Internal structure of coal seams and mechanical stability

CIM Bulletin, Vol. 75, No. 841, 1982

M.L JEREMIC, Professor of Rock Mechanics and Mining Engineering, Laurentian University, Sudbury, Ontario

The syngenetic and epigenetic mechanics of sedimentation and deformation of coal seams resulted in various types of internal structure, as listed below:TYPE I—massive structure with evenly distributed coal constituencies of integrated mechanical properties. TYPE II—broad-banded structure, with bright and dull coal bands of differential mechanical properties. TYPE III—heterogeneous structure, with sheared coal bands and partings of sectional mechanical properties. TYPE IV—contortional structure, with refolded coal layers and deteriorated mechanical properties. TYPE V—porous structure of orogenically crushed and pulverized coal, with disintegrated mechanical properties.The study suggests criteria for the estimation of coal seam internal structure (gamma-gamma density log and cracks density log), which might be related to the evaluation of strata stability and coal mineability.

Keywords: Coal structure, Coal seams, Mechanical stability, Rock mechanics, Sedimentation, Deformation, Density logs, Fractures, Pillar deformation, Strata control.