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The Desensitization and Malfunction of Coal-mine Explosives.

Authors
Wieland-MS
Source
Proc 13th Conf on Explosives and Blasting Practices Miami Florida 1987 Feb; :97-114
Link
NIOSHTIC No.
10005944
Abstract
This paper indicates that underground coal-mine explosives can be substantially degraded by the underground stress waves from the explosion of neighboring borehole charges. This cross-borehole interaction generally yields the worst receptor charge performance when the borehole separations are too close. For explosives which recover, the receptor degradation is worst when the delay until firing is small. Except for a poor quality muck pile or unreacted cartridge fragments, degraded charge malfunctions of this type are difficult to detect in coal-mine delay blasting. A simulator which reproduces the underground wave/receptor charge interaction and special underwater donor/receptor tests were utilized to study this transient desensitization problem. Test results revealed reductions in receptor energy output, delayed transitions into detonation, inferior reaction rates, or sympathetic reaction responses from the impaction. Tests on detonators showed reduced tip-strength, abnormal functioning times, or sympathetic firing as a result of transient impaction. The cross-borehole desensitization and sympathetic reaction response problems warrant concern because they are logical mechanisms for raising the risk of hazardous mining conditions, including blown-out shots, flyrock, charge deflagration, and methane/coal dust ignitions.
Publication Date
19870201
Document Type
OP;
Fiscal Year
1987
NTIS Accession No.
NTIS Price
Identifying No.
OP 68-88
NIOSH Division
PRC;
Source Name
Proc. 13th Conf. on Explosives and Blasting Practices, Miami, Florida, Feb. 1-6, 1987, PP. 97-114
State
FL;
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