Division Method of Coal Spontaneous Combustion Zone in Multi-layer Goafs Based on Fracture Development Law

ABSTRACT

In order to accurately divide the coal spontaneous combustion area of multi-layer goafs in shallow coal seam group so as to take effective control measures, a mathematical model is established on the basis of the seepage equation of porous media and the balance equation of oxygen concentration to study the development law of fracture channel under the influence of repeated mining. The results show that the boundary of the goaf has a higher degree of deformation and damage than the inside of the goaf. With the advance of the working face, the position of the area with large porosity in the back becomes higher, while the area with large porosity above the mining space continues to expand forward and maintain a slender shape. According to the theoretical and experimental analyses, the goaf of 22409 working face in Nantun Coal Mine is divided into extremely easy air leakage area, easy air leakage area, weak air leakage area and hard air leakage area.

KEYWORDS:

• Fracture development
• mathematical model
• shallow coal seam group
• multi-layer goafs
• porosity

Acknowledgments

The authors gratefully acknowledge the financial support from the National Natural Science Foundation of China (51774181) and the “Science and Technology to power the Economy 2020” Key Projects (SQ2020YFF0426365).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [51774181]; “Science and Technology to power the Economy 2020” Key Projects [SQ2020YFF0426365].