Ground Control in Multi-Level Room and Pillar Mines

摘要

This research is concerned with ground control in multiseam mining and relates mainly to the analysis of stress about multiseam room-and-pillar mines. The two variables of most concern are distance between seams and alignment of the pillars between seams. The first-year results of the 2-year investigation apply to the development phase of mining when the extraction is typically less than 50%. The second-year effort is concentrated on retreat mining and barrier-pillar safety when the extraction is typically greater than 50%. The procedures in both cases are readily applicable to more than two seams. Although two-seam mines are the most frequent type of multiseam operations, because of the potential for three-seam operations in the Western United States, a number of three-seam development analyses are also presented.