Study on Gas Migration Law of Mining Coal Seam under the Influence of Normal Fault

Figure 4

Development and distribution map of overlying fissures in No. 5 coal seam.

(a) Excavation 20 m

(b) Excavation 40 m

(c) Excavation 60 m

(d) Excavation 80 m

(e) Excavation 100 m

(f) Excavation 120 m

(g) Excavation 140 m

(h) Excavation 160 m

(i) Excavation 180 m

(j) Excavation 200 m