Study of Strata Behavior in Multi-Seam Longwall Mining under Shallow Depth of Cover

摘要

The paper gives the salient physico-mechanical properties of the overlying rocks of two topmost seams RVII and RVIIA of Jhanjra Project where mechanized longwall retreat mining with caving deploying powered supports is being carried out. The experience of mining 17 panels in these two seams under shallow depth of cover, at places even as low as 35 m, has been collated with respect to strata behaviour in multi-seam longwall mining. Both regular and periodic weighting have been discussed. An attempt has been made in search of the reasons for such strata behaviour through interpretation of borehole data. Finally, the paper shows how systematically the past experiences had been incorporated in evolving suitable technology for shallow and hard roof management.