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New closure rate instruments for retreat mining operations.

Authors
McVey-JR; Howie-WL
Source
Min Eng 1981 Dec; 33(12):1699-1700
NIOSHTIC No.
10002276
Abstract
The Bureau of Mines Spokane Research Center has constructed an intrinsically safe closure-rate instrument that provides the mine operator a means for predicting an imminent roof fall during pillar robbing. This improves operator and machine safety and prevents delays in digging out equipment. The instrument system consists of two rugged retrievable extensometers connected by long electrical cables to a digital readout unit for reading closure and closure rate. Once a predesignated closure rate is reached, the extensometer is retrieved by pulling it from the imminent roof fall area by the electrical cable. The equipment and mine personnel are also pulled back to await the fall, which usually occurs within minutes after the designated rate is reached. Although the unit is primarily designed for retreat mining operations, it can be used for any activity requiring measurement of displacement or rate of displacement with a measurement range of zero to 6 inches with 0.1 percent accuracy for openings 4 1/2 to 12 feet.
Keywords
Mining-industry; Rock-mechanics; Rock-falls; Geology; Retreat-mining; Underground-mining; Monitors; Monitoring-systems
CODEN
MIENAB
Publication Date
19811201
Document Type
OP; Journal Article
Fiscal Year
1982
NTIS Accession No.
NTIS Price
Identifying No.
OP 8-82
Issue of Publication
12
ISSN
0026-5187
NIOSH Division
SRC
Source Name
Mining Engineering
State
WA
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