The head of Rio Tinto’s iron ore division said he has “taken accountability” for the destruction of a 46,000-year-old Aboriginal heritage site but refused to give a direct answer when asked if the company knew traditional owners did not want the rock shelter destroyed, saying: “clearly, there was a misunderstanding”.

In an interview on Radio National on Friday, the chief executive of Rio Tinto iron ore, Chris Salisbury, said it it had “taken accountability” for the destruction of the site, which was one of two destroyed in a blast to expand the Brockman 4 iron ore mine last month. 

The two sites were located in Juukan Gorge in the Hamersley Ranges, about 300km inland from Karratha in Western Australia’s iron ore rich Pilbara region.

Traditional owners the Puutu Kunti Kurrama and Pinikura people only learned of the planned detonation on 15 May, nine days before it took place. They said the loss was “soul destroying”.

Salisbury said the company “regrettably … thought we had a shared understanding with the PKKP about the future of the sites” and would conduct a review to learn “how did this go wrong from our point of view”.

He also refused to provide a direct answer when asked if a statement released by the company last week, which suggested the PKKP had only “recently expressed concerns” about the site, was incorrect. It released another statement apologising “for the distress we caused” but not the destruction, on Sunday.

“We can’t keep looking backwards,” Salisbury told interviewer Hamish Macdonald. “We want to repair our relationship with traditional owners.”

That review, which is being conducted with oversight from the Rio Tinto board, will not be released publicly but will form the basis of a submission to the West Australian government on the proposed reform of the Aboriginal Heritage Act 1972. 

Rio Tinto received ministerial consent under section 18 of that legislation to destroy two rock shelters in Juukan Gorge. Consent was granted by the then minister for Aboriginal affairs in Western Australia in 2013, one year before an archeological survey, approved by Rio, found the site was of high archeological significance and showed signs of human occupation dating back 46,000 years, including throughout the last ice age. It’s the only known site in inland Western Australia to show that continued occupation. 

The 2014 survey was a salvage mission that gathered more than 7,000 artefacts, including a plaited belt made from human hair that DNA testing revealed belonged to the direct ancestors of PKKP alive today, and tools and grinding stones which showed those tools had been in use far earlier than archeologists previously believed. The artefacts remain in Rio Tinto’s possession.

Salisbury initially said he did not know their exact location, saying “I don’t think that’s important”, then said they were held on site at Brockman 4. 

Salisbury said Rio Tinto had been working “very, very closely” with the PKKP since 2003 and he had “taken accountability that there clearly was a misunderstanding about the future of the Juukan Gorge”. He said the company would “overhaul” its heritage process and take a “leadership position” on the reform of the Aboriginal Heritage Act, which has been under way since 2018.

“The findings of the review as they are relevant to WA legislation, then we will advocate on their behalf to ensure this does not happen again, certainly not at one of our sites, but also more importantly to raise the bar for industry,” he said.

The Australian Greens have called for Salisbury to be sacked. 

Rio Tinto has already made a submission to the current review of the legislation. In a 2019 submission to a consultation paper, it said it supported the repeal but that reform should not “introduce uncertainties or disruption to the implementation of existing agreements”. 

It said that if traditional owners are granted the right to appeal decisions to destroy heritage there should be clear, fixed timelines “rather than broad appeal rights that may be used to prolong approvals or appeals at a critical point for a project”.

Burchell Hayes, a traditional owner and director of the PKKP Aboriginal Corporation, told the ABC that information provided by Rio Tinto in meetings with traditional owners, including about developments that would have a direct impact on heritage sites, was “sometimes … at a level that a lot of our people cannot understand”.

Lawyers for the PKKP wrote to the federal Indigenous affairs minister, Ken Wyatt, with an eleventh hour plea to save the site and were advised to contact the environment minister, Sussan Ley, to request she intervene on heritage grounds. The federal powers to stop the destruction of Aboriginal heritage are rarely used.

Hayes said that Lees’s office was yet to return a call from PKKP lawyers.

“It is [disappointing] because now it’s far too late, it’s already happened,” he said.

Hayes said the destruction of the two sites was so distressing that he was not prepared to tell one of the PKKP elders, who lives near him in Onslow on the Pilbara coast, about the loss.

“I don’t have the strength to go and tell her what’s happened … because she’s very elderly it’s not a conversation I want to go and have with her,” he said. “That’s her father’s country. We named that gorge after her father, my grandfather.”