The New Bronze Age: Copper Demand Will Outpace Mine Supply

http://www.psmag.com/environment/the-new-bronze-age-entering-the-era-of-tough-ore-60868/

In 2001, the giant mining firm Rio Tinto made a momentous decision: Its Bingham Canyon Mine—the oldest and richest open-pit copper mine in the world, in operation since 1906 and the largest man-made excavation in history—would be shut down.
Since the early 1980s, the copper industry had been in a prolonged slump. As Europe and North America shifted from manufacturing to service economies, demand for copper flatlined and its price stagnated. Mine operators were making cents on the dollar. Bingham—a huge crater in the heart of the Oquirrh Mountains, 20 miles from Salt Lake City—was at a tipping point. To keep producing, the pit would have to keep expanding, and each expansion would be more expensive than the last. Eventually, the costs would outweigh the returns. Closure of the pit was slated for 2013. It would be the end of an era.
That end did not come. If you visit Bingham Canyon today, you’ll find a fleet of house-size dump trucks descending into the pit, loading up on rock, and climbing back up and out, around the clock. The pit is being widened and deepened to expose new ore, even as current mining operations continue.
But the pit is not the whole story. Rio Tinto is planning to build a second mine on—or rather, under—the site. The aboveground operation will now be shut down around 2029. But Bingham Canyon is likely to go on. According to the current plan, the giant pit will give way to a giant underground mine, already in the early stages of construction, 2,000 feet beneath the pit’s floor.