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Bramaderos Au Cu Project, Ecuador – Latest assays combined with new 3D magnetics point to clusters of higher-grade zones

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Bramaderos Au Cu Project, Ecuador – Latest assays combined with new 3D magnetics point to clusters of higher-grade zones






Cornerstone Capital Resources Inc. (TSX-V-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 ( or by clicking on the link below:




  • Diamond drilling results from the wider Bramaderos Hill area (which includes the Bramaderos Main prospect), extend gold and copper mineralization to over 1km in length (Figure 1)
  • This larger area has been re-named the ‘Brama target’ (Figure 2)
  • Assays from drill hole BMDD007 include:

° 181.7m (true width1 “tw” 127m) at 0.43g/t gold and 0.1% copper from 55.7m, including

  • 51.8m (tw 36m) at 0.47g/t gold and 0.11% copper from 55.7m, and
    · 33.4m (tw 23m) at 0.47g/t gold and 0.11% copper from 125.3m, and
    · 40.6m (tw 28m) at 0.49g/t gold and 0.11% copper from 170.6m,
  • Mineralization remains open to the north-west and south-east
  • These latest results, combined with an in-depth review of 3D magnetic data, indicate a cluster of higher-grade targets within a very large lower-grade gold-copper domain at Brama


Cornerstone VP Exploration, Yvan Crepeau, said:

“We have indicated a potential for a large gold-copper mineralized body at the Brama target. Within this body that is estimated to be 1,000m x 500m are several higher-grade zones. This is consistent with the new 3-D magnetic model and provides the basis for planning additional drilling to target  >0.5g/t gold and >0.1% copper domains.


The development of this model at Brama will also apply at our 5 other large porphyry targets within the Bramaderos Project. We are seeing similar patterns at Limon, Playas, Melonal, Porotillo, and Sandia targets. We are confident that clusters of higher-grade zones are to be discovered at potentially all of these targets.


We have early indications of this at Porotillo through historic drill holes, that delivered 26m at 1.1g/t gold and 0.16% copper from 6m downhole in CURI-05.”




Assays from hole BMDD007 identify mineralized intervals that correlate with relatively more magnetic bodies. Detailed analysis of the 3-D magnetic model identifies clusters of these more magnetic bodies at Brama, and at the other 5 porphyry targets within the Bramaderos project (Figure 3).


Significant assays from BMDD007 include:



Hole ID From To Interval True Width Au (g/t) Cu (%) Ag (g/t)
BMDD007 8 515.8 507.8 355.4 0.22 0.06 0.69
incl. 8 240 232 162.4 0.39 0.09 1.01
and 55.7 237.4 181.7 127.2 0.43 0.1 1.03
incl. 55.7 107.5 51.8 36.3 0.47 0.11 1.36
and 125.3 158.65 33.35 23.4 0.47 0.11 1.01
and 170.65 211.2 40.55 28.4 0.49 0.11 1.00


At the Limon target, drill hole LMDD006 has been completed at 1212.62m. Assay results are expected to be available during March.


About Bramaderos


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 which 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).


Qualified Person:


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


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.


About Cornerstone:


Cornerstone Capital Resources Inc. is a mineral exploration company with a diversified portfolio of projects in Ecuador and Chile, including in the Cascabel gold-enriched copper porphyry joint venture in north west Ecuador.



Posted February 25, 2020

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