What is the minimum resistance line? What is the effect?

In engineering blasting, the shortest distance from the center of the drug pack or the center of gravity to the nearest free surface is usually called the minimum resistance line. As shown in Figure 1.

Figure 1 Minimum resistance line under various blasting conditions

(É‘) flat spherical blasting; (b) flat vertical blasting; (c) vertical blasting;

(d) parallel blasting of steps; (e) blasting of hillside drug room

Whether the minimum resistance line is reasonable or not is directly related to various blasting indicators. In fact, the minimum resistance line is the direction with the least resistance to rock during blasting. In this direction, the rock has the highest speed and the blasting effect is the most concentrated. Therefore, the minimum resistance line is the dominant direction of the blasting action and the dominant direction of the throwing action.