The crushing is to reduce large lumps to fragments, nearly to 1/2 inch size in many cases. The crushing action in all crushing machines (crushing) results from forces applied to the particles by some moving part working against a stationary or some other moving part. It is the first stage of size reduction. It has to crush run-of-mine ore contains large size particles. It requires greater force to apply on particles. Hence the crushers are very rugged and massive. Crushing is generally a dry operation. No crusher is capable of producing a very fine product from an extremely coarse feed and is usually performed in two or three stages depending upon the extent of size reduction needed.