ICGCM Papers:
Fundamental Research Studies
 
 
Structural Geological and Stress Controls on Natural Gas Inrushes in Southern West Virginia Longwall Coal Mines
35th International Conference on Ground Control in Mining
Structural Geological and Stress Controls on Natural Gas Inrushes in Southern West Virginia Longwall Coal Mines
by
Sandin E Phillipson, MSHA - Pittsburgh Safety and Health Technology Center, Pittsburgh, United States
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[Conference] 35th International Conference on Ground Control in Mining
[Price] Free  [Comments] 0
[Topical Area] Fundamental Research Studies
[Author] Sandin E Phillipson, MSHA - Pittsburgh Safety and Health Technology Center, Pittsburgh, United States
[Abstract] 
Key Conclusions:
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Floor gas is trapped in pre-existing geologic structures, which dilate and release gas when longwall mining relieves confinement stress. These geologic structures can be mapped and projected to predict where future outbursts might occur. Potential outburst areas can be avoided or pre-emptively hydro-fractured, and enhanced ventilation and dust control measures implemented to avoid fractional ignitions.
Key Findings:
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Gas involved in floor gas inrushes contains heavier hydrocarbons and different isotopes that distinguish it from standard coalbed methane, and indicate an organic shale source. Floor gas inrushes occur in the Eagle and Pocahontas No. 3 Seams of southern West Virginia. The inrushes occur at depths over 1,000 feet, and are associated with geologic structures such as faults and joints, and also occur when gob length is equal to face width.
Objective of the Paper:
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This paper will use the results of gas inrush investigations to propose a geologic model that explains the controls on floor gas inrushes so that mine operators can reduce their likelihood or mitigate their effects.
Problem Statement:
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Floor gas inrushes at longwall mines in southern West Virginia have resulted in disruption to mining, and represent a safety hazard that is poorly understood.