LONDON-- Asia Resource Minerals PLC on Tuesday completed its $501 million separation from the Bakrie Group, bringing an apparent end to a long-running corporate governance saga at the controversial Indonesian coal miner.

The deal, originally agreed to in December, will see Asia Resource Minerals--formerly known as Bumi PLC--sell its 29.2% stake in PT Bumi Resources TBk to the Bakrie Group, the investment vehicle for one of Indonesia's most prominent families. The deal has been postponed several times since January to allow the Bakries time to raise the necessary funds.

As part of the deal, Asia Resource Minerals chairman Samin Tan has doubled his 23.8% stake in the company by acquiring the Bakrie Group's stake in the London-listed venture.

Asia Resource Minerals was formed in 2011 under the Bumi name, after the Bakrie family folded its coal assets into a shell company created by European financier Nathaniel Rothschild.

The venture subsequently suffered from boardroom rifts between Mr. Rothschild and the Bakries, falling coal prices and an investigation into alleged financial irregularities at its Indonesian coal assets. The company's share price has fallen 80% since its 2011 peak.

The public rows at Asia Resource Minerals have led to criticism that London has become too open to listings of emerging market resource companies. Last year Kazakh mining company Eurasian Natural Resources Corp. was delisted and taken private by its owners, whilst minority shareholders in India's Essar Energy have this year objected to its owners' offer to take the company private.

Asia Resource Minerals' CEO Nick von Schirnding said the company would now focus on turning around its remaining asset, an 85% stake in Indonesia's fifth largest thermal coal producer, PT Berau Coal Energy TBk, largely through cost-cutting measures.

Long-suffering minority shareholders welcomed the deal's closure. But two shareholders who didn't wish to be named called for the company to consider exiting Indonesia by either distributing Berau's Jakarta-listed shares to shareholders or selling the entire stake for cash--an option Mr. von Schirnding said the company would consider.

Asia Resource Minerals said it planned to return $400 million to shareholders as a special dividend, though the timing is unclear. Almost half of that amount will now go to Mr. Tan, who is set to be replaced as chairman by Chris Walton, currently the company's independent director. Mr. Rothschild, who owns around 16% of the company, will also be a major beneficiary of the payout.

Ian Walker in London contributed to this article.

Write to Alex MacDonald at alex.macdonald@wsj.com

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