Mineral Processing Circuit

The Minera Tres Valles Copper Project, located in the Coquimbo Region of Chile, is currently operating using a heap-leach and solvent extraction-electrowinning (SX-EW) process to produce high-grade copper cathodes. The ore is sourced from open pits including Don Gabriel, Papomono, and Cumbre. The current process involves crushing the ore to a target size of 80% < 6.4mm, followed by agglomeration with water and sulfuric acid. The material is then stacked on leach pads where oxide ore is leached first, followed by sulphide ore extraction.

The La Libertad processing plant is a conventional facility designed to treat approximately 2.25 million tonnes per annum (Mtpa) of ore. The plant utilizes a circuit comprising comminution, agitated cyanide leaching, and carbon adsorption, followed by carbon elution, electrowinning, and doré production. Current gold recoveries are reported to be between 92% and 95%. The plant processes a blend of ore from open pit and underground mines, as well as reclaimed material from historical heap leach operations, which currently constitutes approximately two-thirds of the feed.

The Banio Potash Project Preliminary Economic Assessment (PEA) outlines a solution mining approach for extracting potash-rich brines from the wellfield, favoring this over conventional underground mining. The proposed processing regime targets the production of Muriate of Potash (MOP) at three capacity scenarios: 400 kt/a, 600 kt/a, and 800 kt/a, primarily as granular solids with a K60 grade (95% KCl purity). The process is designed to maximize resource recovery, producing a high-grade vacuum salt by-product alongside the potash.

P&E’s report for Queenston Mining, effective February 16, 2012, assumes 90% copper recovery to a saleable concentrate, based on testwork and historical milling of the deposit.

This section outlines the recovery methods for the Blue River Tantalum–Niobium Project based on a Preliminary Economic Assessment (PEA) effective September 29, 2011. The process plant is designed for a nominal capacity of 7,500 tonnes per day, handling Run-of-Mine (ROM) material from underground operations. The flowsheet utilizes conventional technology to crush, grind, and separate tantalum and niobium minerals via flotation, followed by refining processes to produce high-purity chlorides and oxides.

This Pre-Feasibility Study (PEA) for the West Cache Gold Property outlines metallurgical testwork and processing options for gold recovery. Based on recent testwork, two primary flowsheets were evaluated: a dedicated gravity-float-leach option and toll processing at existing regional facilities. The preferred flowsheet involves gravity concentration of free gold using centrifuges and tabling, followed by flotation of a gold-sulphide concentrate and cyanidation of the reground float concentrate. This option achieved combined recoveries averaging 97% and produces cyanide-free flotation tailings suitable for mine backfill.

The Gemfield Project Technical Report outlines a comprehensive recovery method designed to produce doré bars containing gold and silver. The process flowsheet includes three-stage crushing and screening to produce leach feed, followed by heap leaching using sodium cyanide solution. The pregnant solution is processed through a carbon adsorption plant, followed by stripping, regeneration, electrowinning, and smelting to produce doré bars for shipment to third-party refiners.