Case Studies of Comprehensive Gas Control Method during Fully Mechanized Caving of Low-Permeability Ultrathick Coal Seams

Figure 12

Gas drainage in roof caving and fissure zones of the No. (9-15)06 panel. (a) Overburden structure of (9-15)06 panel and roof high-level gas drainage boreholes. (b) Boreholes in high drilling site. (c) Metering installation of gas drainage.

(a)

(b)

(c)