Theoretical and Experimental Study on the Mechanism of Instability and Firing Gas in Hard Quartz Sandstone

Table 2

Statistics of point spark, spark beam, and reaction time node of gas explosion at different gas concentrations.

Gas concentration	VOL% = 4.3%	VOL% = 6%	VOL% = 8.6%	VOL% = 10.3%	VOL% = 12%
Formative time of fire spark (s)	2.338	0.2171	4.676	2.4883	2.4883
Formative time of fire bouquet (s)	4.3253	1.6533	5.9786	5.4943	6.2959
Gas explosion time (s)	No gas explosion	No gas explosion	7.014	6.2458	7.9826