cimfr.csircentral.netcimfr.csircentral.net/31/1/S28.pdf · involved, making the coal extraction...
5
cimfr.csircentral.netcimfr.csircentral.net/31/1/S28.pdf · involved, making the coal extraction squarely non-feasible and also because of shallow depth of cover (adverse HIL ratio)
