About
Pinto Valley has been in operation since 1972 and has produced more than four billion pounds of copper since then. Capstone acquired it from BHP in October 2013. The operation consists of an open-pit mine, a 60,000 tonnes per day (“tpd”) concentrator plant and a 25,000 tpd SX-EW plant. Pinto Valley is currently the only operating mill and the second-largest employer in the Globe-Miami district, supporting ~2,250 direct and secondary jobs each year.
The mine uses conventional open-pit hard rock mining methods (drilling, blasting, loading and hauling) to move copper-bearing sulphide ore to the primary crusher. The processing plant is a conventional porphyry copper concentrator that produces a primary copper sulphide concentrate and a by-product molybdenum concentrate. The plant flowsheet is typical of its era with primary through tertiary crushing, ball milling and conventional flotation. The mill has undergone several optimizations during its life. The most recent upgrade, the $31 million PV3 Optimization, was completed in 2021 and focused on innovation and a series of low-capital, quick payback projects to debottleneck operational performance. This included investments in the fine crushing plant and two new ball mill shells, as well as upgrades to the tailings thickeners and tailings pumping stations. The project improved productivity and increased recoveries and mill throughput to approximately 60,000 tpd during peaks.
The mine received a new US Forest Service Mine Plan of Operations in November 2021 and is fully permitted to operate for the duration of the current life of mine plan, which extends to 2039.
