The fire in the Jharia coalfields – located around 270 km from capital Ranchi – was first detected in 1916.
The fire started due to internal combustion of flammable gases present in the mines and has been burning continuously since then. Mining in Jharia started in 1896.
The coalfields are spread over 30 sq km in Jharia, around 12 km from Dhanbad.
A plan to stop the spread of fire by digging a trench across its path was could not be implemented due to reluctance of several families to shift from their homes.
The trench digging involved shifting of about 412 families living in the vicinity.
Out of around 80,000 families living in the area, 3,000 have been rehabilitated by the Jharia Rehabilitation and Development Authority (JRDA) in other places.
The district administration had started work to dig a 60 metre wide and 300 metre deep trench in 2011 but later suspended.
The residents had demanded their shifting to land of their choice to which the district administration and the JRDA didn't agree.
JRDA rehabilitation officer Gopalji said that the residents' reluctance to shift to safer places has caused delay in initiating steps to save public property.
The Bharat Coking Coal Limited (BCCL) has requested the JRDA to initiate fresh talks with the residents, Gopalji said. BCCL owns 81 underground and overground mines in Jharia.