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Case study of shield-strata interaction at a southern Ohio mine.

Authors
Oyler-DC
Source
Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, RI 9534, 1995 Jan; :1-28
Link
NIOSHTIC No.
20039284
Abstract
The U.S. Bureau of Mines studied the interaction of longwall shield supports and adjacent strata at the Meigs No. 31 Mine in southeastern Ohio. Twenty-three legs of twenty shields at midface were instrumented with pressure transducers and monitored for 11 weeks. During the project, leg setting pressures were reduced twice to determine the effect of setting pressure on shield-strata interaction. No correlation was observed between setting pressure and leg loading rates. The shield loading profiles were consistent with a model of the roof consisting of two zones, a thin immediate roof loading the shields well below the typical setting force, and a main roof zone essentially supported by the coal and gob and loading shields through its convergence. This model was used to develop an equation for estimating loading rates at the site. The only variable of the equation is time and the equation consists of an exponential term to account for the immediate roof loading and a linear term to account for main roof loading. The equation gave good correlation with average loading rates, but the variation in loading from cycle to cycle was too great for the equation to give good predictions of individual cycle loading rates.
Keywords
Shields; Geologic-formations; Rock-mechanics; Loads-forces; Transducers; Regression-analysis; Geotechnical-engineering; Shielding; Cyclic-loading; Mining-equipment; Case-studies; Longwall-mining; Underground-mining; Tunneling; Mining-engineering; Mathematical-models
Publication Date
19950101
Document Type
Report of Investigations
Fiscal Year
1995
NTIS Accession No.
PB95-178901
NTIS Price
A03
Identifying No.
RI-9534
NIOSH Division
PRC
Source Name
Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, RI 9534
State
PA
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