Santa Cruz Copper Project: Heap Leach & SX/EW Processing Circuit Overview

Santa Cruz Copper Project — 2025 Feasibility Study & Technical Report

Executive Summary

The Santa Cruz Copper Project, located in Arizona, is the subject of a 2025 NI 43-101 Feasibility Study & Technical Report prepared by Ivanhoe Electric. The project involves the development of an underground mine designed to extract oxide and secondary sulphide ores for processing into LME Grade A copper cathode. The facility is planned to operate for approximately 24 years with a design daily stacking rate of 22,000 tonnes.

The processing plant utilizes a conventional heap leach and solvent extraction/electrowinning (SX/EW) flowsheet. Ore is crushed to sub-9.5 mm, agglomerated with sulphuric acid and sodium chloride, and stacked on an on/off pad for leaching. The resulting pregnant leach solution is processed through two parallel SX trains and recovered via an EW circuit with 124 cells. The design targets a life-of-mine total copper recovery of 92.2%.

Operational parameters indicate a life-of-mine ore production of 136 Mt with a design annual copper production of 76,000 tonnes. The project includes comprehensive solution management with lined ponds and a zero-discharge plan. Spent ore will be managed in dedicated piles, with approximately 50% processed for paste backfill. The process is designed to run 24 hours per day, 365 days per year.

Website: https://ivanhoeelectric.com/electric-metals/santa-cruz/

Report Date: 2025-06

Region: Arizona, USA

Project Status: Development

Commodity: Copper

Throughput: 22,000 tpd

Mine Life: 24 years

Mine Type: Underground

Ore type:

Santa Cruz Copper Project — 2025 Technical Report

Executive Summary

The Santa Cruz Copper Project is a feasibility study for an underground mining operation located in Arizona, designed to process oxide and secondary sulphide ores. The proposed processing facility utilizes a heap leach circuit followed by solvent extraction and electrowinning (SX/EW) to produce LME Grade A copper cathode. The design is based on conventional technologies and proven equipment, with a life-of-mine ore production of 136 Mt.

Operations are planned to run 24 hours per day, 365 days per year for approximately 24 years. The design daily stacking rate is up to 22,000 tonnes, with an overall copper recovery target of 92.2%. The process includes primary, secondary, and tertiary crushing, agglomeration with sulphuric acid and sodium chloride, and an on/off heap leach pad configuration.

Spent ore management involves paste backfill for approximately 50% of the material, with the remainder stored in dedicated piles. The facility includes seven leach cells, solvent extraction trains, and an electrowinning tankhouse. Water management is designed as zero-discharge, utilizing lined ponds and recycling systems to minimize environmental impact.

Website: https://ivanhoeelectric.com/electric-metals/santa-cruz/

Report Date: 2025

Region: Arizona, USA

Project Status: Development

Commodity: Copper

Throughput: 22,000 tpd

Mine Life: 24 years

Mine Type: Underground

Ore type:

Santa Cruz Project — 2023 Technical Report

Executive Summary

This NI 43-101 Technical Report details the recovery methods and processing plant design for the Santa Cruz Project. The facility is designed to process 15,000 dry metric tonnes per day (t/d) at 94% utilization, with an operating range of 10,800 to 16,300 t/d. The mine is classified as an underground operation with a planned mine life of 20 years. The project is currently in the development phase, with equipment sizing based on ultimate plant production targets.

The processing flowsheet is a hybrid system designed to handle four distinct ore domains: Exotic, Oxide, Chalcocite, and Primary Sulfide. The plant utilizes a combination of whole ore agitated leaching for acid-soluble copper and conventional flotation for sulfide minerals. Comminution involves primary crushing, SAG and ball milling, and tertiary grinding using vertical stirred mills. The leach circuit includes five agitated tanks followed by counter-current decantation (CCD) thickeners.

Production targets include an annual copper cathode production of 32,000 to 61,400 tonnes and copper concentrate production of 14,000 to 35,100 tonnes. The plant incorporates Solvent Extraction and Electrowinning (SX-EW) for cathode production, achieving a combined copper recovery of 95.4%. Reagents include sulfuric acid, limestone, lime, and flotation collectors, with tailings managed in a storage facility and partially used for paste backfill in the underground mine.

Website: https://ivanhoeelectric.com/electric-metals/santa-cruz/

Report Date: September 2023

Region: Unknown

Project Status: Development

Commodity: Copper

Throughput: 15,000 t/d

Mine Life: 20 years

Mine Type: Underground

Ore type:

Santa Cruz Copper Project — 2025 Feasibility Study

Company: Not explicitly stated, but associated with Ivanhoe Electric.
Date: June 2025
Region: Arizona
Commodities: Copper

Executive Summary

The Santa Cruz Copper Project in Arizona is proposing an on/off heap leach process to recover copper from oxide and secondary sulphide ores. The pregnant leach solution (PLS) generated from the heap leach will be processed through an on-site solvent extraction (SX) and electrowinning (EW) circuit to produce LME Grade A copper cathode. The process design leverages established technologies and is based on extensive metallurgical testwork conducted on the project’s mineralized material.

The mine is planned for a life of approximately 24 years with a daily stacking rate of up to 22,000 tonnes. The processing facility includes crushing, agglomeration, heap leaching, SX, EW, and associated reagent preparation and water treatment. Key operational parameters include a heap leach feed particle size of sub-9.5 mm, an irrigation rate of 8 L/h/m², and an overall copper recovery of 92.2%. The mine is projected to produce 76,000 tonnes of copper annually.

Website: https://ivanhoeelectric.com/electric-metals/santa-cruz/

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