Deposit Types
The Marimaca deposit appears to be a new deposit style and does not readily conform to any of the major published geological models.

The deposit occurs in a district that has a number of vein-style IOCG deposits, which have common features including regional metamorphism/metasomatism, Ca–Na alteration, the presence of magnetite and hematite, chalcopyrite as the major copper-bearing mineral, and an overall low sulphide content (Sillitoe, 2003; Richards and Mumin, 2013). The Marimaca deposit setting includes some of these elements.

However, Marimaca also has affinities with “manto-type” mineralization styles, although the monzodiorite mineralization host is unusual, since the known manto-type deposits are typically associated with volcanic piles. If the host rock issue is not taken into consideration, Marimaca is analogous to manto-type copper deposits such as Mantos Blancos (Chavez, 1983) or El Soldado (Boric et al., 2002). The critical role of structures, dykes, and alteration zoning is a common feature in these deposits. The deep and extensive development of supergene alteration and oxidation is similar to that seen at Mantos Blancos.

The sulphide and alteration mineralogy at Marimaca resemble those encountered within IOCG systems; however, the lack of iron oxides and gold and the occurrence of hypogene chalcocite and covellite are not common in IOCG deposits (Richards and Mumin, 2013). These features appear to be more ........

Open pit mining is contemplated, using equipment conventional to the industry.

The open pit area was divided into three geotechnical zones, with pit slope angles that range from 42–52º. Mining dilution, based on a cut-off grade of 0.2% CuT is assumed to be 2.3% for tonnes, and a contained copper loss of 4.6% will result.

Eight pit phases are planned. phase 1 targets the material with the highest grade in the central area, down to 920 masl. phases 2 and 3 are successive expansion to the north, down to 960 masl and 870 masl, respectively. phase 4 is an almost independent pit at the northern area of the deposit with an exit to the north and a connection with phase 3 for exiting to the primary crusher to the south. This phase will extend to the 890 masl. phase 5 is an expansion to the west of the main pit, to 830 masl. phases 6 and 7 are final expansions to the south and west, respectively to 890 masl and 830 masl. phase 8 corresponds to the final expansion of the north pit, to 880 masl.

A road width of 30 m was selected to accommodate trucks up to 190 t. NCL used a 10% road gradient which is common in the industry for this type of truck. The 2020 PEA mine plan is designed with 10 m benches stacked to 20 m (i.e. double benching) for the geotechnical Zone 1 (East wall). Mining costs are based on blasting 10 m benches for every material type. Additional 20 m wide safety berms were included in the design when the slope height exceeds 150 m, in acc ........

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