This feasibility study presents a proposed gold recovery operation using heap leaching and an adsorption-desorption-recovery (ADR) plant, based on extensive metallurgical testwork and historical data for the Fenix Gold Project in Chile's Atacama Region.
Report context
This technical report is a NI 43-101 Feasibility Study for the Fenix Gold Project, located in the Atacama Region, III Region, Chile. The report was prepared for Rio2 Limited with an effective date of October 16, 2023. The document incorporates mineral processing and metallurgical testing, recovery methods, and process design parameters for the proposed project.
Processing route
Process Flow Diagram Development
The process design basis was developed using metallurgical testwork data from multiple campaigns conducted between 2008 and 2021. The proposed processing route consists of a conventional heap leach operation with an ADR plant for gold recovery.
Lime Plant
The proposed design includes a lime plant for the preparation and delivery of lime slurry to the crushing and agglomeration circuit. Lime is added to maintain pH conditions favourable for gold dissolution during heap leaching.
Heap Leaching
The proposed heap leaching operation involves stacking crushed and agglomerated ore on a leach pad. The report states that metallurgical testwork included column leach tests conducted from 2010 to 2021 to evaluate gold extraction performance under various conditions. Historical testwork by Kappes Cassiday Associates (KCA) in 2010, 2013, 2014, and 2017, as well as pilot scale testing in 2020, informed the design parameters. The relationship between gold head grade and extraction, the effect of particle size on gold extraction, and cyanide and lime consumption were all examined in the testwork.
ADR Plant
The proposed ADR (Adsorption-Desorption-Recovery) plant is designed to recover dissolved gold from pregnant leach solution. The plant includes carbon adsorption columns, a desorption circuit, and gold recovery by electrowinning and refining.
Gold Recovery
Gold recovery estimates in the feasibility study are based on the column leach testwork results. The report presents a gold production schedule that shows the proposed mine production schedule and expected recovery performance.
Water Management
Process water consumption was estimated based on the proposed heap leach operation and ADR plant requirements. The water management system is designed to recycle process solutions and manage solution inventories on the leach pad.
Key reported parameters
| Parameter | Value | Basis |
|---|---|---|
| Processing method | Heap leaching + ADR plant | Proposed design |
| Gold extraction | Variable by head grade and particle size | Column leach testwork (2010-2021) |
| Cyanide consumption | Testwork dependent | Historical column tests (KCA 2010-2017, pilot 2020) |
| Lime consumption | Testwork dependent | Historical column tests |
| Copper impact on extraction | Evaluated in testwork | Metallurgical studies |
| Particle size effect on extraction | Evaluated in testwork | Column leach tests |
| Water source testing | Multiple water sources tested | Gold extraction tests with different water sources |
Project website: https://www.rio2.com/fenixgold
Technical qualifications
This feasibility study is based on metallurgical testwork performed by AMTEL (2008), Kappes Cassiday Associates (2010, 2013, 2014, 2017), Plenge (2011), and pilot scale testing (2020). The report states that gold extraction results are dependent on head grade, particle size, and copper content. The proposed design parameters have not been confirmed by full-scale operations. The report notes that column test results from 2010 to 2021 were summarised to support the process design basis. No operating data from the proposed plant exists as the project has not been constructed.
Source: NI 43-101 Technical Report on the Feasibility Study for the Fenix Gold Project, effective October 16, 2023, sections 1.10, 1.14, 13, and 17.
