Evaluation of an Alternative Longwall Gate Road Design

摘要

This U.S. Bureau of Mines report describes the results from an in-mineinvestigation of an alternative longwall gate road design. The coal mine operator modified the pillar layout (reversed the location of the big and small pillars) in a portion of a three-entry longwall gate road area. The modified pillar layout was an attempt to reduce stress and, subsequently, stress-related ground control problems (cutter roof and dynamic floor heave events) in the tailgate region during second-panel mining. The results from borehole pressure cells (BPC's) installed in the modified gate road area showed that the ground pressures in the panel edge and adjacent small pillar were significantly reduced during second-panel mining compared to ground pressures experienced in the typical pillar layout gate road areas. The reduced stress levels around the tailgate entry adjacent to the second panel, as compared to the tailgate stress levels with the typical pillar arrangement, contributed to improved tailgate ground conditions in the test pillar zone.