History of Technology in India, Vol. I: From Antiquity to c. 1200 A.D. v1.c12.s1.t6.13

v1.c12.s1.t6.13

Fire-setting was the major means of extraction. The characteristic holes created by the fires suggest that the main impact was in the floor with a reduced effect the higher above the fire the flames climbed producing the characteristic arched roof form. Thus sinking a decline was the preferential mode of attack, whilst working up - dip was done by creating and driving forwards holes in the floor. A typical depth affected by a single burn seems to have been 5 cm. Many large pieces of rock, sometimes too heavy to lift, suggest mechanical breaking methods were used, probably using iron tools and perhaps a battering ram. ‘Gad’ and wedge marks were observed mainly in narrow slits.