Research and application of cut blasting with slotted charge.

Slotted charge has significant guiding effect on blast energy. Slotted charge was introduced into cut blast, and the idea of "cut to drivage" was put forward. Divided a certain range of central rock part from the surrounding with slotted charge blast. This method avoids the disadvantage of single free surface and great clamping effect. Utilized the blast energy of following boreholes, break the rock and throw the fragment out of cavity. Perform numerical simulation of rectangular cut blast. The energy along kerfs' direction is released in priority, and the peak value of point along kerfs is above 200 MPa, which forms the penetration of cracks. In separate cut blast, the utilization rate of borehole reaches to 97.8%. In full section blast,the average utilization rate of borehole reaches to 96.9%. Field tests validate the feasibility of cut blasting with slotted charge. [ABSTRACT FROM AUTHOR]