Abstract:
The Missouri S&T Experimental Mine supports teaching and research initiatives in mining and geological engineering; is used by the U.S. Army and by the Department of Homeland Security for tests and research and; hosts more than 6,000 visitors each year for educational and public awareness purposes. The Experimental mine employs the room and pillar underground mining method to extract dolomitic limestone of Jefferson City formation. In room and pillar mines, pillars play a significant role to providing support of the overlying strata. Pillar stability analysis has previously never been conducted at this mine to date. Pillar stability analysis is critical for safety of miners and safe working conditions. This fundamental research seeks to employ the Fast Lagrangian Analysis of Continua in three dimensions (FLAC3D) to determine modulus of deformability affect pillar strength. The numerical model was calibrated with Obert and Duvall empirical pillar strength equation. A multi-variant regression has been used to established relationship between the modulus of deformation of the rock mass and the pillar strength for various pillar shapes and sizes. It can be concluded that the pillar cases at Missouri S&T Experimental Mine are stable irrespective of the modulus of deformability. This is partly because the overburden loads imposed on the pillars are low.
Introduction
The Missouri S&T Experimental Mine supports teaching and research initiatives in mining and geological engineering; is used by the U.S. Army and by the Department of Homeland Security for tests and research and; hosts more than 6,000 visitors each year for educational and public awareness purposes. The Experimental mine employs the room and pillar underground mining method to extract dolomitic limestone of Jefferson City formation.
The use of room and pillar mining method requires that pillars are left in place to provide support for the overburden strata. The stability of the pillars are imperative for safety and economic reasons, hence pillar sizes must be designed to satisfy safety and economic constraints. Pillar design process involves estimating the pillar stress and the pillar strength and sizing the pillar until an acceptable margin of safety (ratio of pillar strength to pillar stress) is attained.
