The Static Breaking Technique for Sustainable and Eco-Environmental Coal Mining

Figure 8

The expansion status of the latter occurring cracks C and D over time.

(a) 𝑡=40 min

(b) 𝑡=50 min

(c) 𝑡=60 min

(d) 𝑡=80 min

(e) 𝑡=150 min

(f) 𝑡=240 min