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AZ Copper Miner Draws Ire for Block-cave Method

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Copper prices are rising, and Arizona, with its ample reserves, is high on miners’ lists of places to excavate.

One such project, though it could become the nation’s largest copper mine, is drawing resistance from conservation and Native American groups for a variety of reasons, the Washington Post reports. It's a land swap proposed by Resolution Copper Mining that would enable the company to extract the ore that’s buried 7,000 feet underneath 2,400 acres in the Tonto National Forest.

In return for ownership of this 2,400 acres, Resolution Copper is offering the public 5,500-plus acres of land it owns that are scattered around the region, the newspaper said in a January 2 story. A map of the lands in question from Arizona Geology, the blog of the state geologist of Arizona, is here.

Though it is opposed by some environmentalists and Native American groups, the project is the subject of legislation that includes an authorization of the land swap. The omnibus bill to which it was attached was scuttled at the end of the last Congressional session, but similar legislation could very well be passed this year, the Post said.

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Resolution Copper would use the block-cave method, in which explosives are set off below the ore body, creating a space underneath and allowing the ore to collapse from its own weight, after which it’s extracted. Opponents fear the method could damage Native American sacred lands, among them the historical Apache Leap, where tribal warriors leaped to their deaths rather than surrender to Arizona soldiers, according to historical accounts like this one.

In addition the Arizona hedgehog cactus, an endangered species, also resides on the land, which is also a hot spot for rock climbing and other tourism activities.

Royal Copper, a subsidiary of Rio Tinto and BHP Billiton, says this could become the U.S.’s largest source of the ore, yielding 500 million tons annually, which is one fifth of the country’s national demand for the next 50 years. The company said it would also employ 1,400 people during peak operation, according to the Post, with a net economic impact of $46.4 billion over the mine’s 66-year lifespan.

Economically the idea is enticing given a report in the Arizona Daily Star noting that the current copper resurgence is caused by an increase in prices globally—copper rose to $4.40 per pound during the last two weeks of 2010, up from $1.33 in 2008. Some forecasters predict a shortage of the metal next year, the Star said, which could push prices up as high as $5 per pound over the next one to three years.