Design and Application of Blasting Parameters for Presplitting Hard Roof with the Aid of Empty-Hole Effect

Figure 17

Evolution law of fracture field. (a) 196.2 μs. (b) 341.5 μs. (c) 490.1 μs. (d) 681.3 μs. (e) 953.7 μs.

(a)

(b)

(c)

(d)

(e)