Mining major BHP Billiton is set to begin coal production at its Haju mine located in Borneo island of Indonesia.
Initially, the mine is expected to produce an estimated one million tonnes of coal per year and around five million tonnes if fully developed.
The company confirmed that initial production will begin within a year, as part of a bigger project called IndoMet.
BHP's latest announcement has concerned local communities, with campaigners urging the company to abandon the project.
Friends of the Earth International campaigner Cam Walker told The Sydney Morning Herald: "That is devastating news for the climate and for the local people who have been rejecting this project for years."
Environmental groups believe that the expansion of IndoMet project in the central Kalimantan province, which BHP has a 75% stake in and is expected to cause damage to the rivers of the upper Barito basin.
Indonesian partner Adaro Energy owns the remaining 25% interest in the project.
In an opinion article published by ABC in 2013, Central Kalimantan resident Arie Rompas claimed that the company's proposal to proceed with open-cut mines would have an adverse impact on the area's fragile ecosystem.
BHP said in a statement that none of its mining leases crossed over 'protection forests'.
In November 2013, conservationists urged the company to drop its plans with regard to mining in central Borneo, claiming that it would damage the region that is inhabited by the endangered orangutan.
Although BHP insists that no orangutans have been found on its lease areas, it has reportedly relocated 280 that were found nearby to other parts of Kalimantan.