Study on the Key Factors of Terminal Mining Line Layout in Repeated Mining of Close-Distance Thick Coal Seams

Figure 5

Evolution process of stress arch shape in upper coal seam mining. (a) 50 m, (b) 100 m, (c) 150 m, (d) 160 m, (e) 170 m, and (f) 210 m.

(a)

(b)

(c)

(d)

(e)

(f)