Safety Uncovering Coal Seam Technology for Deep Shaft with Strong Outburst Risk

We study the stress distribution and coal outburst zone of shaft working face by theoretical analysis and field validation method. Result shows that there is a funnel-shape mining relief area underneath shaft working face and stress concentration area around the shaft. Additionally, we manage technological process of shaft uncovering coal in five stages. According to the actual conditions of shaft uncovering coal safety reconstruction in Qinan Coal Mine of Huaibei Mining Area, we use main technical measure (pre-draining borehole), intensive measure（cleaning borehole）and safety safeguard measure (metal skeleton, coal solidification), all these measures successfully completed the project of uncovering coal seam with strong outburst risk in 1 000 m-plus deep shaft.