# Development and Application of Unesaled borehole Leakage Detection Device Based on Flow Method
## 4 Conclusions  
In this paper, a new unsealed extraction borehole leakage detection technique and a corresponding air leakage disposal method were proposed with the aim of improving gas extraction levels in mines, reducing gas emissions, and enhancing gas resource utilization. The following conclusions were drawn from this study.  
1. A new type of air leakage detection device for borehole gas extraction in coal mines has been developed to address the problem of a more cumbersome operation and longer testing period of the existing air leakage detection devices. By comparing the flow of gas extracted at different test points, it is possible to determine whether there is air leakage around the borehole, and the specific leakage position and leakage amount. This device has the advantages of simple operation and a short test period.
2. In view of the shortcomings of the \"three plugging and two injection\" secondary sealing technique, this paper proposes the \(\Phi\)10 mm sealing capsular bag secondary sealing method. Field tests showed that the air-gas mixture flow in the test borehole was reduced by a factor of approximately 1.55 and the concentration of pure seam gas was increased approximately six times after the disposal of the leaky position.
3. The combination of the leakage disposal method and the leakage detection device can accurately seal the unsealed borehole at the position of the leak, thus avoiding the blindness of secondary sealing, reducing the cost of sealing boreholes, and effectively ensuring the effectiveness of gas extraction from the borehole.  
Figure 8: Air–gas mixture flow from 5# and 6# boreholes.  
Figure 9: Seam gas concentration of 5# and 6# boreholes.  
**Author Contributions:** Conceptualization, Q.H. and H.C.; Methodology, Q.H., H.C. and X.C.; Software, Q.H. and K.A.; Formal analysis, Q.H. and Z.W.; Data curation, Y.Y. and G.X.; Validation, Y.Y. and G.X.; Supervision, H.C., Y.Y. and X.C.; Writing--original draft, Q.H. and H.C.; Writing--review and editing, Q.H., H.C. and Y.Y.; Project administration, Y.Y. and G.X.; Funding acquisition, H.C. All authors have read and agreed to the published version of the manuscript.  
This work is financially supported by the Scientific and Technological Breakthrough Project of Henan Province (242102321030), the Henan Provincial Natural Science Foundation (242300421651 and 242300421012), the Innovation and Entrepreneurship Training Program for College Students (202210460028), the Fundamental Research Funds for the Universities of Henan Province (NSFRF230401), the Safety Discipline \"double first-class\" Creation Project of Henan Polytechnic University (AQ20230713 and AQ20230305), the Innovative Research Team in University of Henan Province (24 IRTSHN013), the Research Fund of Shandong Coalfield Geological Bureau (2022-004), and the Innovation Training Program of Henan Polytechnic University (202310460098).  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** All data used to support the findings of this study are available from the corresponding author upon request.  
The authors declare no conflict of interest.