Determination of Water-Proof Coal (Rock) Pillar Height in Mining Coal Seam Group under Water-Bearing Rock Stratum

Figure 1

Expansion height of water-conducting fracture zone in grouping mining. (a) Expansion height of water-conducting fracture zone in the upper group coal mining. (b) Expansion height of water-conducting fracture zone in the lower group coal mining.

(a)

(b)