Prediction and Control of Coal Spontaneous Combustion in a Multi-fault Fully Mechanized Top Coal Caving Face at the Mine Field Boundary

ABSTRACT

To mitigate coal spontaneous combustion in the fully mechanized caving face at the boundary of Jining No. 2 coal mine, the accurate prediction of the location and degree of coal spontaneous combustion was realized through theoretical analysis, experimental prediction, and field observations. The concentration changes of CO, C₂H₆, and C₂H₄ during coal oxidation and heating were analyzed. By combining a mathematical prediction model with CO generation rates for different temperature thresholds, the CO concentration in the return air corner was predicted to assess the coal spontaneous combustion degree in the goaf. Through the analysis of the coal spontaneous combustion oxygen concentration limit and three zones, the spontaneous combustion position in the goaf was obtained and verified by drilling. Moreover, based on the mine’s existing glue injection system, we proposed a new system with long-distance and large-flow transportation, flowrate control, and precise slurry concentration control. The results showed that the remaining coal temperature in the goaf reached the critical temperature (60–80 C). The highest temperature point in the goaf was located 12 m behind support #10. The proposed glue injection system increased the efficiency of coal spontaneous combustion prevention and control.

KEYWORDS:

• Coal spontaneous combustion
• fully mechanized top coal caving face
• prediction
• fire-extinguishing technology
• mine field boundary

Acknowledgments

The authors gratefully acknowledge financial support from Xianyang City Science and Technology Research Project (Grant No. 2018K02-17), Science and Technology Public Relations Project of Shaanxi Energy Vocational and Technical College (Grant No. 18KYG01), the National Key Research and Development Program Key Special Projects (Grant No. 2016YFC0801800).

Declaration of interest statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Additional information

Funding

This work was supported by the Xianyang City Science and Technology Research Project [2018K02-17]; National Key Research and Development Program Key Special Projects [2016YFC0801800]; Science and Technology Public Relations Project of Shaanxi Energy Vocational and Technical College [18KYG01].