The Quarrying of Granite in India

Abstract

At Bangalore, in Southern India, the quarrying of granite slabs by means of wood fire has been brought to such perfection, that an account of the method may not be out of place. The rock is a grey gneissose granite of very irregular composition through unequal segregation of hornblende and the presence of numerous felspathic veins. But it is otherwise very compact, and forms solid masses uninterrupted by cracks for several hundreds of feet. Only near the surface the rock is found split parallel to the surface. In one quarry there is thus, for instance, a 4 feet thick horizontal layer of rather weathered rock, underneath this another layer of fresh rock 3 feet thick; but below this the rock is entirely fresh, and not split. These layers are probably due to the variations of temperature, daily and seasonal.