The Filo del Sol project is an epithermal copper-gold-silver open-pit being developed in the Atacama region of Chile. Image courtesy of Filo Mining Corp.
The Filo del Sol copper-gold-silver project is expected to produce 60,000t per day of ore. Image courtesy of Alchemist-hp.
Pre-feasibility study for the Filo del Sol project was completed in January 2019. Image courtesy of Filo Mining Corp.

Filo del Sol Project is a high-grade epithermal copper-gold-silver open-pit project being developed in South America. Filo Mining is developing the project, which is located in the Atacama Region of Northern Chile and the nearby San Juan province of Argentina.

Filo Mining holds the mineral titles in Argentina through its subsidiary Filo del Sol Exploración, while Frontera Chile Limitada holds the titles in Chile.

Pre-feasibility study (PFS) of the project was completed in January 2019. Estimated to require an initial capex of $1.27bn, the project will produce London Metal Exchange (LME)-grade copper cathodes through its anticipated mine life of 14 years.

Filo del Sol project location, geology, and mineralisation

Located approximately 140km from Copiapo, Chile, the Filo del Sol project is made up of mineral titles held in both Chile and Argentina.

The project hosts both porphyry copper-gold and high-sulphidation epithermal copper-gold-silver mineralisation. The mineralised system comprises Middle Miocene porphyry intrusions and high-sulphidation epithermal alteration within PermoTriassic rhyolite basement rocks.

The project is made up of two contiguous zones of mineralisation namely Filo del Sol and Tamberias (previously called Flamenco or Filo Mining South).

Filo del Sol project reserves

The probable ore reserves of Filo del Sol Project are estimated to be 259.1Mt, grading 0.38% copper, 0.33g/t gold, and 0.33g/t silver. The project is estimated to contain 2,226 million pounds (Mlbs) of copper, 2.77Moz of gold, and 126Moz of silver.

Mining and processing at the Filo del Sol project

The copper-gold-silver project is proposed to be extracted by using conventional open-pit mining methods involving drilling and blasting followed by hydraulic shovels and front-end loaders. It is expected to produce 60,000 tons per day of ore, at a mining rate of 65 metric tons (Mt) a year.

The mined ore will be initially forwarded to the primary crusher, followed by a closed-circuit secondary crushing system. The ore will then be processed at a heap leach pad where copper will be leached with acid. The recovered leach solution will undergo solvent extraction and electro-winning processes to produce LME-grade copper cathodes.

Ore will be rinsed, neutralised, and removed from the leach pad, following the leaching process of copper. The material will then be agglomerated and stacked on a heap leach pad for leaching gold and silver in a cyanide solution.

Merrill-Crowe zinc precipitation process will be used to recover gold and silver from the resulting pregnant leach solution. It will be further smelted to produce doré.

The final copper cathode will be transported by truck to Puerto Caldera for shipment to customers, while doré will be transported to Aeropuerto Desierto de Atacama for export by air.

Infrastructure facilities

The project is accessible by road from Copiapó, Chile through the C-35 sealed road along the towns of Tierra Amarilla and Punta del Cobre. It can also be reached through San Juan, Argentina, by National Route 40 (NR40) along the towns of San Jose de Jachal and Guandacol.

Filo Mining proposes to source power for the Filo del Sol project through a 127km-long, 110kV single-circuit transmission line from Los Loros substation in Chile.

Water required for the project operations will be collected from aquifers in Argentina.

Contractors involved

Ausenco Engineering Canada prepared the Filo del Sol project’s PFS, with support from consultants such as AGP Mining Consultants, Knight Piesold, and SRK Consulting, Advantage Geoservices, Merlin Geosciences, and BGC Engineering.