Blasting for Fracturing and Improving the Permeability of Deep, Soft, Outburst Prone Coal Seams Using Blasthole and Relief Hole Drilled into the Underlying Stratum: Optimal Hole Distance

Table 1

The physiomechanical parameters of the coal, rock, and blasthole stemming.

Name	/(g·m^-3)	/GPa		/Mpa	/Mpa
Coal	1.380	5.3	0.32	0.45	7.2
Rock	2.583	33.4	0.235	3.19	69.592
Hole sealing	1.620	1.31	0.09	3.11	0.98

Note: is the material density. is the elasticity modulus. is the Poisson ratio. is the compressive strength. is the tensile strength.