The ban has been implemented due to the sites having reached the Indian environment ministry’s output standards.

Coal India applied for an extension a year ago but has been forced to halt exploration because it is still waiting for approval from the ministry.

A ministry official told The Indian Times that the mining restrictions, barring even excavation of coal exposed during removal of surface soil, were expected to be lifted before the last quarter, which is considered crucial for meeting Coal India's production targets.

Lack of environmental clearances for expansion led to substantial revenue loss to the company in 2012-13 and could considerably narrow the gap between its coal production target and actual output for the current financial year.

It is predicted Coal India will miss its production target of 482 million tonnes by about 15-20Mt due to lack of environmental clearances.

It is reported that more than 4Mt of coal was exposed during removal of surface soil of Coal India’s Lakhanpur mine in Jharsuguda.

However, it cannot be excavated and transported to consumers and the electricity generating companies of West Bengal and Maharashtra due to pending permits for expansion of the project.