RI 9184 - Effects of Various Longwall Chain Pillar Configurations on Gate Road Stability

The Bureau of Mines conducted a field study to assess the performance of various chain pillar configurations in terms of gate road entry sta-bility. Vibrating wire stressmeters (VWS's) were installed in four consecutive gate road chain pillars. Field data collected during panel retreat were analyzed to gain a better understanding of the mechanics of vertical load redistribution in gate road chain pillars as it relates to ground control problems. Several different pillar configurations were investigated including abutment-yield and yield-abutment-yield designs. VWS data indicate that average pillar loads were lower and appeared abutment-yield pillar arrangement was utilized. port the occurrence of severe roof and pillar to stabilize when an Data analyses also supdeterioration that was visually observed in the tailgate entries during panel extraction.