Elimination of Coal and Gas Outburst Dynamic Disasters in Dengfeng Coalfield through Gas Extraction Based on Extremely Thin Protective Coal Seam Mining

Table 1

Gas outburst parameters of No. 2₁ coal seam.

Gas outburst parameters	Measured value	Detailed Rules of Coal and Gas Outburst Prevention and Control	Overweight (yes or no)	Conclusion
Gas pressure (MPa)	1.17	0.74	Yes	No. 21 coal seam has serious outburst danger
Gas content (m^3/t)	9.74	8
Damage type of coal	IV, V	III, IV, V
Initial speed of gas diffusion (mmHg)	12∼27	10
Solidity factor	0.1∼0.18	0.5
Dynamic phenomenon of mine gas disasters	No. 21 coal seam in the adjacent mines has experienced many coal and gas outburst accidents.