By Melanie Burton

MELBOURNE, May 1 (Reuters) - Rio Tinto RIO.AX has not modernised its agreement with an Aboriginal group on whose lands it mines iron ore, failing to fulfil a commitment made five years ago when it destroyed an important Aboriginal heritage site, the group said on Thursday.

Rio Tinto pledged to reform its business practices after it blew up the 46,000-year-old Juukan Gorge rock shelters in Western Australia in 2020 for an iron ore mine. The destruction sparked a huge public and investor outcry, a government inquiry and ultimately the exit of its CEO and chair.

Deanna McGowan of the Robe River Kuruma Aboriginal Corporation said at Rio Tinto's annual general meeting in Perth that the Mesa J mine, the company's largest on the group's lands, had been operating for 30 years.

"You have paid us for three years," she said. When Rio Tinto negotiated the agreement with the group's elders twenty years ago, executives had said there was no need to include the mine because it would soon close, she added.

"And here we're now ... 17 years of payments that Rio has cheated us at Mesa J," she said.

The lands belonging to the Robe River Kuruma group do not include Juukan Gorge but are in the same Pilbara region.

Rio Tinto Chair Dominic Barton said the company was committed to reaching an agreement on the issues raised by McGowan.

"We want to be able to get to an agreement and a resolution working with you. We've had a number of conversations and we'll be having after this meeting as well, but there is a very, very strong commitment to work through these issues with you," Barton said.

Earlier in the AGM, Barton said the mining giant had relationships with more than 60 Indigenous and land-connected groups globally.

"Many of these are very positive relationships, while a small number remain challenged," he said.

Inquiries in the aftermath of the Juukan Gorge destruction revealed that past agreements between miners and many Aboriginal groups had prevented the groups from speaking publicly about damage to their heritage and underpaid them royalties for mining on their lands.

As a result, Rio Tinto and other major miners such as BHP BHP.AX and Fortescue FMG.AX pledged to update their land-use agreements with traditional groups.

Failures by Rio Tinto to reach such agreements could disrupt its production schedule.

The miner warned in its quarterly production report that its guidance remains "subject to the timing of approvals for planned mining areas and heritage clearances."

(Reporting by Melanie Burton; Additional reporting by Renju Jose; Editing by Edwina Gibbs)

((melanie.burton@thomsonreuters.com Twitter: @MelanieMetals; +613 9286 1421; Reuters Messaging: melanie.burton.thomsonreuters.com@reuters.net))