Underground mining of thick coal seams

This paper reviews underground mining methods for total thickness of a thick coal seam in single lift (TTTCSSL). Review shows the required engineering for extraction of thick seams needs to be fitted with thickness of the seam, behavior of rock-mass and surrounding stress conditions for efficient mining. Variants of TTTCSSL are able to extract a maximum 10–12 m thickness only. An improvement in bending moment of the overlying coal band in longwall top coal caving (LTCC) provides better under-winning opportunity for the roof coal band. An acceptable limit of 25 MPa compressive strength of coal for the success of LTCC may be increased under favorable geo-technical conditions. Bord and pillar in India adopted induced caving of roof coal band for single lift depillaring of total thickness (SLDTT) of a competent thick coal seam developed along floor. Case studies are given to arrest the adverse effects of extraction height on pillars.