The Moonlight-Superior Copper Project, operated by US Copper Corp in California, is a dual-process facility producing copper, silver, and gold. The project combines heap leaching for oxide/transitional ore and conventional flotation for sulfide ore, targeting an average annual production of 120M lbs copper (concentrate) and 18M lbs copper (cathodes).
- Processing Routes: Heap leach (oxide/transitional ore) + Flotation concentrator (sulfide ore).
- Heap Leach: 2.98M tonnes/year capacity, 75% Cu recovery (oxide), 60% (transitional), producing Grade A cathodes via SX/EW.
- Concentrator: 54,348 tpd throughput, 88-90% Cu recovery, producing 23-28% Cu concentrate with silver/gold credits.
- Key Equipment: Gyratory crusher, SAG/ball mills (26,000 hp), Jameson cells, tower mill regrind, plate-and-frame filters.
- Tailings: Dual options – conventional pond or dry stack filtration (disk filters).
- Metals Production: 1.61B lbs Cu, 13.2M oz Ag, 78,660 oz Au over 14-year life (sulfide); 259.9M lbs Cu over 10 years (heap leach).
Source: US Copper Corp
Further Reading
- Project
- US Copper Corp Files PEA for Moonlight-Superior Project
- Major Mines & Projects | Moonlight-Superior Project
- Moonlight-Superior Project, California, US
- U.S. Copper Corp. releases new economic assessment
Technical report and processing history
The following archived source profiles have been consolidated here to preserve the project’s processing history and study context.
Moonlight-Superior Copper Project — 2025 Technical Report
Moonlight-Superior Copper Project — 2025 Technical Report
| Company | US Copper Corp |
| Date | 2025 |
| Commodities | Copper, Silver, Gold |
| Mine Type | Open Pit |
| Status | Development |
Executive Summary
The Moonlight-Superior Copper Project Preliminary Economic Assessment outlines a dual-process strategy designed to treat mixed oxide, transitional, and sulfide materials. The project utilizes acid heap leaching for approximately 22.36 million tonnes of oxide and transitional ore, targeting an average annual copper production of 9,000 tonnes over a 10-year leach period. This route is complemented by a conventional flotation concentrator designed to process 19.86 million tonnes of primary sulfide material annually, with an estimated mine life of 14 years.
The concentrator is designed for a throughput of 60,000 tons per day, producing a high-grade copper-silver concentrate with estimated recoveries of 88 to 90% for copper. Over the 14-year life, the concentrator is projected to produce 805,000 tonnes of copper, along with 13.2 million ounces of silver and 78,660 ounces of gold. The heap leach operation targets ultimate copper extractions of 75% for oxide material and 60% for transition material, utilizing a solvent extraction and electrowinning (SX/EW) circuit to produce Grade A cathodes.
The processing plant includes comprehensive unit operations such as primary gyratory crushing, semi-autogenous grinding (SAG) mills, ball mills, and multi-stage flotation circuits featuring Jameson cells for cleaner flotation. Tailings management includes options for drystack filtration or conventional pond disposal, with process water recycled from the tailings pond to minimize fresh water usage. The design balances capital expenditure and operating costs to optimize the project’s economic viability.
Website: https://uscoppercorp.com/project/
Report Date: 2025
Region:
Project Status: Development
Commodity: Copper, Silver, Gold
Throughput:
Mine Life:
Mine Type: Open Pit
Ore type:
Moonlight-Superior Copper Project — Technical Report
Moonlight-Superior Copper Project — Technical Report
| Company | Crown Mining Corp. |
| Date | TBD |
| Region | California, USA |
| Commodities | Copper, Silver |
| Mine Type | Open Pit |
| Throughput | 54,400 t/d |
| Status | Development |
Executive Summary
This Technical Report and Preliminary Economic Assessment outlines the design for the Moonlight-Superior Copper Project concentrator. The facility is designed to process a nominal 60,000 short tons per day (54,400 metric tons per day) of copper-silver mineralized material. The metallurgical processing procedures were developed based on test work by Continental and Allihies, aiming to produce a saleable high-grade copper concentrate with 28% copper content. Gold recovery is explicitly excluded from the process design.
The treatment plant consists of crushing and grinding circuits followed by a flotation process. The crushing circuit includes primary gyratory crushing, secondary cone crushing, and tertiary High Pressure Grinding Rolls (HPGR). The grinding circuit utilizes ball mills in closed circuit with hydro-cyclones. The flotation circuit comprises rougher, scavenger, and cleaner stages, including a regrind circuit to liberate fine copper grains. The final concentrate is thickened, filtered, and dispatched to smelters.
Process water will be recycled from the tailings pond, with fresh water reserved for gland service and reagent preparation. Final flotation tailings will be stored in a Tailings Management Facility (TMF). The plant operates on a 365-day schedule with two 12-hour shifts per day. Equipment availability is designed at 70% for primary crushing and 92% for downstream circuits to accommodate maintenance.
Reports
- entities/Moonlight_Superior_Copper_Project
Website: https://uscoppercorp.com/company/
Report Date: TBD
Region: California, USA
Project Status: Development
Commodity: Copper, Silver
Throughput: 54,400 t/d
Mine Life:
Mine Type: Open Pit
Ore type:
