Rio Tinto has admitted it did not tell traditional owners there were four options for blasting at Juukan Gorge, three of which did not involve the destruction of highly significant ancient rock shelters.

It also said senior executives were only made aware of its significant issues more than a week after tonnes of explosives were already laid in the area comprising the Brockman 4 mine and were unable to be removed.

Traditional owners were "deeply troubled" after Rio Tinto detonated explosives near culturally significant rock shelters dating back more than 46,000 years, destroying them, on the weekend of 23-24 May this year.

Executives from the company have testified at the first day of hearings in a federal parliamentary inquiry investigating Rio Tinto's destruction of the rock shelters in WA's Pilbara.

The destruction has damaged Rio Tinto's relationship with the Puutu Kunti Kurrama people and the Pinikura (PKKP) traditional owners, and its international reputation.

"The PKKP was not made aware that four options were available in 2012 and 2013," Rio Tinto CEO Jean-Sebastien Jacques told the hearing.

"At the relevant meeting in 2013, only one option was presented to the PKKP — and that was the basis of the submission for the section 18."

The destruction was legal under the section 18 exemption to WA's Aboriginal Heritage Act, which is currently being reformed.

That option was the one adopted and carried out in May.

It gave Rio Tinto access to an extra eight million tonnes of high grade iron ore, estimated to be worth $135 million at the time.

Mr Jacques said no employee had been dismissed or suffered a financial penalty over the blasts.

Executives unaware of significance until May

The cave sites were among the oldest in Australia with evidence of continuous human habitation going back 46,000 years.

The inquiry heard senior executives only became aware of the issue on May 21, and were not aware of the area's high cultural significance until then.

This was despite a number of archaeological reports funded by the company since 2013.

The hearing was told "the point of no return" for the blasting was May 13 when hundreds of charges were laid at the site.

Rio Tinto's CEO of iron ore Chris Salisbury said "it was obvious" the company could not remove the 66 tonnes of high explosives already laid.

However, in a 10-hour operation on May 23, it did manage to remove seven charges to prevent the destruction of other sites of significance identified by the PKKP further down the gorge.

CEO extends another apology

Mr Jacques again apologised for the destruction and said it should not have happened.

He said the company had avoided extracting 380 million tonnes of iron ore over the past five years due to heritage or environmental concerns.

"We are absolutely sorry for what happened," said Mr Jacques, who relocated from London to Sydney when the COVID-19 outbreak occurred.

WA Aboriginal Affairs Minister Ben Wyatt, who is currently reviewing the state's Aboriginal Heritage Act, said boards of major mining companies should have a better connection with the place they make most of their money.

He said senior executives came and went with no deep connection with the broader WA community, and in particular the Pilbara.

"I think that vast distance between boards and the place in which they make their own money is becoming a real risk for some of these organisations," he said.