Study on Law of Overlying Strata Breakage and Migration in Downward Mining of Extremely Close Coal Seams by Physical Similarity Simulation

Figure 4

Processing equipment: (a) ZS-100 fully automatic drilling machine; (b) SCM200 double-end grinder; (c) HJD-150A concrete sawing machine; (d) SC200 automatic core-taking machine.

(a)

(b)

(c)

(d)