The first copper mine to be commissioned in the United States in nearly 30 years is in its last stages of construction and preparation and Metso Minerals equipment will play a large role in the processing plant on site.
The Safford Mine is located outside of Safford, Ariz., northeast of Tucson. The mine, which will be commissioned late this year, will produce 240 million pounds per year of copper cathode through a heap leach process. The production plant is designed to process 114,000 tons of crushed stone each day from which the copper will be extracted.
All the crushers, screens and feeders at Safford's primary, secondary and tertiary plants are supplied by Metso Minerals.
In the primary plant, stationary and vibrating grizzlies as well as apron feeders help direct oversized material to the primary crusher, a Nordberg C160 jaw crusher which can process from 680 to 960 short tons per hour. This unit crushes plus-12-inch material which is then conveyed to the secondary and tertiary crushers.
At the heart of the plant are six MP1000 cone crushers. "Many different iterations of the plant flow were simulated and different scenarios considered in concert with the Phelps Dodge project team until the final flowsheet and plant design was developed and agreed on by all involved," says Ivan Pavlovic, Metso vice president of capital projects and global crushing sales.
Dave Ogonowski, senior project manager for Phelps Dodge Mining Co., says these crushers were selected because of a number of factors including robust design, higher installed power and reduction capabilities while operating in open circuit, but ultimately for their ability to meet production demands. Two units will act as secondary crushers and four will be tertiary crushers.
"After various options were explored from an engineering basis, it was decided that the project would include MP1000 crushers," said Ogonowski, who was responsible for engineering procurement, construction and commissioning at the mine site. "Metso was super in providing technical information and worked with us exceedingly well through the acquisition and construction process."
Metso Minerals also provided the screens for the processing plant. Two 12-foot by 27-foot double-deck Multi-Flo screens are used in the secondary plant and four 12-foot by 27-foot single-deck screens are used in the tertiary plant. These screens were chosen mainly for their size, said Ron Kuehl, Metso Minerals' product manager for mining screens. "Phelps Dodge needed a heavy, substantial machine to handle the expected capacity of 3,600 tons per hour," said Kuehl. With isolation frames and dust enclosures, each of the double-deck screens weighs 115,000 pounds.
Phelps Dodge has also placed orders for one spare feeder, a double-deck screen and a single-deck screen as well as the necessary supply of spare parts to maintain top efficiency and equipment utilization at this plant.
Key to the success of this equipment installation was Metso's ability to provide early delivery of production machines. While, according to Ogonowski, the goal was to commission this plant earlier than the expected 2008 launch date, Metso played a key part in allowing that to happen.
"Metso was very flexible in terms of locking in production slots with us and doing it with the minimal amount of commitment on our part," said Phelps-Dodge's Ogonowski.
While improved commission date has not yet been determined, the mine will be producing copper earlier than originally scheduled.