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Overbreak Control in the White Pine Underground Mine.

Authors
Fletcher-LR; Plis-MN; Stachura-VJ
Source
Paper in Proceedings of the 15th Conf on Explosives & Blasting Tech New Orleans Louisiana 1989 :11 pages
Link
NIOSHTIC No.
10007512
Abstract
Falls of ground remain a leading cause of fatalities and injuries in underground mines. In response to this situation, the Bureau of Mines conducted a series of experiments in the White Pine room-and- pillar copper mine that resulted in smoother, safer ribs due to a reduction in the amount of overbreak caused by blasting. The tests evaluated the effects of changes in the loading of the rib holes of the mine's 20-by 28-ft drift round driven in shale and sandstone. The relative integrity of the ribs remaining after the blasts was measured using both photographic and seismic rrefraction techniques. Four variations of the mine's standard blast design were examined. Comparisons were made between rounds with rib holes having fully coupled and decoupled powder columns that were initiated by millisecond- and half-second-delay caps. The results showed that the smoothest and most stable ribs were produced by rounds whose rib holes had decoupled powder columns initiated by millisecond-delay caps.
Publication Date
19890101
Document Type
OP;
Fiscal Year
1989
NTIS Accession No.
NTIS Price
Identifying No.
OP 37-90
NIOSH Division
TCRC;
Source Name
Paper in Proceedings of the 15th Conf. on Explosives & Blasting Tech., New Orleans, Louisiana 1989
State
LA;
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