Deep hole pre-splitting blasting technology when fully mechanized coal mining face passes through high drop fault

In order to solve the problem, that the hard rock fault with a large throw hinders the advance of a fully mechanized mining face, this paper analyzes the disadvantages of the traditional method for passing through the fault and the existing technologie.Also, the paper carries out a systematic study on the deep hole pre-splitting blasting technology for passing through the fault with a large throw.Aiming at the problems of unclear occurrence of fault with a large throw and inaccurate designed path for passing through fault, it puts forward fault occurrence detection technology and the optimized layout for fault detection roadway.Based on the revealed information, the fault strike calculation model is established.Aiming at the problem that deep hole blasting technology is not suitable for working face and groove, it studies the key technology of pre-excavation blasting roadway, and puts forward the layout principle and calculation method of layout parameters of blasting roadway.It determines the scheme of deep hole pre-splitting blasting in blasting roadway, designs the construction method of ear chamber, and solves the problem of concentrated blasting with large amount of explosive.Based on the theory of rock blasting, combined with the characteristics of fault engineering with large throw difference, the blasting parameter selection and calculation method are completed by designing the hole diameter, hole depth, charge mass, plugging length, hole layout and blasting vibration safety control.The underground roadway of 2302N working face at Xinjulong Coal Mine reveals a hard rock fault with a comprehensive drop 12.5 m.Through the exposure points of lower roadway and six detection holes arranged in sequence, the initial strike of the fault extending to the working face is verified, and the vertical strike of the fault, the driving scheme along the floor of the coal seam and the driving scheme along the floor of the coal seam under the fault are designed.Based on the measured information, it plans the path through the fault.According to the change of fault occurrence in the path, it divides eight blasting regions, designs the blasting layout parameters in each region, and predicts and analyzes the blasting effect by means of numerical simulation.The application results show that the blasting fissure penetration effect is good, the consumption of shearer picks through the fault is reduced by 40%-50%, and the time is reduced to half compared with the time using traditional method through the fault.The technology for passing large throw fault have been successfully applied in many working faces in Xinjulong coal mine.It has achieved good results in ensuring high efficiency continuous mining, reducing the cost of passing through fault and ensuring blasting safety.The practice has proved that this technique is widely applicable in dealing with large throw fault at a fully mechanized mining face. © 2019, Editorial Office of Journal of China Coal Society. All right reserved.