The mechanisms controlling pillar load transfer from an overlying seam to subadjacent workings is investigated. Mine geometry and geology are researched as major variables affecting interaction between contiguously placed seams. The thesis includes photoelastic experimentation, finite element modeling, and analysis of multi-seam room and pillar mine case studies from the Appalachian region.

A structured approach first establishes theoretically based trends, confirms their existence in the field, and finally results in invaluable multi-seam mine design guidelines. Stratification, lithology, and size of the interval between seams, and the extraction ratios of the seams are parameters found responsible for defining the stability of a lower seam overlain by either past or present mine operations.