Stability and Control of Retracement Channels in Thin Seam Working Faces with Soft Roof

Figure 3

Schematic diagram of the location of the main roof fracture and the retracement channel. (a) Above the gob. (b) Above the hydraulic support. (c) Above the retracement channel. (d) Above the solid coal.

(a)

(b)

(c)

(d)