Drilling Resistance

(drillability), the rate at which rock on the bottom of a drill hole (or blast hole) is broken down. Drilling resistance depends on the characteristics of the rock, the method used to break it down, the quality of the technical facilities, and the efficiency of the drilling technology. It may vary in the same kind of rock, increasing as the technical facilities, drilling technology, and drilling methods are improved. There are several well-known drilling-resistance classifications for rocks (for example, the Soiuzvzryvprom scale and the Standard Scale).