Optimal Support Spacing for Steel Sets: Omerler Underground Coal Mine in Western Turkey

Abstract

This paper presents a method to determine the optimal set spacing for rigid-type galvanized I profile (GI) and Toussaint-Heintzmann (TH)–type yielding steel sets in Section A of the Omerler underground coal mine. The rock mass rating (RMR) and geological strength index (GSI) were determined by using field data and the measured mechanical properties of intact rock samples. The support pressure was calculated using the convergence–confinement method, and the support-capacity curves were plotted for a range of set spacing values. The intersection of the support-pressure and support-capacity curves was identified as the minimum set spacing that can provide stability in the roadways. A study to determine the optimal and most cost-effective designs was conducted for hanging wall, footwall, and coal sections, and these designs were verified using FEM software. According to the FEM results, applying the GI 12 profile to the set spacing decreases the deformations around the roadways for all hanging wall, footwall, and coal sections. In contrast, TH 34–type yielding steel sets will only work for coal sections because of the low deformation rates of hanging wall and footwall.