The Cerro del Gallo copper-gold-silver deposit can be considered to be a member of a distinct subclass of “reduced” porphyry-style copper-gold mineralization as first proposed by Rowins (2000c). These reduced porphyry copper-gold deposits lack primary hematite, magnetite and sulfate minerals, but contain abundant hypogene pyrrhotite, commonly have carbonic ore fluids, and are associated with ilmenite-bearing, reduced I-type granitoids (Rowins 2000c). Cerro del Gallo displays all these features. In addition, there is a consistent pattern of higher temperature potassic alteration overprinted by lower temperature propylitic-style mineral alteration. Propylitic alteration boundaries are gradational and irregular, and more widespread than potassic alteration.

The Cerro del Gallo copper-gold-silver deposit also has characteristics supporting an intrusion related gold system (IRGS) model as proposed by Thompson et al 1999; Rowins 2000c; Champion 2005; Hart 2005. IRGS deposits are typically found in continental tectonic settings inboard of convergent plate boundaries, often where the regional metallogeny is characterized by tungsten-tin magmatic provinces. Felsic intrusives have an intermediate oxidation state between ilmenite and magnetite series with a gold-enriched metal assemblage derived from igneous fractionation, and a distinctive metallogenic signature of gold, bismuth, tin and tungsten. Hydrothermal fluids are carbonic, and pyrrhotite is common.

The C ........

The Cerro del Gallo project has been planned as an open-pit truck and shovel operation. The truck and shovel method provides reasonable cost benefits and selectivity for this type of deposit. Only open-pit mining methods are considered for mining at Cerro del Gallo.
The open pit mining operation will require the stripping and disposal of waste rock. The total waste quantity is approximately 57.8 million tonnes with an overall mining waste-to-ore ratio of approximately 0.63:1. The bulk of the waste rock from the pit will be placed into a single external waste dump located to the east of the pit and north of the HLF and is named as the Waste Rock Dump (WRD).

For the PFS and based on the waste rock quantities and maximum footprint area provided by others, Golder developed a WRD design in its 2019 Study. Due to the potential for acid waste rock drainage three geomembrane lined contact water ponds are designed at the base of the three natural drainages within the area of the WRD.

The initial waste that is extracted from the pit will be placed below the Phase 1 and 4 leach pad footprints as structural fill and select waste rock, thereafter the waste will be placed in the western drainage of the WRD. After the western drainage of the WRD is full to capacity, the WRD surface will be regraded to an overall slope of 3H:1V that will cover the contact water pond and the surface will receive a cover system. The same process will be conducted for the remaining t ........

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