Rio Tinto has destroyed a significant Aboriginal site dating back 46,000 years.

Rio detonated explosives in WA’s Juukan Gorge last Sunday, destroying two ancient rock shelters held sacred by the Puutu Kunti Kurrama and Pinikura people.

The mining giant was operating on a approval for work at the Brockman 4 iron ore project in 2013, despite archaeological excavation revealing ancient artefacts including grinding stones, a bone sharpened into a tool and 4000-year-old braided hair in 2014.

When outrage first erupted, Rio suggested that Aboriginal representatives did not make their concerns about preserving the site clear.

Puutu Kunti Kurrama and Pinikura Aboriginal Corporation (PKKPAC) spokesperson Burchell Hayes labelled the claim outrageous, saying Rio knew of the significance of the rock shelters, and had told the PKKPAC that it had no plans to extend the Brockman 4 mine.

“The high significance of the site was further relayed to Rio Tinto by PKKPAC as recently as March,” Mr Hayes said.

He said the corporation only found out about Rio’s intention to blast the area “by default on May 15 when we sought access to the area for NAIDOC Week in July”.

The mining giant has apologised.

“We are sorry for the distress we have caused,” Rio Tinto Iron Ore chief executive Chris Salisbury said in a statement on Sunday.

“Our relationship with the PKKP matters a lot to Rio Tinto, having worked together for many years.

“We will continue to work with the PKKP to learn from what has taken place and strengthen our partnership.

“As a matter of urgency, we are reviewing the plans of all other sites in the Juukan Gorge area.”

The WA Government said it did not know anything about the blast or and concerns beforehand.

Still, the state is working on a new Aboriginal cultural heritage bill.

“It will provide for agreements between traditional owners and proponents to include a process to consider new information that may come to light, and allow the parties to be able to amend the agreements by mutual consent,” WA Aboriginal Affairs Minister Ben Wyatt said.

“The legislation will also provide options for appeal.”