History of Technology in India, Vol. I: From Antiquity to c. 1200 A.D. v1.c12.s1.t2.10

v1.c12.s1.t2.10

The smelting was done with charcoal. Ancient furnaces in the vicinity of slag heaps show that these were always made of clay with clay tuyeres. The slag heaps cover a long area between Rakha mines and Roam and have variable depths up to 1.8 m. A typical analysis of slag near Mosaboni contains only 0.26% copper which is as good as can be obtained from modern smelters.