Study on Layered-Backfill-Based Water Protection Technology of Thick Coal Seam in the Ecologically Fragile Mining Area in Western China

Figure 7

Evolution characteristics of water-conducting fractures in the overburden under different mining conditions.

(a) Caving mining

(b) 60% backfilled ratio

(c) 70% backfilled ratio

(d) 80% backfilled ratio

(e) 90% backfilled ratio