Vallar plans to increase its shareholding in Indonesia’s Bumi Resources to 25% to gain an indirect controlling stake in Kaltim Prima Coal (KPC) mine operated by Bumi, in Kalimantan, Indonesia.

The Bakrie family that owns Bumi Resources has a majority stake in Kaltim Prima Coal and India’s Tata Group holds a 30% stake.

Bumi Resources and Vallar’s chief financial officer Andrew Beckham told the Financial Times that the firm expects Bakrie’s approval to increase Vallar’s stake in Bumi Resources through a share swap in the coming month.

The Environment Ministry of Indonesia placed the mine on its environmental watch list after its 2010 operations review showed wastewater treatment problems.