Capsule-Bag-Type Sealing Technology for Gas Drainage Boreholes and Its Application

Figure 1

Reasons for air leakage in drilling. 1: air leakage from drilling cuttings; 2: air leakage from fissures; 3: air leakage from the upper part of the filler; 5: pressure relief ring around the hole; 6: rock movement creates new cracks.