It comes after New York hedge fund Elliott went public this week with a three-pronged plan to revamp BHP, including the dismantling of the dual-listed structure, demerger of the US petroleum assets and increased buy-backs.

Mackenzie told reporters today that detailed discussions with Elliott had been going on for eight months and he was initially excited by the prospect.

“We were hoping Elliott may have found some breakthrough we missed and we could work together on some novel ideas,” he said.

“Sadly, it became clear that was not the case.”

Mackenzie said BHP had been open to Elliott’s ideas, but Elliott had been “unwilling to alter their views”.

“We continue to maintain that we have a better way to add value in a much larger quantum,” he said.

BHP completed the demerger of South32 in 2015 to create its four pillars of iron ore, copper, coal and petroleum – with potash as the potential fifth pillar.

BHP chief financial officer Peter Beaven said the company agreed that demergers could create value, but it was only at the start of the journey to create value from the new simplified structure.

The company also said it had considered spinning out all of its units to create separate pure-play businesses, but continued to favour diversification.

Mackenzie added the four pillar strategy was pressure-tested regularly and he denied petroleum was the “loosest brick in the BHP wall”, saying it had the highest margins in the past five years and the highest returns of all of its growth options.

Mackenzie said since the day he took over as CEO of BHP, he’d been repeatedly asked about the fit of petroleum in the business.

“Petroleum is a good fit with the current strategy,” he said.

“It is my view that big oil is very synergistic with big copper, big coal and big iron ore.”

Beaven also denied that the dual-listed structure was a constraint to the business.

“There’s almost nothing a single-listed company can do that we cannot.”

BHP believes implementing the Elliott proposal would cost US$1.3 billion, excluding transaction costs and any loss of franking credits.

The single listing would also disadvantage Australian shareholders and remove a form of “acquisition currency”.

Prior to BHP’s investor and media presentations today, Elliott said it appreciated BHP’s acknowledgement of the “value unlock plan” but struggled to understand the “dismissive and premature nature” of the response.

Mackenzie said the proposal had been thoroughly considered.

“It was appropriate we respond quickly and with a degree of authority,” he said.

BHP shares closed A9c lower at $25.32.