Cornerstone Capital Resources Inc. (TSX-V:CGP) (OTC:CTNXF) (FWB:GWN1) is pleased to provide an update on its Bramaderos gold and copper joint venture in southern Ecuador (see Figures 1 and 2) in which it has a 12.5% interest carried by JV partner and project operator Sunstone Metals Inc. (ASX: STM) through to the start of commercial production (see “About Bramaderos”, below).
Figures related to this news release can be seen in PDF format by accessing the version of this release on the Company’s website (www.cornerstoneresources.com) or by clicking on the link below:
264.7m1 at 0.49g/t gold and 0.13% copper, from 95m to end of hole; including:
Hole BMDD020 is only the second hole drilled at the Alba gold discovery, returning a 193.7m porphyry intersection grading 0.5g/t gold and 0.16 per cent copper from 164m. Mineralization remains open at depth.
Hole BMDD020 was drilled below maiden hole BMDD012, which returned 111m at 2.3 g/t, including 7.2m at 26.88 g/t (see Cornerstone news release 21-20 dated November 18, 2021). Hole BMDD020 also intersected the Upper Gold Zone returning 7.0m at 1.77g/t gold.
The results indicate that the Alba discovery comprises a gold zone sitting above a well mineralized gold-copper porphyry that remains open and largely untested. The Upper Gold Zone is currently interpreted to be a structurally controlled epithermal system. A geological model is being developed for this system, but the current understanding is shown graphically in Figures 3 and 4. Petrographic studies are underway.
Visible gold was identified in drill holes BMDD012 and 020 (Figure 2), and importantly in BMDD020 it was observed in both the Upper Gold Zone and within the broader porphyry zone leading to the potential for future high grade gold intervals.
Additional follow-up drill holes BMDD021 and 022 at Alba have been completed, and hole BMDD023 is well advanced (Figures 3 and 4) and are being sampled for laboratory submission. All holes have intersected rock types and alteration similar to that documented in holes BMDD012 and 020. The drill holes appear to have drilled the equivalent of the Upper Gold Zone (significant anhydrite veining), and well developed stockwork at depth with some visible copper sulphides representing the porphyry zone.
Cornerstone VP Exploration, Yvan Crepeau said:
“The latest results provide further indications that Alba is emerging as a major discovery, and demonstrate the presence of an Upper Gold Zone above a well-mineralized porphyry.
“These are some of the best porphyry gold-copper results we have seen in the broader Bramaderos Project. We are also seeing local visible gold within the porphyry system, which is highly encouraging.
“The Upper Gold Zone at Alba will be further defined as we undertake additional drilling. It is likely to be structurally controlled, and we are testing NE and N-S oriented structures from interpretation of magnetics.
“We are also undertaking detailed electrical geophysics to help map the distribution of the Upper Gold Zone, and the porphyry mineralization. We are getting hints that there is lateral continuity, and the target area is wide open.”
Assay results to date from Alba include:
|Drill Hole||From (m)||To (m)||Interval (m)||Au (g/t)||Cu (%)||Mo (ppm)||Ag (g/t)|
* The reader is cautioned that there has been insufficient exploration to define a mineral resource at Bramaderos and it is uncertain if further exploration will result in the target being delineated as a mineral resource.
Visible gold was also identified in drill hole BMDD013 and correlated with an interval of 2m at 2g/t gold, located approximately 100m from the BMDD012 and BMDD020 Upper Gold Zone intervals.
The Upper Gold Zone is currently interpreted as a late-stage gold-rich event superimposed over a broad and deeper gold-copper porphyry mineralized system. The grades in the porphyry system in BMDD020 are some of the best seen at Bramaderos since project operator Sunstone commenced drilling. This is very encouraging as exploration is advanced across the broader Alba target.
A conventional IP survey comprising 6 x 1,600m long lines has been planned for the Alba target and is expected to commence in late January. A 3-D Magnetotellurics survey will also be undertaken over the Alba target. MT is a geophysical method which uses natural time variations of the Earth’s magnetic and electric fields to measure the electrical resistivity of the sub-surface. Application of MT in exploration for porphyry systems has advanced significantly over the last several years and it is anticipated that the combination of MT and conventional IP will deliver multiple drill targets for both porphyry gold-copper mineralization and overprinting epithermal systems, as currently interpreted at Alba.
Measuring 4,948 hectares, the Bramaderos project is ideally located immediately adjacent to the Pan American highway, and within reasonable distance of available hydropower, supporting the economics of potential development opportunities. The project is also supported by nearby commercial airports and significant cities (Loja) and enjoys strong community support.
The Bramaderos concession is owned by La Plata Minerales S.A. (“PLAMIN”), which in turn is owned 87.5% by Sunstone (the project operator) and 12.5% by Cornerstone.
Cornerstone’s 12.5% interest is carried by Sunstone through to the start of commercial production and repayable at Libor plus 2% out of 90% of Cornerstone’s share of earnings or dividends from the Bramaderos project (see news release 20-01 dated January 7, 2020).
