Design Day team automates copper leaching

A University of Arizona capstone team is working to improve copper mining with a process familiar to many. Interdisciplinary Capstone Team 26017 worked with Freeport-McMoRan to create an automated leaching system for more efficient and sustainable mining.

“Our main objective was to develop a piece of lab equipment that automates a hydrometallurgical system,” said Everett Cota, systems engineering student and team lead. “Freeport wanted us to track flow rates, moisture and temperature while solution runs through ore samples... The best way to visualize it is like drip coffee. You have a little bit of liquid dripping slowly through the material over time.”

Leaching uses a chemical solution to dissolve copper from crushed rock. In laboratory testing, technicians pack ore into vertical columns and slowly drip solution through them, resulting in a copper-containing liquid.

These column tests can run for months – sometimes up to 180 days – and traditionally require individual pumps for each column to deliver precise amounts of solution. Maintaining those pumps demands frequent calibration and hands-on monitoring.

“We thought, what if we try a gravity-fed system?” Cota said. “We could eliminate their biggest problem and replace it with a sensor and a valve to control the flow.”

The design uses a reservoir positioned above the column so gravity pulls the solution through. A flow meter measures the exact amount of liquid delivered, while a small pinch valve opens and closes in short bursts to regulate the daily dosage.

“It doesn’t change much for them operationally,” Cota said. “But it removes the constant calibration and maintenance of pumps.”

The system also has the potential to scale across large testing facilities. Some research labs run hundreds of column systems simultaneously, meaning a simplified setup could significantly cut costs and labor.

Watch interdisciplinary capstone teams showcase their work at the Craig M. Berge Design Day on May 4.