Minera Tres Valles mining complex (MTV) is a Cu-Ag stratabound, manto-type deposit.

The MTV Project consists of two main deposit areas about 5km apart. The Don Gabriel area hosts the Don Gabriel Manto and Don Gabriel Vein deposits. The Papomono (“PPM”) area consists of seven known deposits: Massivo, Cumbre, Mantos Connection, PPM South, Mantos North, PPM North, and Epithermal.

Papomono
The dominant sulphides in the deposit are in decreasing order: chalcocite-covelite (~85%), bornite (~6%), enargite (~5%) and chalcopyrite (~4%). It is important to mention that the bulk of the chalcocite at MTV is hypogene. Very few parts were observed with supergene chalcocite. In places where intense fracturing and faulting occurs, the action of oxidizing agents generates oxide copper minerals: chrysocolla, malachite, brochantite and atacamite. For this reason, the traditional vertical zonation of oxides on top and sulphides in deeper parts are not identified in Papomono and the main oxide zones are related to more fractured zones, sometimes deeper than preserved sulphides.

The most common deposit geometry is the manto-type (stratiform). The individual “mantos” have a thickness that ranges from 2 to 50m, up to 500m strike extension and length along dip reaching 600m. Examples of this type of deposit geometry are the PPM South, Mantos Connection, and the Mantos North deposit. The other common geometry is vein-type, with a thickness between 2 and 15m ........

Overview
The open pit mine plan for the Don Gabriel Manto was developed by IMC staff in March 2018, and the underground mine plan for the Papomono Masivo inclined block cave and front cave were developed by Wood staff in July 2018. The integrated plan for the open pit and underground operations (integrated case), supporting the mine plan, was prepared by Wood staff in August 2018.

Slope Angles
The slope angle design for the Don Gabriel pit is based on two reports by E-Mining. The first is “Informe Extendido – Estimación de Parámetros de Diseño y Análisis de Estabilidad Rajo Don Gabriel” dated May 2011, and the second is an addendum dated April 2012. The two reports specified the same geotechnical design. The interramp slope angle was specified by E-Mining as 52º. The height of continuous slope could not exceed 150 m without the inclusion of an additional 20 m catch berm. This would limit the overall angle to about 50º. The E-Mining analyses looked at possible largescale slope failures (low probability) and bench scale failures. The bench scale issues, maintenance of catch berms and retention of most failures on the catch berms, were the main considerations for the interramp slope angle recommendations.

Mining Phases
The Don Gabriel phase designs are based on analysis performed by Tetra Tech and summarized in the PowerPoint presentation “Optimización y Diseño – Rajo Don Gabriel Minera Tres Valles”, dated December 22, 2017 ........

- subscription is required.

Minera Tres Valles mining complex (MTV) produces high-grade copper cathodes using a heap-leach and SX/EW process.

The crushed material is agglomerated, and water and acid are added to commence the leaching process. The agglomerated material is trucked to the heap leach area and stacked by front-end loaders. A grid of hoses with drippers is placed over the heaped material and the first phase of intensive leaching to recover the oxide mineralization during the first three-month period commences using constant and high acidconcentration irrigation. The product of this first leaching stage is the “oxide-pregnant leach solution” (oxide-PLS), which has a high copper content and is accumulated in a pond at the bottom of the leach pads. For the subsequent six months, the material is irrigated on an intermittent basis, with lower acid concentration to extract the copper from sulphides (chalcocite, covellite and some bornite). The resulting PLS (sulphidePLS) is stored in anoth ........