# Development and Application of Unesaled borehole Leakage Detection Device Based on Flow Method
## 3 Results and Discussions
### Air Leakage Disposal Technique
#### 3.2.2 Leakage Disposal Effect  
After detecting the specific leakage locations of the 5# and 6# boreholes with the new air leakage detection device proposed in this study, the above-mentioned \(\Phi\)10 mm sealing capsular bag secondary sealing method is used for leakage disposal. After detecting the air-gas mixture flow before and after the secondary sealing, the changes in the seam gas concentration in the mixture were detected by the optical gas detector. The specific detection process of the optical gas detector is as follows.  
1. Preparation: Check the detector chemical reactants, gas sample channel, and air tightness of the suction ball to confirm its good performance. The chemical reactants include the calcium chloride, silica gel, and sodium lime to make sure that they are not invalid. Then, check whether the gas sample channel and suction ball are leaking.
2. Zeroing: Place the instrument in air, and pinch and release the suction ball several times to ensure that the zero scale of the micro-reading disk (decimal display disk) coincides with the pointer and that the selected black baseline coincides with the zero position of the dividing plate (integer display panel).
3. Measurement: Extend the rubber tube connected to the air inlet to the air-gas mixture extracted, press the suction ball for more than 10 times, and ensure that the gas to be measured enters the gas chamber. Press the light source electric gate and observe the position of the black baseline and pointer from the eyepiece. Read out the integer number shown on the dividing plate and the decimal number shown on the micro-reading disk; the sum of the two is the measured gas concentration.  
The seam gas concentration was tested for 8 days in 5# and 6# boreholes following the above testing process. The changes in the air-gas mixture flow and seam gas concentration in the mixture before and after the secondary sealing are shown in Figures 8 and 9.  
From the 5 th day, the \(\Phi\)10 mm sealing capsular bag method was carried out to seal the 5# and 6# leaky boreholes for the secondary sealing. It can be seen from Figure 8 that before the disposal of the leakage around the 5# and 6# boreholes, the air-gas mixture flow was as high as 0.51 m\({}^{3}\)/min. After the secondary sealing of 5# and 6# boreholes by the \(\Phi\)10 mm sealing capsular bag method, the air-gas mixture flow decreased to 0.33 m\({}^{3}\)/min and 0.29 m\({}^{3}\)/min, respectively, which was decreased by a factor of approximately 1.55 and similar to other boreholes. The seam gas concentration in the air-gas mixture in 5# and 6# boreholes was improved by six times after the secondary sealing, as shown in Figure 9, which shows the significant increase in gas extraction efficiency.  
Compared with the traditional method of \"three plugging and two injection\", the air leakage disposal method proposed in this paper avoids the blindness of the secondary sealing. It can also accurately seal boreholes at the position of leaks, which saves the cost of sealing boreholes in mines and effectively ensures the effectiveness of gas extraction from boreholes.  
Figure 7: Principle of \(\Phi\)10 mm sealing capsular bag secondary sealing. 1—Borehole; 2—\(\Phi\)10 mm extraction pipe with capsular bag; 3—\(\Phi\)50 mm extraction pipe; 4—Grouting tube; 5—Capsular bag 1; 6—Capsular bag 2; 7—Secondary sealing capsular bag.