Open-pit Blasting Technology Research on Super Deep Hole and Large Resistance Line

There was a special working face with an ultra-high bench and a large resistance at the 410 platform of a mine in Qingyuan city, which required one-time blasting. This working face had a bench height of 30m, a length of 80 m, and a face angle of 45°~80°. Due to the large bench height, small face angle, and the different face angles of the upper and lower parts, it was difficult to conduct the blasting construction. Before blasting design, the RTK measuring instrument and total station were used to measure the topography of the detailed working face, and then calculate the slope angle of each position of the face according to the topographic map. According to the rock properties, the construction experience and the drilling rig type, the powder factor and blast hole diameter were determined. Based on the above results, the toe burden, drilling angle, depth and spacing of the first row of blast holes were then deigned. Similarly, the burden, drilling angle, depth, spacing of the following rows of holes were also determined. After the hole parameters were determined, the charging structure was designed according to the burden of each row of holes, the rock volume of each hole, powder factor, and the principle of uniform blasting action. Finally, the initiation network was designed by the software of 3Dmine based on the direction of rock movement and the earthquake-proof requirements of the protected objects. During the construction process, the key links such as hole layout, hole depth measurement, drilling, charging, and network connection were strictly controlled, and positive results were obtained after blasting.