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The forgotten denominator: Pillar loading.

Authors
Heasley-KA
Source
Pacific rocks 2000: rock around the rim--proceedings of the Fourth North American Rock Mechanics Symposium, NARMS 2000, Seattle Washington, July 31-August 3, 2000. Girard JM, Leibman M, Breeds C, Doe T, eds. Brookfield, VT: A.A. Balkema, 2000 Jul; :457-464
Link
NIOSHTIC No.
20023676
Abstract
In the last few decades, a considerable amount of effort was directed at accurately determining the coal/pillar strength to use for safety designing coal mines. The outcome of this early work was the well known Obert-Duvall, Holland-Gaddy, Bieniawski, and Salamon-Munro equations for coal pillar strength. All of these equations were developed for, and were calibrated with, pillars in a large room-and-pillar area such that the loading could be determined using the "tributary-area" theory. In order to account for the abutment loads associated with full-extraction mining, the empirical methods have typically adopted a simple conceptualization of the abutment load through the use of an "abutment angle." Short of a complete numerical or analytical analysis of the coal seam and surrounding strata, very little work has been directed toward refining the empirical analysis of pillar loading. It appears that the vast majority of the research has been directed at determining the pillar strength, the numerator of the safety factor equation, when the denominator of the safety factor equation, the pillar loading, plays an equally important role in pillar design. This paper will address the deficit of pillar loading research by exploring the accuracy of the empirical abutment load calculations using insight provided by an elastic overburden model, a laminated overburden model and field observations. Ultimately, it is determined that a constant abutment angle probably over-predicts the abutment load as the mining depth increases.
Keywords
Mining-industry; Underground-mining; Coal-mining; Room-and-pillar-mining; Rock-mechanics; Geology
Publication Date
20000101
Document Type
Conference/Symposia Proceedings
Editors
Girard-JM; Leibman-M; Breeds-C; Doe-T
Fiscal Year
2000
NTIS Accession No.
NTIS Price
ISBN No.
9789058091550
NIOSH Division
PRL
Source Name
Pacific rocks 2000: rock around the rim--proceedings of the Fourth North American Rock Mechanics Symposium, NARMS 2000, Seattle Washington, July 31-August 3, 2000
State
PA; WA
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