| Company | M3 |
| Date | 2026 |
| Region | Arizona, USA |
| Commodities | Copper |
Executive Summary
The Johnson Camp Mine (JCM) is a conventional open pit, heap leach operation utilizing solvent extraction and electrowinning (SX-EW) to produce Grade A copper cathodes. The facility includes a permanent heap leach pad, solution ponds, the SX circuit, a Tank Farm, and the EW Tankhouse. The report details the design basis for a single SX-EW facility capable of producing 25 million lbs of cathode copper per annum with 90% availability.
A significant development highlighted in this report is the construction of Pad 5, completed in 2025. This new leach pad area is designed to handle Run-of-Mine (ROM) oxide and transition materials initially, with capacity for 44 million tons of leachable material. The pad utilizes gravity drainage to a combined ILS-PLS pond, which pumps solutions back to the existing plant. The design includes comprehensive containment systems, including soil liners, HDPE geomembranes, and emergency runoff ponds.
The report also introduces the Nuton Demonstration, an industrial-scale engineered sulfide heap leach operation using Nuton’s proprietary bioleaching technology. This process uses elevated temperature biological leaching with naturally occurring bacteria to accelerate recovery from primary sulfides. The demonstration involves crushing, agglomerating, and stacking sulfide material for three years of mining and five years of leaching to test efficacy and refine recovery kinetics.
Reports
Website: https://www.gunnisoncopper.com/news/news-2021/excelsior-mining-awards-m3-engineering-of-arizona-the-contract-for-gunnison-and-johnson-camp-technical-report-update
Report Date: 2026
Region: Arizona, USA
Project Status:
Commodity: Copper
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