Drilling at Limon target suggests major porphyry source nearby
OTTAWA, Oct. 15, 2019 (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 a farm-in agreement (see “About Bramaderos”, below).
Figures and plates 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:
- Encouraging assays received for the 0-222m downhole interval1 of Limon Drill Hole # 4 (LMDD004) with the remaining assays expected by mid-November
- LMDD004 intersected an upper ‘high-sulphidation’ copper system, likely of blanket geometry. Assays include:
- 13.3m at 0.43% copper and 0.11g/t gold from 57.8m, within an interval of 59.6m grading 0.16% copper
- 13.3m at 0.43% copper and 0.11g/t gold from 57.8m, within an interval of 59.6m grading 0.16% copper
- LMDD004, which was terminated at 1,063m, also intersected altered rocks with weak mineralization in close proximity to a porphyry system, along with breccias containing clasts of mineralized porphyry
- Drilling will resume at Bramaderos Main next week to follow-up BMDD002 that intersected 164m at 0.52g/t gold and 0.16% copper and 63m at 0.5g/t gold and 0.19% copper (see Cornerstone news release dated August 20, 2019)
The geological and partial assay results from hole LMDD004 are significant for a number of reasons:
- The hole intersected a copper +/- gold ‘high sulphidation’ epithermal system in a shallow position that could develop into an exploration target in its own right. Geologically ‘high sulphidation’ systems can develop in a variety of styles, all related to porphyry systems. Examples include Tampakan and Lepanto in the Philippines, the Tujuh Bukit gold-silver oxide system in Indonesia, and the Yanacocha deposit in Peru.
- There is alteration in the deeper parts of hole LMDD004, suggesting close proximity to a porphyry system and combined with observations from LMDD002, further strengthen the vectors to mineralization.
- Weak mineralization and veining have been identified over several intervals in LMDD004.
- Detailed ground magnetics data across the Limon Prospect have been collected and are being processed to provide greater clarity on target parameters.
- With 3 drill holes and more detailed magnetics data a 3-D interpretation of Limon is emerging.
- In the context of the district scale exploration model (see Cornerstone news release dated August 27, 2019) these results strongly reinforce the significant exploration potential at Limon. The juxtaposed epithermal high sulphidation copper blanket, with hydrothermal breccias sourcing a porphyry system, in the vicinity of outcropping stockwork B-veins returning 97.6m at 0.71g/t gold and 0.23% copper (see Cornerstone news release dated May 29, 2018) supports the strong optimism for discovery.
- Figures 1 and 2 show the context for LMDD004 within the cluster of porphyry systems at the Bramaderos Project. Importantly, there are a series of targets which are being systematically explored. The targets range from outcropping mineralization at Bramaderos Main, with a current minimum vertical extent of mineralization of 300m but expected to be much greater, sub-outcropping at Porotillo, Gangue and Playas, to deeper, but with a shallow mineralized epithermal high sulphidation blanket, at Limon.
- While the main Limon porphyry system is now interpreted to be >500m below surface, we do know that portions of the system extend to surface as evidenced by the results from trench LM-01 which intersected 97.6m at 0.71g/t gold and 0.23% copper. Our exploration program will look to define the areas of mineralization across this vertical interval.
Cornerstone Vice President, Exploration, Yvan Crepeau said:
“These latest results provide more evidence that we are closing in on a large porphyry system. This is just the third hole2 we have drilled at Limon, but the combination of this blanket mineralization, the large anomalies in multiple surface datasets and the discovery of mineralized porphyry clasts in breccias indicate a large porphyry system being present. It is still early days at Limon, but a very encouraging model is emerging.”
Bramaderos Project Update:
The results from Limon must also be considered in the context of the broader Bramaderos Project potential and presented in Cornerstone’s news release dated August 27, 2019. While the Limon porphyry target is delivering a deeper than expected target zone, the Bramaderos Main target is an outcropping porphyry system with the potential to deliver a significant scale deposit. Drilling is focused on that definition of scale. Similarly, nearby porphyry targets Porotillo, Gangue, Melonal, and Playas all have a degree of mineralization at surface and require modern exploration and drill testing.
Immediate activities are:
- At West Zone drilling is expected to be completed in late October, and first assay results are expected soon. An update will be provided once assays are received.
- Final assays for hole BMDD002 at Bramaderos Main are expected very soon and drilling will resume at Bramaderos Main next week to extend the area of previously drilled mineralization which returned 164m at 0.52g/t gold and 0.16% copper and 63m at 0.5g/t gold and 0.19% copper (see Cornerstone news release dated August 20, 2019).
- Limon drilling will continue into the porphyry target zone shown on Figure 3.
The broad sequence intersected in LMDD004 comprises an overlying sequence of volcanic rocks that are altered to clay and silica assemblage, often associated with the high levels of a porphyry and overlying epithermal system.
Two broad zones of magmatic-hydrothermal breccia were intersected in the upper and middle parts of the hole (see Figure 4). They contain some clasts with porphyry-related quartz veins, indicating parts of a porphyry system lie at greater depth below the breccia.
Deeper in the hole the alteration intensifies to suggest increasing proximity to a porphyry system.
As concluded from the results of hole LMDD002, these results to strongly suggest we have drilled ‘beside’, and in close proximity to, a mineralized porphyry system.
Significant results within the top 222m of LMDD004 include:
|From (m)||To (m)||Interval (m)||Gold (g/t)||Copper (%)|
Drill hole details for the Limon prospect:
|Drill Hole Number||Start date (dd/mm/year)||Completion date (dd/mm/year)||Dip (degrees)||Azimuth (degrees)||EOH (m)||Notes|
|LMDD003||8/7/2019||8/14/2019||-69||200.5||130.48||Abandoned, hole collapse|
Measuring 4,949 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 51% by Sunstone and 49% by Cornerstone, Sunstone having earned its initial 51% interest by spending US$3.4 million over 3 years to complete a phase 1 drill program. Sunstone has 90 days (i.e., until November 27, 2019) to elect to earn an additional 19% to go to 70% by funding a bankable feasibility study within 5 years, and can go to 80% by financing 100% of the cost of construction of a mine and mill (see Cornerstone news releases dated April 10, 2017 and August 28, 2019).
Sunstone is the project operator.
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 in the Cascabel gold-enriched copper porphyry joint venture in north west Ecuador.
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 cannot be determined at this time from the limited number of holes drilled.
2 Three holes, LMDD001, 002, and 004. Hole LMDD003 was abandoned at 130.48m due to hole collapse and was not assayed due to poor sample recovery.