Influence of Coal Caving Time and Tail Beam Swing Angle on the Evolution of the Coal Gangue Boundary Line during Top Coal Caving

Figure 5

The coal gangue boundary curve at different times. (a) The boundary curve at 20°. (b) The boundary curve at 22°. (c) The boundary curve at 24°. (d) The boundary curve at 26°. (e) The boundary curve at 28°. (f) The boundary curve at 30°. (g) The boundary curve at 32°. (h) The boundary curve at 34°. (i) The boundary curve at 36°. (j) The boundary curve at 38°. (k) The boundary curve at 40°.

(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)

(i)

(j)

(k)