Evolution Law of Overburden Longitudinal Connected Fissures in a Shallowly Buried Coal Face with Thin Bedrock

Figure 6

Measurements of a longitudinal connected fissure in bedrock. (a) Fissure inoculation. (b) Fissure opening. (c) Fissure closing. (d) Fissure compaction.

(a)

(b)

(c)

(d)