Study on goaf spontaneous combustion prevention and control technology ofL type fully-mechanized top coal caving mining face in shallow depth seam

In order to prevent and control the spontaneous combustion of the coal left in the goaf of the fully-mechanized top coal caving mining face in a shallow depth seam, a systematic study was conducted on the seam occurrence and mining technology condition, coal quality characteristics, coal spontaneous combustion characteristics and spontaneous combustion symbol gas and index optimization of the L type fully-mechanized top coal caving mining face in Lutian Mine. In order to control the coal spontaneous combustion in the goaf, an air curtain set in the top corner of the coal mining face, sandbags wall, rational distributed ventilation volume and other preliminary prevention measures were implemented early or late in the coal mining face, the ventilation method of the coal mining face was changed from the exhaust type negative pressure to the forced positive pressure and the backfill and rolling, the plastic film sealing and other special prevention and control measures were conducted in the surface ground subsidence area. The results showed that after the backfill and rolling, the plastic film sealing and other special prevention and control measures conducted on the surface ground subsidence area, the carbon monoxide concentration in the goaf of the mine was reduced from 39×10-6 below to 7.5×10-6, the oxygen concentration in the goaf of the mine was reduced from 17.8% to 5% and thus a safety production of the L type fully-mechanized top coal caving mining face in a spontaneous combustion thick seam with a shallow depth could be realized.