Analisis Kestabilan, Perancangan, dan Biaya Sistem Penyanggaan Stope Produksi Berdasarkan RMR Menggunakan Metode Elemen Hingga

Abstract

Underground mining faces significant technical challenges related to the stability of production stopes, which can pose risks to workplace safety, cause equipment damage, and lead to operational disruptions. This study aims to analyze the actual conditions of production stope using the Finite Element Method (FEM), determine the influence of variations in support systems based on Rock Mass Rating (RMR) on stope stability, and analyze the cost requirements of the recommended support system. The method used is a FEM-based numerical approach, utilizing secondary data such as rock characteristics, stoping geometry, elevation, and support specifications. Modeling was conducted under four conditions: no support, split-set bolt support, a combination of split-set bolts and wire mesh, and a combination of H-beams and forepolling wood. The research results indicate that the production stope at an elevation of 446 meters above sea level, with a geometry of 5 meters in width and 4 meters in height, is in an unstable condition, as evidenced by a strength factor (FK) ranging from 0.28 to 1.42—which falls below the minimum requirement of FK ≥ 1.5 as stipulated in Ministry of Energy and Mineral Resources Regulation No. 1827 K/30/MEM/2018. The maximum principal stress (σ₁) of 4.40–10.17 MPa exceeded 50% of the rock’s ultimate compressive strength (UCS) of 17.73 MPa, and the maximum shear stress of 2.30 MPa exceeded the rock’s maximum shear strength of 1.495 MPa. The split-set bolt support and its combination with wire mesh did not provide a significant increase in stability. The H-beam and forepolling wood support system proved effective in increasing the strength factor to 0.22–5.21 and met safety standards. The total cost required for a single 2-meter advance in the production stope was US$3,904.1.