Rio Tinto, BHP a step closer to open US largest copper mine

Rio Tinto, BHP a step closer to open US largest copper mine

The Morenci mine, in Southeast Arizona, may soon lose its status as one of North America's largest producer of copper.

Resolution Copper Co., a US-based company owned by giants Rio Tinto (ASX, LON: RIO) and BHP (ASX: BHP), is fine tuning details to submit a plan to the federal government this week, which will detail how it would run what it could be North America's largest copper mine.

Based in Arizona’s famous Copper Corridor, the Resolution Copper mine is currently in its pre-feasibility stage. The plan, to be presented to the U.S. Forest Service on Friday, is only the first step in a lengthy environmental review of the vast mine by the federal government.

According to USA Today, Resolution Copper —a 55%-45% joint venture between Rio Tinto and BHP— is expected to present a step-by-step strategy on how it plans to mine the copper ore, dispose of tailings and other waste, and bring water to the site.

The ore body the company seeks to mine is a deep-seated porphyry copper deposit located under the now inactive Magma Mine. Rio has reported an inferred resource of 1.624 billion tonnes containing 1.47 per cent copper, at depths exceeding 1,300 metres.

BHP Billiton bought Magma Copper in 1996 for $3.2 billion. The group’s San Manual copper smelter in Arizona was considered to be the jewel in the crown, but barely three years later BHP was forced to put it on care and maintenance and then shut it down completely in 2003.

Closure costs added another $800 million to the world’s number one miner’s most disastrous acquisition to date. Rio Tinto became the joint venture partner on Resolution Copper as a result of these write-offs.

Since 2005 Resolution Copper has been trying to arrange a land swap deal with the federal government to start mining. So far, eleven versions of a land-exchange bill have been introduced in Congress.

If approved, the mine is expected to create 3,700 direct and indirect jobs and bring $61.4 billion in economic benefits to Arizona.

Copper output from the mine, to begin production in 2021, is projected to meet 25% of the internal demand.

Image from WikiMedia Commons