The El Castillo Complex includes two operating mines, El Castillo and San Agustin.

El Castillo
Deposit Type
El Castillo is interpreted to be a porphyry-style gold system related to Eocene granodiorite– diorite porphyries that intrude Cretaceous clastic and carbonate sediments in an extensional tectonic setting. Gold mineralization occurs throughout the magmatic-hydrothermal system in space and time and is related to sulphide mineralization spatially associated with early potassic development and genetically related to an overprint of phyllic alteration. Supergene alteration, formed as a product of acid leaching, has resulted in argillic-quartz alteration assemblages within the oxide zone of the deposit. The main gold event is believed to be associated with magmatic hydrothermal fluids corresponding to phyllic alteration.

The El Castillo gold system is similar to that found at Andacollo, Chile (Reyes, 1991 and Oyarzun, et al., 1996). Andacollo is a Cretaceous diorite to granodiorite porphyry copper-gold system with central porphyry copper-gold mineralization related to a classic porphyry alteration assemblage and a distal sediment-hosted (manto) low sulphidation and epithermal-level gold satellite system. Fluid inclusion work by Oyarzun et al. (1996) indicates that the manto epithermal gold deposits may in fact be related to another intrusive that has not been recognized at the surface due to high temperature fluid inclusions (about 365ºC) that ........

The El Castillo Complex includes two operating mines, El Castillo and San Agustin. Temporarily pausing mining activities mine San Agustin by Q4 2023. Suspended mining activities at El Castillo in 2022 ahead of schedule. El Castillo El Castillo is an Owner-operated mine using conventional equipment and conventional mining methods. The El Castillo mine is a relatively low-grade gold deposit that benefits from a low strip ratio and disseminated mineralization that is amenable to bulk mining activities and good heap leach recoveries. The operation is situated in a semi-arid environment surrounded by moderate topography. There are three mine phases remaining in the LOM plan: • The Phase 10.2 design is approximately 300 m long by 100 m wide with 36 m depth. Total Mineral Reserves contained in this phase are 1.1 Mt at an average grade of 0.25 g/t Au with a strip ratio of 0.21; • The Phase LB design is approximately 700 m long by 250 m wide with 170 m depth. Phase LB contains 3.8 Mt of Mineral Reserves grading 0.27 g/t Au and a strip ratio of 1.39; • The Phase WP design is approximately 700 m long by 400 m wide with 150 m remaining depth. Phase WP contains 6.6 Mt of Mineral Reserves grading 0.44 g/t Au with a strip ratio of 0.61. The mining method consists of traditional drill-and-blast operations followed by excavator loading of rigid-body haul trucks for ore transport to the crusher and waste transportation to designated WRSF locations. Pit Design Pit designs include a ramp ........

San Agustin
Crushing and Conveying
The Plant 1 crushing circuit includes a primary jaw crusher followed by secondary crushing with two cone crushers operated in open circuit to produce a final crush size of P80 22 mm. A hopper in front of the primary crusher is fed directly by haul trucks, or by a front-end loader from stockpile. From the dump hopper, ore is fed across a vibrating grizzly with oversize being directed to the jaw crusher and the undersize directed to the primary crushed ore stockpile.

The primary crushed ore is reclaimed from the primary stockpile and conveyed to two doubledeck vibratory screens. Screen oversize is combined and conveyed to a surge bin, which feeds two secondary cone crushers. The secondary crushing circuit operates in open circuit with the crushed product combined with the undersize material from the vibrating screens and directed to the crushed ore stockpile. Plant 1 produces approximately 17,000 t/d of P80 22 mm crushed ore product.

The Plant 2 crushing circuit is nearly identical to the Plant 1 crushing circuit, except the equipment is slightly smaller and the secondary circuit uses one only one vibrating screen and cone crusher rather than two. Plant 2 produces 13,000 t/d of P80 22 mm product.

The two streams of crushed product join at a common crushed product stockpile. Ore from the crushed product stockpile is conveyed 0.5 km to the heap leach pad on two overland conveyors and then onto the heap leach pad with a system of 24 grasshopper field conveyors and stacked at 30,000 t/d in 8 m high lifts with an index conveyor and mobile radial stacker.

The ore is belt-agglomerated with 2 kg/t to 3 kg/t cement (2019 excluded) and 5.6 kg/t lime as required for improved percolation. Since April 2021 an agglomeration polymer (DustTreat) has been used in place of cement at an addition rate of 0.05 kg/t.

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