Mark, G. Finfinger, S. Tadolini, A.W. Khair, and K. Heasley, eds., Morgantown, WV: West Virginia University, 2004 Aug; :250-257