Control Effect Of Igneous Intrusion On Methane Reserve And Outburst Disaster Prevention Technology Based On Huaibei Coalfield

Huaibei Coalfield was influenced by the Cretaceous Yanshanian magmaticmetamorphism, where coal and gas outburst disasters seriously. This paper takes coal samplesfrom the Wolonghu Mine and Haizi Mine at various distances from sills as the main studyobject, systematically carrying out study of various aspects on the spatial-temporal evolutionof regional magmatism process, influences of igneous intrusions on coal rank, microporecharacteristics and adsorption capacity, the control effect of the thermal evolution and trapeffects of the sill intrusions on the gas occurrence and outburst, the partition controltechnology and engineering practice. The main conclusions are as follows:Approaching the sill in the Wolonghu Mine, vitrinite reflectance (Ro) levels increasedfrom2.74%to5.03%, and the thermal aureole of the sill~60m. Three zones of the No.10coal seam along this gradient were identified as corresponding to: contact metamorphic zone(0-5m from sill), thermal evolution zone (5-60m from sill), and unaltered zone. Approachingthe~120m extremely thick sill,Ro increased from2.30%to2.78%, and the thermal aureoleof the sill~160m. Two zones along this gradient were identified as corresponding to: thermalevolution zone (60-160m from sill) and unaltered zone (160m away from sill).The gas occurrence of coalseams near magmatic intrusion in the Wolonghu and HaiziMines was obtained. It is concluded that the contact-metamorphism decreased the adsorptioncapacity of Wolonghu coal in the contact metamorphic zone, and the thermal evolution of sillincreased it of the thermal evolution zone. The thermal evolution of the extremely thick sill inHazi Mine increased the adsorption capacity of the thermal evolution zone (60-160m fromsill). Two and eleven outbursts have occuured in sill thermal evolution zone of the Wolonghuand Haizi Mine. There was abnormally high formation pressure in the No.10coal seam of thering-sill trap zone in the Wolonghu Mine. The CH4content and composition of sill coveredcoal were higher than those without sill coverage coal in the Haizi Mine.Study on a method and procedures to determine the sensitive indicators and critical valueof coal seam with outburst dangerous in igneous intrusion mine. According to the relationshipbetween gas contents and pressures of the No.10coal seam in the Wolonghu Mine.Considered the factor that of the No.10coal seam was high rank anthracite and with highresidual gas content, showed the gas content as the region sensitive indicator is more safer andreasonable, with the critical value of9.50m3/t. Field test the cuttings indicators of the No.10coal seam found thatK1is more sensitive than h2, and the drilling cuttings amount S is notsensitive.The gas deposit law of the No.10coal seam in Wolonghu Mine wae obtained. In outburst danger zone of the No.10coal seam, where surrounding rock lane borehole wearseam drilling, along the coal seam drilling and infill drilling in the thermal evolution zone gasextraction mode was implemented. After the region methane pre-pumping, the measuredmaximum gas content of the coal face108was7.82m3/t, less than the critical value of theregional sensitive indicator9.50m3/t. The outburst dangerous of coal face108has beeneliminated. Engineering practice verified the effectiveness of the partition control methanetechnology and sensitive indicator threshold.