"ACCR is currently engaging with Rio Tinto on the issue of trade associations like the MCA. Rio's investors have similar concerns to BHP's, about the risks to shareholder value that flow from of misaligned trade association advocacy on climate and energy policy issues. We are pleased Rio Tinto is willing to engage on this issue," she said in a statement.

Rio's board of directors will front London shareholders on April 11 before facing Australian shareholders in Melbourne on May 2.

Rio has divested most of its coal assets in recent years, and is believed to have held similar concerns to BHP about the MCA's approach to advocacy on energy and climate in recent years.

The MCA campaign was one of two motions the ACCR put before BHP's annual meeting of shareholders in November 2017, with the other motion designed to allow shareholders to make advisory recommendations to directors.

Just over 9 per cent of BHP shareholders supported the ACCR's motion on climate change advocacy, while closer to 7 per cent supported the advisory recommendations resolution.

The MCA's interim chief executive David Byers sought to clarify the relationship between the lobby group and BHP in an interview last week.

"The difference hasn't been about the promotion of coal, the difference has been about some technical aspects if you like in climate and energy policy," he told ABC Radio on January 23.

Mr Byers rejected the suggestion that his predecessor, Brendan Pearson, had been ousted as chief executive of the Minerals Council because BHP was unhappy with his advocacy on coal fired power.


Whitehaven Coal chief Paul Flynn said on January 18 the MCA had not deserved any criticism over its coal advocacy, saying it was logical for the organisation to spruik coal's role in the energy mix.

World Coal Association chairman Mick Buffier expressed concerns in December that his organisation's policy platforms had been misrepresented in BHP's review.

BHP has made a preliminary decision to quit the World Coal Association, and is expected to clarify that decision before March 31.

The miner will decide by the end of 2018 whether it wants to continue as a member of the MCA, after contributing 17 per cent of its membership revenue in 2016.