Maintenance in the mine

摘要

Production methods at the Phelps Dodge copper mine in Morenci, Arizona have come a long way since the days more than 120 years ago, when mules and brakemen were packed into narrow gauge railroad cars to coast downhill with loads of ore to a smelter at the nearby town of Clifton. The mules would later be hitched to the emptied rail cars to pull them back up to the mine. The railroad was retired some years ago. Morenci now has a system of conveyor belts that moves ore more efficiently, and smelters are no longer required because the mine employs an environmentally compatible chemical process called solution extraction /electro winning to extract 99.99 percent pure copper from the ore.