Rock-Mechanics Instrumentation Program for Kaiser Steel Corporation's Demonstration of Shield-Type Longwall Supports at York Canyon Mine, Raton, New Mexico. Volume 1. Final Report

摘要

This report presents the results of a rock mechanics instrumentation program designed to determine the rock mass response due to longwall mining a thick coal seam utilizing shield-type supports at the York Canyon Mine near Raton, New Mexico. The data collected during this study is unique in that it represents the results from mining three adjacent longwall panels varying from sub-critical to super-critical in a known geologic environment with cross- and along-panel topographic variations. Data from the program indicated the following: (1) Topography significantly influenced the magnitude and distribution of surface movements. (2) The study failed to substantiate the theory that the angle of draw decreased as the depth of overburden increased. (3) Subsidence started when the face was an average of 0.33h (h = overburden depth) from a given surface point and was essentially completed when the face was 0.9h beyond the surface point. (4) Underground mining activity produced almost instantaneous surface movement and major surface subsidence ceased almost as soon as mining ceased. (5) Topography influenced shield loading patterns only where the overburden depth was thin. (6) The width of the pressure abutment was apparently related to the depth of overburden. (7) The type of roof rock controlled the amount of roof-sag. (8) With longwall face advance, the roof tended to move away from surface topographic highs and towards the caved area. (9) Roof-floor convergence at the mining face was approximately one percent of extracted seam height. (10) The magnitude of roof-floor convergence out ahead of the mining face could be related to the face distance with a logarithmic curve function. (ERA citation 07:006701)