Changes in Cross-Sectional Area of Gateroads in Longwalls with Roof Caving, Ventilated with “U” and “Y” Systems

摘要

Content: In the paper results of measurements of underground gateroad deformations are presented. The measurements were conducted in seven collieries in the Upper Silesian Coal Basin. Altogether 28 gateroads were analysed:12 longwalls with ?Y“ and 4 longwalls with ?U“ ventilation system. Based on results of measurements, changes in cross-sectional area of gateroads were calculated and then referred to their original dimensions (when they were developed). Values of cross-sectional area of gateroads in front of and behind the longwall face are presented. Differences in deformation of gateroads in longwalls with the “U” ventilation system, surrounded by unmined coal, and/or goaf on one side were determined. Changes in cross-sectional area of reused gateroads, and newly driven ones (with a coal pillar separating the goaf from the working), were estimated. For gateroads of the longwalls with “Y” ventilation system their deformations at a distance of 200 metres behind the longwall face was determined. For selected gateroads their convergence was calculated with numerical modeling and a method developed at GIG. Calculations were made with Phase2 software based on the finite element method (FEM). Accuracy of forecasted gateroad deformations were assessed through comparing them with the results of underground measurements.