Ultra Deep Hole Blasting Cracking to Improve Excavating Efficiency of Hard Rock Roadway

To solve the problems of low excavation efficiency, large cutting tooth loss and serious dust in the tunneling process of full-section hard rock roadway in coal mine, the ultra-deep hole blasting cracking technology is proposed to increase the crack and damage range in the rock mass, and to keep the speed advantage of tunneling soft rock roadway. Taking Xinyuan Coal Mine as an example, the ultra-deep hole blasting design parameters are determined by improving the ultra-deep hole blasting technology and the typical rock sample static and dynamic experiments. The field test shows that the technical scheme can reduce the pick consumption by 59.8%, and the average dust amount decreases by 49.9% in the case of full-section hard rock, which significantly reduces the cost of tunneling and improves the working environment.