Rio Tinto, which has state government approval to damage the site, told the Wintawari Guruma people, its traditional owners, of its intention to preserve the rock shelter last week, although the Wintawari say they have yet to receive confirmation in writing.

"We will protect the site and also have mining buffer zones in place to further ensure the site is not at risk," the world's largest iron ore miner said in an e-mail in response to Reuters questions about the site.

The state government-approved detonation in May of caves in the same region that showed evidence of human history stretching back 46,000 years provoked worldwide condemnation and has triggered government and internal reviews.

Since then, Australia's biggest iron ore miners - Rio Tinto, BHP and Fortescue Metals Group - have been reviewing heritage sites that could be affected by mine expansions, although they have resisted calls for a complete moratorium on sites for which they have been granted exemptions to disturb or damage.

The 43,000-year old rock shelter was highlighted in a March 2018 report by Scarp Archaeology as having "high archaeological significance", which also noted the Silvergrass East area was "likely to feature more locations of extensive antiquity."

Despite the findings of the report, Rio Tinto applied the following April to damage the site, called SG-07-22, and consent was granted by the state government's Minister for Aboriginal Affairs in an Aug. 15 2019-dated document that was obtained by Reuters.

"Nobody at Wintawari is ever happy to see any sites destroyed - hopefully Rio is also coming around to that point of view," said Kathryn Przywolnik, heritage manager for the Wintawari Guruma Aboriginal Corporation.

"This could be a sign of Rio reviewing its decision-making process but it's a bit early to tell."

Since July 2010, miners have submitted more than 460 applications to disturb or destroy sites of potential cultural significance in the region, according to Western Australia state parliament records. All but one of those applications were approved.

The May blasts of the sacred caves, whose traditional owners are the Puutu Kunti Kurrama and Pinikura people, highlighted the power imbalance between miners and Indigenous Australians who have no legal veto over development projects on their ancestral land.

Unlike their title suggests, traditional owners don't own the land and are only sometimes considered stakeholders in its management.

An Australian federal government inquiry that began in June has exposed controversial clauses in miners' contracts with traditional owners that prohibit them from publicly objecting to site destruction and that may also impede their rights under other Australian legislation.

Rio Tinto executives are due to give further evidence before the inquiry from late next month.

The outcry over the May blasts also became one facet of the Black Lives Matter protests in Australia, where Aboriginal groups have long suffered higher rates of imprisonment, unemployment and lower life expectancy.

By Melanie Burton