The Tres Valles mining project is based off of two mines: Papomono (an underground mine)
and Don Gabriel (an open pit mine), both of which are located in the Manquehua gorge in the Chalinga valley.
Its processing plant has a normal capacity of 5,400 tonnes per day (tpd) of ore, and consists of a copper
leaching operation that has a crushing and agglomeration plant, heap leach pads and pools, and an SX-EW plant.
The facility is designed to produce up to 18,500 tonnes per annum (tpa) of thin copper cathodes.
Minera Tres Valles is owned by two prominent partners, Sprott Resource Holdings (70%) and the Vecchiola Group (30%). These two businesses complement one another by both promoting the development of the project in an efficient and sustainable manner with high operational standards.
The Papomono ore body is composed of the Cumbres, Papomono (underground) and Norte mines. It is located in the Cárcamo and Chalinga (Manquehua) valleys. In the last valley mentioned, the Don Gabriel open-pit mine is also found.
The ore processing plant is in the Chuchiñí Valley in Quilmenco, which is located at a distance of 12 kilometers from the mines. The operations that exist in these three valleys give way to the name Minera Tres Valles.
Exploration campaigns at Minera Tres Valles started in 2005 with prospecting at the Papomono deposit. Subsequently, prospecting and exploration developed at Don Gabriel, leading to the formation of the Environmental Impact Study that was submitted to Chile’s Environmental Evaluation Service (SEA) in 2009. It was approved during that same year, and it includes the master plan of the operation.
Construction began in 2009, and continued throughout 2010, before starting operations in 2011. VALE was the only entity to own the Tres Valles project until 2013, which was when the Vecchiola group became the sole proprietor. Just 4 years later, in 2017, 70% of the company was acquired by Sprott Resource Holdings.
Sprott is a Canadian Company dedicated to investing in projects that are related to natural resources throughout the world.
Minera Tres Valles’ process starts by receiving ore from both of the company’s own mines as well as third parties at the main Ore Stockyard. The different batches are loaded into a primary jaw crusher that reduces the rock to fragments smaller than < 90 mm. From this stage, the ore is sent to a standard cone type secondary crusher, which produces fragments no bigger than < 25 mm (1”).
This material is sent to the tertiary crusher, where the grain size is < 14 mm (or ⅜”). Finally, the ore is sent to the quaternary crusher, which reduces the size of the stacking ore to < 6 mm (or ¼”). The crushed ore then goes into the Agglomerate Drum, where water and acid are added to the ore in order to start the sulfate creation process and stick the finer particles to the coarser ones.
The agglomerated ore is then sent by truck to the heap leach area where it is stacked by Front-End-Loaders. A grid of hoses and drippers is placed over the stacked modules and its purpose is to leach the oxide ore during a 3-month period. The product of the leaching process is called “pregnant leach solution” (PLS), which is accumulated in big ponds at the bottom of the leach pads.
The PLS is pumped into the “solvent extraction” plant (SX) where organic resins are used to capture the copper ions in the solution over several stages. In the last stage, the highly concentrated solution is called Electrolyte.
This solution is sent to the “electrowinning” plant (EW) where the process of electrolysis is responsible for the deposition of metallic copper over steel blades. The blades are then sent to the stripping machine, where pure copper blades (cathodes) are separated from the steel blades. The cathodes are then tied up in bales and are ready to be commercialized.