The Marimaca project is located in the II Region of northern Chile, close to the coast and major infrastructure. It is ~ 1 hour’s drive north of the port of Antofagasta and 22km from the port of Mejillones. It is 14km from the Antofagasta to Tocopilla paved highway.
Coro has the right to acquire a 75% interest in the project by completing a resource estimate, engineering studies and arranging financing, (see Agreement Terms below). To date, Coro has completed a 16 hole reverse circulation (RC) drilling program for 2,680m, to test outcropping mineralization exposed at surface and in several artisanal miner’s open cuts.
Based on the work carried out to date, Coro believes that Marimaca has the potential to host a deposit containing greater than 50mt @ ~0.6%CuT. This potential tonnage and grade is conceptual in nature and there has been insufficient exploration to define a mineral resource. The Company will complete additional RC and diamond drilling aimed at completing an initial NI43-101 resource estimate later this year.
Marimaca is located in a belt of Mesozoic age copper deposits known as the Coastal Copper Belt, which range in (pre-mining) size from Mantos Blancos ~500mt to Ivan ~50mt. They occur in a variety of host rocks and have differing morphologies, but have a common Cu-Ag primary mineralogy zoned from bornite outwards to chalcopyrite and pyrite, deep oxidation and frequently, secondary enrichment.
The Marimaca property contains a number of NNE-SSW trending, ~60oE dipping, broad shear zones, cross cut by later NE-SW oriented sub vertical feeder structures, all hosted by Jurassic age intrusive rocks. The intersection of these structures has produced wide NW-SE oriented zones of eastward dipping mineralization that have been exploited from a series of open cuts and small underground workings by artisanal miners. Surface mapping and drilling has shown that the mineralization is comprised of multiple, thick, higher grade structures bordered by lower grade halos.
Half of the RC holes bottomed in mineralization and none of them fully entered the primary sulphide zone. Mineralization is open down dip and along strike although the West Zone appears to be feathering out to the SE and other zones remain to be tested.
The good grades in the oxide zone represent the oxidation of an enrichment blanket, consisting mostly of covellite. Mineralization is associated with potassic alteration and albitization while the wall rocks exhibit calci-sodic alteration.
Acid solubilities in the oxide zones are good at 76% for all assays greater than 0.1%CuT and rising to 81% for all samples greater than 0.3%CuT. This is consistent with previous third party preliminary column test work carried out from surface samples which indicated ~75-85% CuT recovery and ~20-40kg/t net acid consumption.
Sampling and Assay Protocol
True widths cannot be determined with the information available at this time. Coro RC holes were sampled on a 2 m continuous basis, with dry samples riffle split on site and one quarter sent to the Geolaquim laboratory in Copiapo, Chile by Coro personnel for preparation and assaying. A second quarter was stored on site for reference. Samples were prepared using the following standard protocol: drying, crushing to better than 80% passing -10#, homogenizing, splitting and pulverizing a 400 g subsample to 95% passing -150#. All holes were assayed for CuT (total copper) and CuS (acid soluble copper) by AAS. A full QA/QC program, involving insertion of appropriate blanks, standards and duplicates was employed with acceptable results.
Sergio Rivera, Vice President of Exploration, Coro Mining Corp, a geologist with more than 32 years of experience and a member of the Colegio de Geologos de Chile and of the Instituto de Ingenieros de Minas de Chile, was responsible for the design and execution of the exploration program and is the Qualified Person for the purposes of NI 43-101. Alan Stephens, FIMMM, President and CEO, of Coro Mining Corp, a geologist with more than 40 years of experience, and a Qualified Person for the purposes of NI 43-101, is responsible for the contents of this website page.