Global miner BHP Billiton unveiled a board shake-up where controversial director Grant King will step down just six months after his appointment with the company amid oil investments concerns, BHP said on Aug. 23.

King, former CEO of Origin Energy, was once tipped to succeed Jac Nasser as chairman of the world's biggest mining company, but was passed over earlier this year for fellow board member Ken MacKenzie.

“Owing to concerns expressed by some investors, Grant King has decided that he will not stand for election at the 2017 annual general meetings of BHP and will retire from the board on August 31,” Nasser said.

BHP's stock (NYSE: BBL) was trading about a half-percent higher at AU$26.55 (US$ 20.96) a share at 11:00 a.m. CT, in a weaker overall market, having also risen on Aug. 22 after its full-year results.

BHP is under pressure from investors led by hedge funds, Elliott Management and Tribeca Investment Partners, to rethink its investment in oil and boost shareholder returns. The company said on Aug. 22 it would exit its underperforming U.S. shale oil and gas assets.

Tribeca, which in May called for a sale of BHP's shale assets, a return of capital, and a board and management revamp, welcomed the board changes.

"We would like to see more of it for this company in coming quarters," said Craig Evans, the co-portfolio manager of the Tribeca Natural Resources Fund.

Elliott declined a request for comment.

King oversaw dramatic growth at energy retailer Origin during a 16-year stint as managing director. However, a decision to build a AU$25 billion (US$19.7 billion) LNG plant led to a plunge in the Origin's share price in 2015 when oil prices plunged just as its debt peaked.

BHP unveiled the board changes a day after reporting a surge in underlying annual profit to $6.7 billion. At the same time it sought to reassure investors it would allocate future capital with caution and use excess cash to cut debt and reward shareholders.

Another director, Malcolm Brinded will not to stand for re-election as a non-executive director, BHP said.

BHP named Terry Bowen, a finance director for Australian retail and mining conglomerate Wesfarmers Ltd., and John Mogford, a former BP executive, as the two new independent non-executive directors.

The pair will take up their roles on Oct. 1.

MacKenzie has spent the past two months sounding out shareholders ahead of his Sept. 1 start date, BHP said.

"It generally starts at the board level for a good company and I think BHP's was under-experienced in the space and not focused enough on the job of being board members for a company of this size and complexity," Evans said.

"One of the reasons we supported Ken [MacKenzie] without hesitation is that he has very few obligations outside of this role."