Determination of rock bolt and steel set behaviors used in control of longwall tailgate roof strata by numerical analysis

Rock bolting has become the primary support system in the underground coal mining industry in many regions around the world. This study consists of the design of rock bolt support system for the tailgates of Turkey Coal Enterprises - Garp Lignite Enterprise-Ömerler underground coal mines-A6 longwall panel. In the first phase of this study, which consists of three stages, in-situ and laboratory studies were carried out to determine the rock mass and material properties of coal and wall rocks. In the second stage, with the help of the obtained database, empirical support design approaches and Phase2 (v6.0) program which two dimensional numerical modeling studies were carried out for the determine of preliminary design of the rock bolt support system. In the last stage, final modeling studies were performed with FLAC 3D (v6.0) program by using preliminary design results. The model studies were created for two different situations: excavation of longwall tailgates and coal face advancement. In both cases, models were created for the steel set support and 3 different types of rock bolt support, and the model results were analyzed. As a result of these analyzes, it was determined that the steel set support system used in Ömerler underground coal mine was exposed to more deformations and stresses caused by roof stratas than the rock bolt support system. In the numerical analysis for trapezoidal roadway, it was found that Swellex, Resin and Cable rock bolts were quite successful in terms of stability in pillars and tailgates. As a result of the studies, a rock bolt support design was proposed for Ömerler underground coal mine site.