Fig 1.
Schematic of sealed oxygen consumption experimental device.
Fig 2.
Experimental curve of closed oxygen consumption of Qipanjing coal sample.
Fig 3.
Schematic of the “three zone” distribution of the goaf in Qipanjing Mine.
Fig 4.
Observation and measurement results of wind speed along the 11101 working face.
Fig 5.
Observation and measurement results of air volume along the 11101 working face.
Fig 6.
Model drawing of gob-side entry retaining goaf retention in Qipanjing Mine.
Fig 7.
Flow field distribution of the oxygen volume fraction in the goaf at 0% air leakage.
Fig 8.
Flow field distribution of the oxygen volume fraction in the goaf at 1% air leakage.
Fig 9.
Flow field distribution of the oxygen volume fraction in the goaf at 5% air leakage.
Fig 10.
Flow field distribution of the oxygen volume fraction in the goaf at 10% air leakage.
Fig 11.
Change curve of the spontaneous combustion danger area under different positions of the working face.
Fig 12.
Change curve of the spontaneous combustion danger area under different air leakage.
Fig 13.
Grouting measures and oxygen distribution in the goaf after ideal grouting.
Fig 14.
Distribution results of the oxygen flow field in the goaf with different nitrogen injection rates.
Fig 15.
Nitrogen injection effect curve under different nitrogen injection amounts.