Coro Announces Final Results of Test Work for Planta Prat Project

Apr 13, 2015 | PDF

News Release 15-02 

April 13 2015, Marimaca Copper Corp.
(“Coro” or the “Company”) (TSX Symbol: COP) is pleased to report positive final results from test work carried out on a composite sample from the Planta Prat milled leach residue deposit, using proprietary technology developed by a subsidiary of ProPipe SA (“ProPipe”) in Chile. In addition, Marimaca Copperhas paid the $50k option payments for the Marimaca and Planta Prat projects as outlined in our news release dated March 18th 2015.

Alan Stephens, President and CEO of Marimaca Coppercommented, “We are delighted that the test work has indicated that an 81% recovery of total copper with an acid consumption of 18kg/t is achievable and that ProPipe’s technology can resolve the plant’s previous operating issues. We now intend to complete our evaluation of the project through resource definition, additional metallurgical test work and an engineering study. Subject to a positive outcome to these studies and availability of financing, our objective is to put Planta Prat back into production as soon as possible. We also look forward to advancing the Marimaca project through the initial drilling stage later this year.”

About Planta Prat
Planta Prat is a small agitation SXEW plant that was built in 2012 to retreat milled leach residues, located 33km NE of Antofagasta in the II Region of northern Chile. It suffered operational problems caused by a build-up of Fe sulphate emulsion in the SX circuit that caused the plant to cease production after a few months. Marimaca Copperhas the option to earn a 51% in the project by making a remaining $100k payment coincident with the expansion of the plant to a minimum 1.2ktpy Cu capacity on or before August 6th 2017, and will earn an additional 14% interest upon commencement of commercial production.

The test work comprised agitation leaching of the composite, which averaged 0.49%CuT / 0.46%CuS, to produce pregnant leach solution (“PLS”) followed by direct deposition of copper from the PLS onto cathodes in a proprietary EW circuit. Various combinations of solid density and acid concentration were tested and optimum results were obtained from a 45% solids density pulp and a 30g/l acid concentration. This resulted in an 84.4% recovery, which is estimated to translate to 81% recovery of CuT in industrial conditions, with a 15 minute residence time, and an acid consumption of 18kg/t. Several EW tests were also carried out using the proprietary technology, with optimum cathode production achieved with a concentration of 20 g/L de Cu2+ at 50°C and with a current density of 200 A/m2. It is estimated that 18 EW cells and 22 x 1m2 cathodes would be required to produce 1.5ktpy of copper.

About Marimaca
Marimaca is an early stage copper oxide project hosted by Jurassic intrusive rocks, located 56km N of Antofagasta and ~22km from the coast at Mejillones, in the II Region of northern Chile. Surface sampling and geological mapping indicates that oxide copper mineralization occurs within an eastward dipping shear structure, some 250m in estimated true thickness and exposed over at least 600m. It is currently being exploited in a series of small open pits over a vertical elevation difference of 100-150m by mechanized artisanal miners. As described in our news release of October 30th 2014, the weighted average of 365m of chip channel samples taken at various places along the exposed strike length is 0.49%CuT/0.36%CuS, including an internal waste section.

Marimaca Copperhas the option to earn a 51% interest in the project by making a remaining payment of $125k coincident with the completion of a resource estimate to Canadian standards and engineering study that demonstrates the technical and economic feasibility of producing a minimum of 1.5ktpy Cu cathode by August 6th 2018, and an additional 24% interest upon obtaining financing for the project construction. The owner’s interest will comprise a 15% interest, free carried to commencement of commercial production, and a 10% participating interest subject to dilution. The owners, at their election, may request Marimaca Copperto loan them the equity portion corresponding to their 10% interest, if any, recoverable by Marimaca Copperfrom 100% of the project’s free cash flow after debt repayments.

Alan Stephens, FIMMM, President and CEO, of Marimaca Copper Corp, a geologist with more than 39 years of experience, and a Qualified Person for the purposes of NI 43-101, is responsible for the contents of this news release.

About Coro
Coro’s strategy is to grow a mining business through the discovery, development and operation of “Marimaca Coppertype” deposits. These are defined as projects at whatever stage of development, that are well located with respect to infrastructure and water, which have low permitting risk, and which have the potential to achieve a short and cost effective timeline to production. Our preference is for open pit heap leach copper projects, where we will seek to minimise capital investment rather than maximise NPV, where we will prioritise profitability over production rate, and finally, where the likely capital cost is financeable relative to our market capitalization. Partners will be sought for any attractive projects identified that we do not have the financial capacity to develop alone. Coro’s properties include the Berta pre-production project, the Planta Prat copper development project and the Marimaca copper exploration prospect, all located in Chile. The advanced San Jorge copper-gold project located in Argentina is being sold to Aterra Capital and Solway Industries while the Llancahue copper exploration prospect in south-central Chile has been optioned to Peñoles.


“Alan Stephens”

Alan Stephens
President and CEO

For further information please visit the Company’s website at or contact Michael Philpot, Executive Vice-President at (604) 682 5546 or

This news release includes certain “forward-looking statements” under applicable Canadian securities legislation. Such forward-looking statements or information, including but not limited to those with respect to the recoveries, acid consumption, metallurgical results and production, involve known and unknown risks, uncertainties, and other factors which may cause the actual results, performance or achievements of the Company to be materially different from any future results, performance or achievements expressed or implied by such forward-looking statements or information. Such factors include, among others, the actual price of copper, the factual results of current and future exploration, development and mining activities, changes in project parameters as plans continue to be evaluated, as well as those factors disclosed in the Company’s documents filed from time to time with the securities regulators in the Provinces of British Columbia, Alberta, Saskatchewan, Manitoba, Ontario, New Brunswick, Nova Scotia, Prince Edward Island and Newfoundland and Labrador.

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