STABILITY ANALYSIS OF SILL PILLAR ON UNDERGROUND MINING SUBLEVEL STOPING WITH ANALYTICAL METHOD

• Main Author: Leonard, Calvin
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/44114
• Institution: Institut Teknologi Bandung

Horizontal pillar (sill pillar) is an important element in underground mining that uses stoping. The stability of the pillar is very influential on the overall stability of the mine and company profits, so it is necessary to extract the sill pillar as much as possible safely. This study aims to develop an analytical equation to calculate the thickness of the sill pillar to obtain the Factor of Safety of the sill pillar (FoSp) which can be considered as a preliminary study in mining activities. The equation is formed by analyzing on a narrow, tabular, and steeply dipping orebody, on the condition that the upper stope has been filled and the bottom stope has not been filled. Parametric studies have been conducted on analytical equations resulting from this study, with the result that the FoSp value increased significantly when the sill pillar thickness, width, and cohesion values increased. The parameters used in the equation are the orebody dip angle, horizontal and vertical stress ratio, then the width, depth, and height of the stope, as well as cohesion, internal friction angle, and specific gravity of the sill pillar and backfill material. The sill pillar safety factor generated from the analytical method from this study will be compared with empirical method and with 2D numerical method (Finite Element Method). Comparisons were made on sill pillar thicknesses of 2, 5, 10, 15 and 20 meters. The results of calculations on the analytical method approach the results of calculations on the empirical and numerical methods, and the optimal sill pillar thickness from the analytical method = 10-20 m.