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Comprehensive Ground Control Study of a Mechanized Longwall Operation - 2 Volume Set: Final Report - Volume 2.

NTIS: PB/262-476 Available for Reference At Bureau Libraries :270 pages
The objective of this study was to make strata control measurements on an operating longwall, from which engineering design values for structural parameters such as convergence in the face area and support load density, as function of the rate of mining and the strata properties, can be extracted. Instruments installed in the mine were borehole pressure cells, convergence recorders, horizontal roof strain indicaters, differential floor movement systems, and lateral roof and floor movement systems. Instruments installed on the surface, above the instrumented longwall panels, consisted of a slope indicator system, a vertical bed settlement probe system, and a shear displacement detecting system. A comprehensive surface subsidence study was conducted in conjunction with the instrumentation. In addition to the instrumentation and monitoring, special tests were conducted to determine the bearing capacity of the roof and floor rocks, in situ modulus of coal, roof and floor rocks, and response of borehole pressure cells to ground stress. This report describes the instrumentation work, special tests, and presents the data collected. Volume II contains four special reports: physical properties of coal and coal measure rocks, bearing capacity of roof and floor rocks, response of borehole pressure cells, and installation of subsurface instrumentation.
Publication Date
Document Type
CP; Final Contract Report;
Fiscal Year
NTIS Accession No.
NTIS Price
Identifying No.
OFR 5(2)-77
NIOSH Division
Source Name
NTIS: PB/262-476 Available for Reference At Bureau Libraries
Performing Organization
Harza Engineering Company
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division