The machining of rock materials.

Abstract

The penetration of a tool into solid rock is fundamental to all mechanical rock cutting processes. Rock in place in the Earth's Crust, can be considered as a semi-infinite solid since initially it presents only one free face for attack. Only by developing a second free face in the rock, however small, can excavation proceed. Man seems to have been aware of this, perhaps only subconsciously, since he first started trying to excavate a shelter for himself out of solid rock. The problems associated with rock excavation today are basically the same as those confronting the early cave-dwellers. We are still attempting to improve the design of tools, using materials that are readily available, economical to use, and resist breakage and wear. We continue to seek more efficient methods of attacking the rock thereby excavating a greater volume of rock for a given expenditure of effort resulting in increased rates of advance. Compared to developments in other scientific fields, however, rock excavation technology has seen few revolutionary innovations in its long history. The situation is such that rock excavation remains an art rather than a science.