It comes after the two signed a memorandum of understanding in March.

The HoA sets out the principles and framework for a potential exploration collaboration, inside and outside China.

“Minmetals is rapidly becoming an important player in the global mining industry and we look forward to partnering with them,” Rio chief executive J-S Jacques said.

“Our complementary strengths in exploration across the globe put us in the best possible position to find the metals and minerals that are essential to our modern lives.”

China Minmetals Corporation chairman He Wenbo said Rio was a leading global mining group that had accumulated tremendous exploration experience and success over time.

“Minmetals is a fast growing company and the partnership with Rio Tinto will help secure mutual global opportunities for quality resources and enhance our long-term development in the mining sector,” he said.

The two companies will now work to formalise written agreements detailing the principles and other matters relating to its implementation and to establish joint teams to start the process of identifying targets for potential exploration collaboration.

The deal comes after a five-year exploration partnership with Chinalco ended last year, but the company said it had maintained a presence in China to evaluate new opportunities and partnerships.

In its 2016 annual report, Rio boasted of one of the largest exploration programs in the industry.

Last year, the company was active in 14 countries across copper, nickel, iron ore, bauxite, coking coal, uranium, diamonds and mineral sands and established joint ventures in the US, Chile, Australia, Serbia, Kazakhstan, Papua New Guinea and Mexico.

The company has spent US$1.7 billion on greenfields exploration over the past decade, including $496 million last year.