Rio Tinto said the expansion work for its Brockman 4 iron ore mine in Juukan Gorge in the Pilbara region of Western Australia was conducted under a 2011 native title and heritage agreement with the Puutu Kunti Kurrama and Pinikura, or PKKP, traditional owners.

The company destroyed a sacred site in Juukan Gorge as part of the expansion, The Guardian (Australia) reported. The cave, located at the Hammersley Ranges, is the only inland site in Australia that showed continuous human occupation for 46,000 years. Artifacts included a 4,000-year-old length of plaited human hair, which DNA testing concluded came from the direct ancestors of living Puutu Kunti Kurrama and Pinikura.

Rio Tinto noted that it obtained ministerial consent in 2013 under section 18 of the Aboriginal Heritage Act after consultation with the PKKP people and undertook "extensive heritage preservation and salvage work" in 2014 together with the PKKP.

"We have continued to work closely and collaboratively with the PKKP on a range of heritage matters, including operations in the Juukan area, and have modified our operations to avoid cultural and heritage impacts," the company said May 27.

Rio Tinto deposited the preserved artifacts at its storage facility, with PKKP's approval, to protect the material, and said it is reviewing longer-term options with the PKKP.

"We are sorry that the recently expressed concerns of the PKKP did not arise through the engagements that have taken place over many years under the agreement that governs our operations on their country," the company said in a statement.