Construction method of transparent working face based on borehole radar

The high-precision detection of coal rock interface is the key and difficult point to construct the three-dimensional geological model of intelligent mining. A method is proposed to construct regional coal rock interface geological model and realize transparent working face by using single hole reflection radar in the hole along coal seam and multi hole detection results. For single borehole radar data, the coal seam radar wave velocity is calculated by using the slope of roadway wave in-phase axis, and the spatial constrained migration imaging is used to realize the accurate calculating of coal seam top/floor reflection interface. Three transparent working face construction modes matching the actual mining are formed: the long boreholes mode before mining, the short boreholes mode during mining and the joint mode of two modes. The experimental application of the short boreholes mode in 31004 working face of a mine in Shanxi Province shows that the geological model of the working face based on borehole radar depicts more detailed local information than the geological model originally constructed by collecting other information. Compared with the actual measurement after mining, the maximum error of the coal seam top interface is 0.57 m; the maximum error of the coal seam bottom interface is 0.54 m; and the coal thickness error is 0.30 m. The results show that the borehole radar can detect the interface between coal seam and roof/floor with high precision, and the construction of transparent working face can be realized by combining multi boreholes.