Analysis of longwall pillar stability
This dissertation proposes a new method for longwall pillar design, developed primarily from underground measurements. This dissertation addresses three areas of direct relevance to longwall pillar design: (1) The magnitude, time-of-arrival, and distribution of the abutment loads applied to longwall pillars; (2) The strength and behavior of coal pillars; (3) The relationship between pillar sizing and entry stability, and other factors affecting the roof/pillar/floor interaction during longwall mining. The research focused on two field studies performed in adjacent longwall panels at a West Virginia coal mine. In each study, measurements of pillar stress, pillar deformation, and entry stability were obtained during and after the approach of the longwall face. Other research included detailed reanalyses of field data from other studies, an in-depth comparative study of available longwall pillar design methods, numerical modeling to determine post-development longwall pillar loads, and an evaluation of two index tests used to determine coal strength. The proposed longwall pillar design method incorporates a new approach to estimating abutment loads hat was developed from the research. The method also employs existing empirical pillar strength formulas that were shown to be applicable to longwall pillars. The proposed design method represents an improvement over the existing methods, because it can be used with designs employing combinations of differently sized pillars, and because it can calculate stability factors for the several different service functions of pillars around a longwall.
- Research Organization:
- Pennsylvania State Univ., University Park (USA)
- OSTI ID:
- 6182534
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
012031* -- Coal
Lignite
& Peat-- Underground Mining-- Strata Mechanics & Control-- (1987-)
APPALACHIA
CALCULATION METHODS
CARBONACEOUS MATERIALS
COAL
COAL DEPOSITS
COAL MINING
COAL SEAMS
DEFORMATION
DESIGN
ENERGY SOURCES
FEDERAL REGION III
FLOORS
FOSSIL FUELS
FUELS
GEOLOGIC DEPOSITS
LONGWALL MINING
MATERIALS
MATHEMATICAL MODELS
MECHANICAL PROPERTIES
MINERAL RESOURCES
MINING
NORTH AMERICA
RESOURCES
ROOFS
SIZING
STABILITY
STATIC LOADS
STRATA CONTROL
STRESS ANALYSIS
SUPPORT PILLARS
UNDERGROUND MINING
USA
WEST VIRGINIA
WORKING FACES