Research on Formation Mechanism and Evolution Pattern of Bed Separation Zone during Repeated Mining in Multiple Coal Seams

Figure 13

Borehole peeping results ((a)–(c) borehole depth is 10 m; (d)–(f) borehole depth is 20 m; (g)–(i) borehole depth is 30 m).

(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)

(i)