Coro Mining Corp. ("Coro" or the "Company") is pleased to announce the results of a further 7 reverse circulation (RC) holes from the 39 hole, 8530m hole program completed at its Marimaca copper project, located 22km E of the port of Mejillones in the II Region of Chile, (Fig. 1). We also announce the results of the remaining 4 diamond drill (DDH) holes of the 6 hole, 2021m program, aimed at providing metallurgical samples and geotechnical information; to corroborate the RC drilling; and to test deeper mineralization. Previous drill results (MAR-01 to MAR-21, MAR-24 to 26 and MAD-01 to 02B) were released on April 28, May 6 and September 6 2016, and results for the remaining 24 RC holes will be released over the coming weeks.
Coro has agreed a 1 month extension to October 24 2016 for its due diligence period for the Minera Rayrock (MR) acquisition announced on August 4 2016; MR is the owner of the Ivan SXEW plant located some 18km S of Marimaca, as well as a large claim position shown on Fig. 1. Coro also announces that Minera Peñoles de Chile Ltda. has terminated its option over the Company's Llancahue prospect in central Chile.
Alan Stephens, President and CEO of Coro commented, "We are delighted with this latest batch of results from Marimaca, which continue to exceed our initial expectations for the deposit, both in thickness and grade. So far, drilling has only defined the SW limit of the mineralization, corresponding to the structural footwall of the deposit at surface. We will shortly be completing a drone based magnetic survey which we anticipate will further aid our understanding of the deposit and an initial resource estimate is scheduled for completion before year end."
Latest results are shown on Tables 1a and 1b where %CuT means total copper. Drill hole locations are shown on Fig. 2 and in more detail on Fig. 3. Drill collars for all holes are shown on Table 2.
Geology & Mineralization
The Marimaca deposit comprises a significant oxidised enrichment blanket, with some of the enrichment partially or completely preserved as mixed and enriched zones respectively. Primary chalcopyrite mineralization has been intersected in some of the deeper holes. The overall control to mineralization is a major N-S trending ~60°E dipping zone of fracturing, defined as the Marimaca Structure, cross cut by NE-SW oriented feeder structures, dipping to the SE. The host rock is a coarse grained Jurassic diorite intruded along the Structure by later diorite plugs and associated dykes that are related to the mineralization, all cross cut by post mineral andesitic sills and dykes. Strong potassic alteration and magnetite introduction accompanies the mineralization. Acid solubilities in the oxide zone are good at 74% for all assays > 0.1%CuT and rising to 80% for >0.3%CuT.
Coro has the right to earn a 75% interest in the property as follows;
- 51% interest earned in Compañia Minera Newco Marimaca (CMNM) with a $125k payment together with completion of a NI43-101 resource estimate and engineering study that demonstrates the technical and economic feasibility of producing a minimum of 1.5ktpy Cu cathode by August 6th 2018 at Coro's cost,
- Additional 24% interest in CMNM earned by Coro 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 Coro to loan them the equity portion corresponding to their 10% interest, if any, recoverable by Coro from 100% of the project's free cash flow after debt repayments
Twin Hole Analysis
Five of the DD holes were twinned with prior RC holes as follows; MAD-01/MAR-10, MAD-02/MAR-11, MAD-03/MAR- 03, MAD-05/MAR-04 and MAD-06/MAR-07. Recoveries in both RC and DD drilling exceeded 90%. Down hole surveying showed that the RC holes steepened more than the DD holes so that with increasing depth, the vertical separation invalidated the twinning exercise. However for the upper parts of the twins, there was good correlation between DD and RC holes and assays from both drilling methods will be used in the resource estimate.
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. Core from DDH holes was photographed, logged, split and sampled on site by Coro personnel and one half of the core sent to Geolaquim. Samples were prepared using the following standard protocol: drying; crushing to better than 85% passing -10#; homogenizing; splitting; pulverizing a 500-700g subsample to 95% passing -150#; and a 125g split of this sent for assaying. All samples 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. Samples showing significant secondary sulphides will be assayed for CuCN (cyanide soluble copper) in due course. Pulps and sample rejects are stored by Coro for future reference.
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 news release.
To view Fig 1: Location of Marimaca and Minera Rayrock Claims, please visit the following link: http://media3.marketwire.com/docs/1004CORO_map1.jpg
To view Fig 2: Marimaca Drill Plan, Latest RC holes in pink, DDH holes in blue, previous RC holes in brown and remaining RC holes in black, please visit the following link: http://media3.marketwire.com/docs/1004CORO_map2.jpg
To view Fig 3: Detailed drill plan showing latest RC holes in pink, DDH holes in blue, previous RC holes in brown, remaining RC holes in black, please visit the following link: http://media3.marketwire.com/docs/1004CORO_map3.jpg
Table 2: Marimaca Drill Collars