More information about the property can be found at www.cornerstoneresources.com.
Yvan Crepeau, MBA, P.Geo., Cornerstone’s Vice President, Exploration and a qualified person in accordance with National Instrument 43-101, is responsible for supervising the exploration program at the Bramaderos project for Cornerstone and has reviewed and approved the information contained in this news release.
Sampling and Assaying
Surface and drill core samples from Brama were sent to the LAC y Asociados Cia. Ltda. Sample Preparation Facility in Cuenca, Ecuador for sample preparation. The standard sample preparation for drill core samples (Code PRP-910) is: Drying the sample, crushing to size fraction 70% <2mm and splitting the sample to a 1000g portion by riffle or Boyd rotary splitter. The 1000g sample is then pulverised to >85% passing 75 microns and then sent to the MSALABS in Langley, BC, Canada for gold and base metal analysis.
PLAMIN uses a fire assay gold technique for Au assays (FAS-111) and a four acid multi element technique (IMS-230) for a suite of 48 elements. FAS-111 involves Au by Fire Assay on a 30-gram aliquot, fusion and atomic absorption spectroscopy (AAS) at trace levels. IMS-230 is considered a near total 4 acid technique using a 0.25g aliquot followed by multi-element analysis by ICP-AES/MS at ultra-trace levels. This analysis technique is considered suitable for this style of mineralization.
Standards, blanks and duplicates are inserted ~1/28 samples. The values of the standards range from low to high grade and are considered appropriate to monitor performance of values near cut-off and near the mean grade of the deposit. The check sampling results are monitored and performance issues are communicated to the laboratory if necessary.
Sample security was managed through sealed individual samples and sealed bags of multiple samples for secure delivery to the laboratory by permanent staff of the joint venture. MSALABS is an internationally accredited laboratory that has all its internal procedures heavily scrutinized in order to maintain their accreditation. MSALABS is accredited to ISO/IEC 17025-2017 Accredited Methods and certified to ISO 9001-2015.
PLAMIN’s sampling techniques and data have been audited multiple times by independent mining consultants during various project assessments. These audits have concluded that the sampling techniques and data management are to industry standards. All historical data has been validated to the best degree possible and migrated into a database.
Rock samples are collected by PLAMIN’s personnel, placed in plastic bags, labeled and sealed, and stored in a secure place until delivery by PLAMIN employees to the LAC y Asociados ISO 9001-2015 certified sample preparation facility in Cuenca, Ecuador.
Rock samples are prepared crushing to 70% passing 2 mm (10 mesh), splitting 250 g and pulverizing to 85% passing 75 microns (200 mesh) (MSA code PRP-910). Prepared samples are then shipped to MSALABS, an ISO/IEC 17025-2017 Accredited Method company and ISO 9001-2015 laboratory in Langley, BC, Canada, where samples are assayed for a multi-element suite (MSA code IMS-136, 15.0 g split, Aqua Regia digestion, ICP-AES/MS finish) and gold by Fire Assay (MSA code FAS-111, 30 g fusion, AAS finish). Over limit results for Cu (>1%) are systematically re-assayed (MSA code ICF-6Cu, 0.2 g, 4-acid digestion, ICP-AES finish). Gold is assayed using a 30 g split, Fire Assay (FA) and AAS finish (MSA code FAS 111). Over limit results for Au (>10 g/t) are systematically re-assayed (MSA code FAS-415, FA, 30g., gravimetric finish).
Soil samples are dried at low temperature, screened to 80 mesh (MSA code PRP-757); a 15 grams portion is then assayed for a multi-elements suite (MSA code IMS-136, Aqua Regia digestion, ICP-AES/MS finish).
Quality Assurance / Quality Control
MSALABS is a qualified assayer that performs and makes available internal assaying controls. Duplicates, certified blanks and standards are systematically used (1 control sample every 20-25 samples) as part of PLAMIN’s QA/QC program. Rejects, a 100 g pulp for each rock sample, are stored for future use and controls.
Cornerstone Capital Resources Inc. is a mineral exploration company with a diversified portfolio of projects in Ecuador and Chile, including the Cascabel gold-enriched copper porphyry joint venture in northwest Ecuador. Cornerstone has a 20.8% direct and indirect interest in Cascabel comprised of (i) a direct 15% interest in the project financed through to completion of a feasibility study and repayable at Libor plus 2% out of 90% of its share of the earnings or dividends from an operation at Cascabel, plus (ii) an indirect interest comprised of 6.86% of the shares of joint venture partner and project operator SolGold Plc. Exploraciones Novomining S.A. an Ecuadoran company owned by SolGold and Cornerstone, holds 100% of the Cascabel concession. Subject to the satisfaction of certain conditions, including SolGold’s fully funding the project through to feasibility, SolGold Plc will own 85% of the equity of ENSA and Cornerstone will own the remaining 15% of ENSA.
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