| Description |
Drill and blast is a common mining technique. It is used to damage the rock for extraction and leave the remaining rock for support. Its perfection is the goal of cautious blasting. The theory of cautious blasting describes the relationships connecting the blasthole, the explosive, and the rock mass to the resulting damage. Blast damage is caused by the propagation of stress waves and the expansion of gas. The focus is on the damage caused by the stress waves, in particular, the radial compressive stress wave. Stress waves decay by three mechanisms: geometric spreading, damage, and seismic attenuation. Where the stress has decayed to its dynamic compressive strength the damage ends. Therefore, if one knows the initial stress, the amount of stress decay, and the strength, then the damage distance can be computed. |
