The discovery of artifacts in a stone shelter in Western Australia’s Pilbara region could change Rio Tinto’s plans to expand an iron ore mine in the area.

The Aboriginal artifacts were found in a shelter dating back 40,000 years. The find has been described as “an abundance of flaked stone material, and faunal material including egg shell not often recovered in the Pilbara.”

The 43-square-metre rock shelter is on the edge of an area flagged to become an iron ore pit as part of Rio Tinto’s $200 million Western Turner Syncline expansion project.

In 2014, the WA Department of Aboriginal Affairs granted Rio Tinto permission to further excavate the site, guided by the Eastern Guruma people, ABC News Australia reported.

Wintawari Guruma Aboriginal Corporation spokesman Tony Bevan said the discovery was extremely exciting.

“The site's considered very rare for the region and is one of the few sites that offers the possibility or the ability to study archaeology during that whole period,” he said.

Bevan said the site has the potential to prove Aboriginal people occupied the area much earlier than was previously thought, which was around 20,000 years ago.

A report put together by consultant archaeologists said the site was in excellent condition and there was good possibility for further study to occur.

Rio Tinto said in early January it sent a draft application to “impact the site” to the Eastern Guruma, because of the potential for vibrations from mining activity to affect the rock shelter.

Bevan said due to the site’s potential world heritage value, traditional owners have asked Rio Tinto to hold off.

A Rio Tinto spokesman said they were continuing to work in accordance with the WA Aboriginal Heritage Act.

“Rio Tinto recognizes the cultural significance of this particular site and we are continuing to work with the East Guruma to identify an appropriate pathway forward,” he said.

“We are confident of finding a solution that takes account of the cultural significance of the site and our operational requirements.”