Bramaderos Au Cu Project, Ecuador – Exploration breakthrough leads to identification of numerous higher grade gold-copper porphyry targets
Temporary suspension of activities at Bramaderos due to Coronavirus Precautions
OTTAWA, March 26, 2020 (GLOBE NEWSWIRE) — Cornerstone Capital Resources Inc. (“Cornerstone” or “the Company”) (TSXV-CGP) (F-GWN) (B-GWN) (OTC-CTNXF) is pleased to provide an update on its Bramaderos gold and copper project in southern Ecuador, which it is exploring together with ASX listed Sunstone Metals Inc. under joint venture agreement (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:
- Detailed technical review leads to a breakthrough in understanding the multiple gold-copper porphyry deposits identified within the Bramaderos concession
- The findings stem from a review of drilling results, more detailed magnetic data, and 3-D modeling
- The evidence suggests that the porphyry systems exhibit pipe-like geometry similar to many other porphyry deposits, such as Northparkes in Australia, and others globally
- Exploration to date had been based on the belief that the porphyries at Bramaderos have broad, widely disseminated geometries, which are common elsewhere such as in Chile
An in-depth review of all exploration data from Bramaderos has resulted in a breakthrough, that has led to the identification of numerous, compelling drill targets.
The review found that the higher-grade gold-copper porphyries exhibit pipe-like geometry, not broad, disseminated geometry as previously believed.
Some leading porphyries globally display this geometry, while many other porphyries, such as those in Chile and Asia, exhibit broader disseminated geometries (on which the original exploration model for Bramaderos was based).
These geometries for pipe-like or ‘pencil porphyry’ style porphyry gold-copper systems are not unusual and better-known examples include the Northparkes mine in NSW, the Skouries deposit in Greece, and the Boyongan deposit in the Philippines. These deposits are typically smaller individually but cluster as multiple deposits and deliver higher grades.
Cornerstone VP Exploration, Yvan Crepeau, said:
“Project operator Sunstone’s technical review of results to date from Bramaderos has delivered some compelling new interpretations of the gold-copper porphyry systems within the project. Some have been real ‘eye openers’ such as the detailed ground magnetics and associated 3-D modeling. In isolation this is a standard exploration evolution, but combined with our drilling results to date, and surface sampling we have every reason to be optimistic about discovery. The interpretation of the geometry of these porphyry systems has been improved, and the potential for building significant tonnes, and at higher grades is greatly improved.”
Details of the Review
The review considered each of the 6 gold-copper mineralized systems within the Bramaderos project (Figure 1), and the 2 currently defined epithermal gold targets.
All of the gold-copper porphyry systems are mineralized (Figure 2) and the review focused on targeting the higher-grade domains within these systems.
The review has identified that a later higher-grade event can now be defined and is related to pipe like intrusive bodies that are mappable based on the 3-D modeling of the more detailed ground magnetics (Figure 3).
These pipe like bodies cluster within each system, so for example at Brama 5 targets exist and correlate with higher grade where drilled (Figure 4).
At Playas the pipe like magnetic bodies correlate with areas of highest grade gold and copper in surface samples giving us confidence that drilling will extend that mineralization to depth. Playas has never been drilled.
Melonal, Porotillo and Sandia all present similar relationships.
At Porotillo a historical drill hole (CURI-05) intersected 26m at 1.1g/t gold and 0.2% copper demonstrating that significantly higher grades can be delivered from these systems.
Limon Assay Results
Assay results from drill hole LMDD006 at Limon have been received. The drill hole intersected an upper high sulphidation gold interval of 131.3m (true width1 “tw” 91m) at 0.18g/t gold from surface, with individual samples of up to 1.6m thick grading 1.2g/t. Copper grades were locally anomalous with up to 0.16% copper and 0.4g/t gold over 0.9m widths. This high sulphidation interval is a correlative of that intersected in LMDD004 which returned 59m (tw 41m) at 0.16% copper from 57.8m down hole, including 13.3m (tw 9m) at 0.43% copper and 0.11g/t gold from 57.8m (see Cornerstone news release dated October 15, 2019).
Deeper intervals in LMDD006 intersected intensely phyllic altered intrusive rocks and breccias and only locally gold and copper anomalous intervals. Together with the results from holes LMDD002 and LMDD004 we are now seeing vectors that suggest a target zone to the south.
Suspension of activities at Bramaderos and other Cornerstone Projects due to Coronavirus Precautions and Ecuador State of Emergency
Exploration activities at the Bramaderos Project and other Cornerstone Projects in Ecuador (including Cascabel, the Enami Strategic Exploration Alliance, and Caña Brava) have been suspended in line with the directives of the Ecuadorian government decree declaring a nationwide emergency to manage the risks associated with the corona (Convid-19) virus.
Desktop activities by project operator and JV partner Sunstone Metals are ongoing to interpret data to move target areas towards being drill ready when the suspensions are lifted.
Measuring 4,948 hectares, the Bramaderos project is located approximately 130km from the Loja provincial capital in southern Ecuador. The project is easily accessible via the Pan American Highway that crosses the property.
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
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-20 is considered a near total 4 acid technique using a 20g 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. MS Analytical is an internationally accredited laboratory that has all its internal procedures heavily scrutinized in order to maintain their accreditation. MS Analytical is accredited to ISO/IEC 17025 2005 Accredited Methods.
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 9001-2008 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 MS Analytical Services (MSA), an ISO 9001-2008 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 (QA/QC)
The MSA Analytical Laboratory 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 22.2% 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 8.5% of the shares of joint venture partner and project operator SolGold Plc. Exploraciones Novomining S.A. (“ENSA”), 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.
Further information is available on Cornerstone’s website: www.cornerstoneresources.com and on Twitter. For investor, corporate or media inquiries, please contact:
Mario Drolet; Email: Mario@mi3.ca; Tel. (514) 904-1333
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This news release may contain ‘Forward-Looking Statements’ that involve risks and uncertainties, such as statements of Cornerstone’s beliefs, plans, objectives, strategies, intentions and expectations. The words “potential,” “anticipate,” “forecast,” “believe,” “estimate,” “intend”, “trends”, “indicate”, “expect,” “may,” “should,” “could”, “project,” “plan,” or the negative or other variations of these words and similar expressions are intended to be among the statements that identify ‘Forward-Looking Statements.’ Although Cornerstone believes that its expectations reflected in these ‘Forward-Looking Statements’ are reasonable, such statements may involve unknown risks, uncertainties and other factors disclosed in our regulatory filings, viewed on the SEDAR website at www.sedar.com. For us, uncertainties arise from the behaviour of financial and metals markets, predicting natural geological phenomena and from numerous other matters of national, regional, and global scale, including those of an environmental, climatic, natural, political, economic, business, competitive, or regulatory nature. These uncertainties may cause our actual future results to be materially different than those expressed in our Forward-Looking Statements. Although Cornerstone believes the facts and information contained in this news release to be as correct and current as possible, Cornerstone does not warrant or make any representation as to the accuracy, validity or completeness of any facts or information contained herein and these statements should not be relied upon as representing its views after the date of this news release. While Cornerstone anticipates that subsequent events may cause its views to change, it expressly disclaims any obligation to update the Forward-Looking Statements contained herein except where outcomes have varied materially from the original statements.
On Behalf of the Board,
President and CEO
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1 True widths are estimated, but cannot be determined accurately at this time from the limited number of holes drilled.