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 4

The parameters of in situ stresses.

Project	/m	/MPa	/MPa
1	0	0	0
2	1000	52.35	41.69
3	1500	73.35	58.19

Note: is the mining depth. is the horizontal stress. is the vertical stress.