London - Financier Nathaniel Rothschild and a member of Indonesia’s Bakrie family were involved in an angry exchange on Twitter after they completed a long-delayed $501 million deal to unwind a three-year-old joint coal investment.

The public spat came in a series of messages yesterday between Rothschild, 42, the scion of a centuries-old British banking dynasty, and Aga Bakrie, son of one of three brothers who control the family empire.

Earlier in the day it was announced that the Bakries had severed their ties with London- based Asia Resource Minerals Plc.

Rothschild thanked the Bakries for buying back coal assets he described as “worthless.”

Aga, son of Nirwan Bakrie and executive vice president of Bakrie Capital Indonesia, countered that Indonesia is “an amazing investment haven.”

In other tweets, they described each other as “dumb.”

Relations between Rothschild and the Bakries have been strained over their ill-fated $3 billion investment announced in 2010 that created Bumi Plc, later renamed Asia Resource Minerals.

Yesterday marked “a pretty critical turning point in the company’s fortunes with closing that unfortunate chapter,” Asia Resource Minerals chief executive Nick von Schirnding said in an interview in London.

He said the Bakries will play no role in the company after the separation.

The Twitter exchange isn’t the first time both sides have openly attacked each other.

The Bakries have previously described Rothschild as a “disappointment.”

In July Rothschild called the deal for the family to extract themselves from Asia Resource Minerals a “choreographed stitch-up between the Bakries” and Chairman Samin Tan.

‘Move On’

Rothschild “is obviously entitled to his views,” Von Schirnding said in the interview.

“We have disagreed on whether this transaction was doable and we sit here today with $501 million for the benefit of all the shareholders. We move on.”

Asia Resource Minerals plans to return more than $400 million to investors, or about 103 pence a share.

“I look forward to nominating an independent director to strengthen the Plc board as agreed in December,” Rothschild said yesterday in an e-mail.

“I expect this to be concluded in the days ahead.”

The separation deal, hampered by slumping coal prices and declining share values, was originally proposed by the Bakries in October 2012.

It was then delayed repeatedly as the family sought funding.

Presidential Candidate

The complex transaction involved the Bakries buying back from Asia Resource Minerals a 29 percent stake in coal exporter PT Bumi Resources.

Tan also bought 24 percent of Asia Resource Minerals from the family for $223 million through his PT Borneo Lumbung Energi & Metal, increasing his shareholding to 48 percent.

The deal leaves Asia Resource Minerals with control of another coal producer, PT Berau Coal Energy.

The Bakries are among Indonesia’s most powerful families, with business interests from commodities to real estate and media.

Aburizal Bakrie is chairman of Indonesia’s second-biggest political party and a candidate in the presidential election to be held in July.

Completion of the deal should allow Bumi Resources to complete a delayed $1.3 billion debt swap with China Investment Corp. shortly, Bakrie Group spokesman Chris Fong said yesterday.

Bumi Resources, Indonesia’s biggest coal exporter, will now be able to make progress with other investments that were constrained by the delay, he said.

Asia Resource Minerals advanced 3.3 percent to 237.5 pence yesterday in London, the highest in more than a month, valuing the company at 572 million pounds ($946 million). - Bloomberg News