Deposit Type
The Agua Rica deposit is interpreted as a substantial gold-rich porphyry copper-molybdenite deposit, formed by multistage porphyry intrusions of Miocene age. These porphyries, interpreted as intrusions distal to the Miocene Farallón Negro Volcanic Complex, are of calc-alkaline dacitic composition and result from arc magmatism produced by subduction below the continental western margin of South America. The principal volcanic centre hosts the giant Bajo de la Alumbrera porphyry Cu-Au-Mo deposit, now operating as MAA, 35 km to the west.

The emplacement of these intrusions produced porphyry-style veining (stockwork, A and B veins), vein and disseminated mineralization (chalcopyrite, molybdenite, pyrite, pyrrhotite, magnetite and bornite), and alteration (potassic and propylitic).

Continued hydrothermal activity produced various phases of hydrothermal breccias, accompanied by phyllic alteration, intense advanced argillic alteration (pyrophyllite and alunite), and the formation of a high sulphidation epithermal overprint (pyrite-covellite-enargite-galena-sphalerite, containing Cu-Au-AgPb-Zn). This later epithermal mineralization partially replaced the earlier porphyry-style mineralization. A gradual unroofing of the magmatic and hydrothermal system is proposed to explain this juxtaposition of mineralizing environments that usually occur at very different depths.

A stage of supergene alteration, typical of porphyry copper environm ........

Agua Rica Mineral Reserves are contained within a single open pit. The pit is located in a valley, Quebrada Minas, flanked by mountainous terrain ranging in elevation between approximately 3,000 masl to 4,000 masl.

The Agua Rica deposit will be mined via a conventional high tonnage, truck and shovel open pit operation with ore being crushed at the new mine site and conveyed approximately 35 km west to the existing Alumbrera processing plant. The average LOM material moved is expected to be approximately 108 Mtpa, with an ore feed of 40 Mtpa and average LOM strip ratio of 1.66. Mine waste will be deposited in the Choya valley, adjacent to the Agua Rica, at WRF.

The mining strategy includes the use of a mining contractor to develop the first two stages with the objective of minimizing the Project’s initial capital cost, while the production stage will be carried out primarily by the Parties.

Due to the mountainous topography, the Agua Rica mine will require mine pioneering activities such as roads, dykes, and crushing pad to properly enable the mine commencing.

Prestripping of 83.8 Mt of overburden will be required. Prestripping is forecast to take place over a 24 month period after all required mine pioneering is completed.

A maximum of 165 Mtpa (108 Mtpa average) is planned to be mined from the Agua Rica deposit. A total of 40 Mtpa of plant feed is planned for the mine, with a ramp-up of 28 Mt for the first year. The aver ........

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The Alumbrera process plant and supporting facilities were in continuous operation since its initial start up in 1997 until the open pit Mineral Reserves were depleted in 2017. The Alumbrera operation was shut down in October 2018 and placed on care and maintenance pending closure. The Alumbrera mine and concentrator processed a nominal 90,000 tpd of copper and molybdenum ore.

The Project is focussed on maintaining as much of the Alumbrera process and supporting infrastructure as possible. The Agua Rica ore will be crushed at the new mine site and conveyed 35 km west to the existing Alumbrera mill feed stockpile. Nominal LOM for the Project is 28 years. The Alumbrera concentrator capacity will be increased from the current 90,000 tpd to a nominal throughput of 110,000 tpd (40 Mtpa).

The metallurgical plant and main production facilities include the following:
• Primary crushing, conveying, and stockpiling of ore
• Grinding
• Bulk Cu-Mo flotation and ........