Pillar dimensions optimization in room-and-pillar mining in underground mines

Abstract

Research objective is to optimize pillar dimensions in room-and-pillar mining in underground mines. Methods of research include analyzing theory and practice in this field and carrying out engineering forecast for the prospects of room-and-pillar mining. Results. The article explains the urgency of pillar dimensions optimization aimed at ensuring personnel, equipment and subsoil safety. The article shows the role of mining-geological and technological factors that weaken the rock mass and introduces the resulting coefficient of pillar design diameter increase for a pillar within the stress-strained rock mass system. Formulas are presented calculating safe pillar increase parameters to compensate for its weakening caused by the manifestation of natural and man-induced factors of various origins. The order of weakening coefficients quantitative values is determined based on specific mining conditions and established regularities, including those depending on probabilistic indices. Weakening coefficients have been characterized considering the data about the factors behaviour. The dependence between the pillar strength and the pillar base strength has been extended. The role of stresses crucial for the pillars is revealed, and an algorithm for their forecast based on probable mathematical models is recommended. Conclusions. Based on this study data, pillar dimensions in room-and-pillar mining in underground mines can be optimized. It is recommended to use the research results when designing an ore extraction technology and adjusting the development parameters