Rio Tinto did not tell traditional owners blowing up Juukan Gorge site was just one option for mine

Rio Tinto did not tell traditional owners that it had the option of not blowing up significant cultural heritage sites in the Juukan Gorge and the company’s senior executives were not aware of the significance of the site until after it was destroyed, a parliamentary inquiry has heard.

Two rock shelters in Juukan Gorge in the Pilbara region of Western Australia were blown up in the expansion of one of Rio Tinto’s open-cut iron ore mines, dubbed Brockman 4, on 24 May.

One of the rock shelters showed evidence of 46,000 years of continual occupation and was classified by an archeologist hired by Rio Tinto to survey and salvage the sites to be of the “highest archeological significance” in Australia.

Related: Rio Tinto blew up Juukan Gorge rock shelters 'to access higher volumes of high-grade ore'

Rio Tinto had approval under s.18 of the Western Australian Aboriginal heritage legislation to blow up the sties, but the destruction sparked global outrage and is the subject of a federal parliamentary inquiry

Rio Tinto chief executive, Jean-Sébastien Jacques, said the company reviewed four possible options for the design of the Brockman 4 mine pit in 2013 and 2012, three of which would have avoided damage to the site.

“The difference between option four and the other three options was 8m tonnes of high grade iron ore,” Jacques said. “The economic value was around $135m of net value at the time of the decision.”

That amounts to about 2.5% of the volume of Rio Tinto’s total iron ore production in the Pilbara last financial year.

Asked when the traditional owners, the Puutu Kunti Kurrama and Pinikura peoples (PKKP) were made aware of the other options, Jacques said: “The PKKP was not made aware that four options were available in 2012-2013, and at the relevant meeting in 2013 only one option was presented to the PKKP.”

Labor MP Anika Wells asked: “They were not made aware that there were three other options that did not involve the destruction of the caves?”

“That is absolutely correct,” Jacques said.

The inquiry chair, Liberal MP Warren Entsch, said that admission called into question Rio’s claim that it had negotiated an agreement with the PKKP which included their free, prior and informed consent to damage the sites.

“Their informed consent,” Entsch stressed. “There is an admission that it was conveyed to the PKKP that there was only one option … that really bothers me.”

The PKKP signed a series of agreements with Rio Tinto, dating back to 2006, which included a clause that they would not oppose s.18 applications provided Rio Tinto made “all reasonable endeavours” to minimise impact. The agreement also has confidentiality clauses, and the minister for northern Australia, Matt Canavan, sought an assurance from Rio Tinto that it would not pursue legal action against the PKKP if it were to breach those confidentiality agreements by giving evidence to the inquiry.

The PKKP has not yet made a public submission to the inquiry.

Jacques told the inquiry on Friday that he was first informed of an “issue” around the planned blast of the Brockman 4 mine on Thursday 21 May. But he said he was not made aware of the “significance” of the site until the evening of 24 May, after it had been blown up, when he saw a draft press release from the PKKP.

Brad Haynes, Rio Tinto’s vice president corporate relations Australia , said he read the “summary details” of the 2018 archeological report on the week of 20 May, once the PKKP had raised issues about the significance of the site, but had not read it prior to that week.

Haynes said no member of Rio Tinto’s senior executive was aware of the significance of the caves prior to the blast. The site had been surveyed three times at Rio Tinto’s expense, most recently in 2014, when a report by Slack archeology noted it was a site of extremely high cultural significance.

A formal report on its significance was provided to the company in 2018, which they passed on to the PKKP. But senior executives did not read that report.

Related: Expansion of Pilbara mine threatens 60,000-year-old sacred site, inquiry hears

“At no point during this period, up until May of this year, no one in your executive team was aware of the implications of mining this site?” Labor MP Warren Snowdon asked.

Haynes said: “Yes, Mr Snowdon, and that’s because we were always operating on the basis that there was consent.”

Rio had drilled 382 blast holes and filled them all with 66 tonnes of explosives and detonators by 13 May. The PKKP became aware of the planned blast the next day, and by 20 May had written to the federal minister requesting urgent intervention.

Chris Salisbury, the chief executive of iron ore, said that the company’s own blast experts and independent explosives consultants told them that “removing the blast might be difficult and have extensive safety risks”.

He said he was made aware of the issue on 21 May, and “was aware there was significance of the site which was conveyed to us via email … but I was not aware of the archeological report at that point”.

The company did spend 10 hours trying to remove the explosives from eight drill holes, and succeeded with seven – but that effort was made because the PKKP flagged a possible risk to heritage sites that were not subject to s.18 approval.

Rio Tinto has now apologised at senior levels for the blast, and Jacques led with another apology on Friday. LNP MP George Christiansen asked whether this was genuine sorrow, or sorrow over the incident making the news. “Because this was known,” he said. “Do you accept that, that this was a known thing that at any stage Rio could have made another decision on?”

Jacques said that “the destruction of the rock shelter should not have happened and we are absolutely sorry for everything”. He said the company’s actions were “simply not sufficient”.

He said that, to date, no financial penalties have been issued against any individual staff member, and no individual staff member has been reprimanded or counselled.

But he disputed a claim made by his predecessor, Sam Walsh, who told the Australian Financial Review that he issued instructions that the Juukan Gorge not be damaged. Walsh was chief executive when Rio Tinto applied for and received permission to destroy the site.

“We couldn’t find any communication referred to by Mr Walsh from the press this morning,” Jacques said.