Large Copper Mine

Overview

A mine property in Arizona in the United States covers approximately 60,000 acres and has five pits, with several still currently active. It is the largest copper mine in North America and one of the largest in the world. The mine has a workforce of approximately 2000, processing up to 700,000 tons of rock per day, producing up to 840 million pounds of copper per year. Only Chilean company Codelco is bigger in world copper production.

Copper Extraction

Copper is extracted using the SX-EW, or solution extraction-electrowinning, process. The process involves leaching the ore with a weak sulfuric acid solution, concentrating the solution (SX process) and then collecting the copper from the solution by electrowinning (EW process). In the EW process the copper is reduced electrochemically from copper sulfate in solution to a metallic copper cathode. Electrowon copper cathodes are as pure, or purer, than more conventional electrorefined cathodes from a smelting process.

This process also allows recycling of the leaching solution which greatly reduces environmental impact, as the SX process returns the solution to its original acidity thereby allowing it to be recycled for leaching. The SX-EW process also makes it possible to extract copper from low-grade sulfides. There are four solution extraction facilities and three electrowinning tankhouses with by-products are silver, gold and molybdenum.

The mine operations also pioneered the use of wireless networking technologies including GPS to manage equipment and production.

What We Did

We have worked with Phelps-Dodge and successors for several years developing their mine safety monitoring system. Prior to our involvement with the project the monitoring consisted of several disconnected systems for different types of instruments with no centralized dispatch of alarms to the operations group. Our involvement has facilitated combining all of the automated monitoring into a single database using our MLDB software, MLWeb® is also utilized to present the alarm monitoring interface to dispatch and other operations personnel.

Database Integration

We have worked with them to integrate their Leica Total Stations (TPS), dewatering well monitoring, slope monitoring using wire extensometers, MFL leaching levels, flow monitoring and two Campbell Scientific weather stations. All mine-wide communications are facilitated using a high-bandwidth Mesh wireless TCP/IP network, we are also monitoring the power supplies for the remote IAP platforms which extend the network. This work has included developing and supplying hardware solutions to integrate all these measurements for access over the Mesh wireless network. An example of a de-watering well solution is shown at top left.

With all measurements (approximately 1500 data elements in total, with equal number of calculated elements) integrated in a single database/interface monitoring of the project is much simpler and much more effective. The MLWeb® main page (shown at bottom left) shows monitoring locations throughout the property and status. If any alarms are generated the interface allows the operations personnel to quickly find the location and details of the alarm.