Study on the Evolution Characteristics of Two-Zone Failure Mode of the Overburden Strata under Shallow Buried Thick Seam Mining

Figure 9

“Two-zone” failure mode evolution process of different key strata structure and mining height. (a) Multiple key strata structure (mining height is 5.3 m). (b) Multiple key strata structure (mining height is 3.0 m). (c) Composite single key strata structure (mining height is 5.3 m). (d) Composite single key strata structure (mining height is 3.0 m).

(a)

(b)

(c)

(d)