In 1917, L.S.S.O’Malley described the coalfields in the upper reaches of the Damodar as follows: “Near the western boundary of Jharia field is that of Bokaro, covering 220 square miles (570 km2), with an estimated content of 1,500 million tons; close by… is the Ramgarh field (40 square miles), in which, however, coal is believed to be of inferior quality. A still larger field in the same district is that called Karanpura, which extends over 544 square miles (1,410 km2) and has an estimated capacity of 9,000 million tons.”
The Bokaro coalfield lies between 230 45’ and 230 50’ North latitude and 850 30’ and 860 03’ East longitude. It spreads 65 km from east to west and 10 to 16 km from north to south. Bokaro West and Bokaro East are two subdivisions of the field separated almost in the middle by Lugu Hill (height 960.9 m).