Traditional owners were not informed Rio Tinto had examined mining options that would have avoided the destruction of the sacred Juukan Gorge caves.
Rio Tinto officials have fronted a Senate hearing examining the mining company's blasting of the ancient and culturally significant 46,000-year-old sites in Western Australia’s Pilbara region.
The destruction of the caves lead to widespread public outcry, and calls from Indigenous groups for better protection of heritage sites in Western Australia.
The inquiry heard the multinational mining company had three options to expand its Brockman 4 mine without damaging the Juukan Gorge sites but chose a fourth option for economic gain.
“The difference between option four and the other three options was 8m tonnes of high grade iron ore,” CEO Jean-Sebastien Jacques told the hearing.
“The economic value was around $135m of net value at the time of the decision.”
Mr Jacques confirmed traditional owners the Puutu Kunti Kurrama and Pinikura people (PKKP) were not informed about options that would have saved the site.
“That is absolutely correct … the PKKP was not made aware that four options were available," he said.
"Only one option was presented to the PKKP."
Liberal MP Warren Entsch, the chair of the joint standing committee on Northern Australia, said the admission was disturbing and questioned how traditional owners could give 'free, prior and informed' consent without knowing about the other plans.
"That really bothers me," he said.
"It really beggars belief ... that there was no understanding by the executive within Rio that there was an issue on this site."
In a submission to the inquiry, Rio recognises a failure to clearly communicate the timing of the operation with traditional owners, who were left shocked once discovering plans for the blasting.
The mining company has repeatedly apologised for the sites destruction in May, calling the incident a “mistake”.
It has also admitted to failure to take repeated chances to intervene to avoid the caves being destroyed.
But Mr Jacques claimed he only learned of the significance of the Juukan Gorge rock shelters days before they were blown up.
He said a 2018 archeological report that warned of the high significance was not read by any of Rio's executive leadership team.
"We are absolutely sorry for what happened," he said.
"I can put my hand on my heart and say there is no one at Rio who wakes up in the morning and wants to do harm to Aboriginal heritage sites."
The mining company which had legal approval to blast the Juukan Gorge site, said it believed it had the consent of traditional owners.
It reached a development agreement with the PKKP people going back to 2011.
Rio also conducted an ethnographic survey and archaeological excavations of the rock shelters determining cultural significance in 2013 and 2014.
The 2018 report received by Rio revealed the existence of 7000 artifacts including grinding stones, tools and 4000-year-old braided hair.
Another point of contention was whether Rio had an opportunity to remove the explosives after learning the PKKP were against the blasting going ahead.
The inquiry heard by the time PKKP representatives learned the caves would be destroyed, blast holes had already been loaded with explosives.
Rio's iron ore chief executive Chris Salisbury said attempts were made to remove a small number of explosives, but the company could not remove all of them safely to prevent the destruction going ahead.
The WA government has admitted current protections under state’s Aboriginal Heritage Act, which gave approval for the blasting at Juukan Gorge aren’t adequate, and has pledged to amend the legislation this year.
"The principals underridding the Aboriginal Heritage Act in Western Australia are woefully inadequate and no one is disputing that,” WA Indigenous Affairs Minister Ben Wyatt told the hearing.
“I’m hoping the new act will establish better principles and elevate the Aboriginal groups in managing heritage.”
Mr Jacques said no one at Rio Tinto had been stood down or suffered financial consequences saying blame couldn't be placed on a single person for the company's mistakes.
He said an internal review into the incident is underway.
The committee has requested that Rio Tinto appear again at the inquiry.