Bramaderos Update - Latest Limon assays indicate drilling is closing in on centre of gold-copper porphyry
OTTAWA, Dec. 03, 2019 - 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 (Figure 1), which it is exploring together with ASX listed Sunstone Metals Inc. under a farm-in 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:
- Assay results from drill hole LMDD004 indicate that drilling is now close to a gold-copper porphyry centre.
- Assays include 40m1 at 0.1g/t gold, 0.12% copper and 19ppm molybdenum, from 863m down hole, indicating that drilling is within the outer halo of a mineralized porphyry gold-copper system of significant scale.
- Drill holes BMDD004 and BMDD005 have been completed with both intersecting long intervals containing fine-grained chalcopyrite with assays pending.
- BMDD005 extends mineralization 150m northwest of BMDD001 which intersected 172m at 0.52g/t gold and 0.16% copper from surface. The strike extent of mineralization in holes BMDD001, 002 and 005 is now more than 300m and open in all directions.
- Processing of detailed ground magnetics, in conjunction with recent drilling, has further refined the interpretation of the geometry of Bramaderos Main.
- Assay results and interpretation of the West Zone epithermal system are expected in the second half of December.
Assay results from drill hole LMDD004 at Limon (Figure 2) have delivered a long interval of highly anomalous copper and gold values over 360m from 703m down hole, to the end of hole (Table 1). Low grade mineralization is open at depth.
LMDD004 intersected a sequence of magmatic and hydrothermal breccias and altered intrusive rocks (phyllic and argillic altered diorites). Vein intensity was mostly low averaging 2 quartz veins per metre over the 340m interval from 700m to 1040m depth, but locally averaging 25 quartz veins/metre within a narrow potassic-altered quartz diorite dyke. The lower part of the hole contained intervals of intense pyrite mineralization with minor chalcopyrite within a broader phyllic alteration zone.
These results are significant and strengthen the belief that this drill hole, LMDD004, and previously reported drill hole LMDD002, have drilled in close proximity to, and within the outer halo of, a mineralized porphyry gold-copper system of significant scale.
The long mineralized intervals in both holes are approximately 250m apart.
3-D modelling of recently collected detailed ground magnetic data has identified a target located beneath the central parts of holes LMDD002 and LMDD004.
This area is being targeted by drill hole LMDD006 (drill hole LMDD005 was commenced to drill this target but was abandoned due to drill string failure at 289.65m). LMDD006 is expected to be completed in January 2020.
At the Bramaderos Main target, drill holes BMDD004 and BMDD005 have recently been completed (Figure 4) and assays are pending (expected in January 2020). Both have intersected wide intervals containing copper mineralization as chalcopyrite.
High resolution ground magnetic data has been processed and has undergone first-pass modeling (Figure 4). Initial interpretation indicates that the magnetic model is tracking the higher-grade northeast limb of the porphyry system to depth well below the extent of current drill testing.
BMDD006 has commenced and is testing the area north-west of BMDD005 (Figure 4).
Cornerstone VP Exploration Yvan Crepeau said:
“The drilling results from Limon and Bramaderos Main strengthen our view that both areas are highly prospective for gold-copper porphyry-hosted mineralization. The higher resolution ground magnetics have allowed us to further refine target definition.
“Geological and assay results from Limon hole LMDD004 are telling us we are close to a mineralized porphyry system. We are seeing highly anomalous gold and copper grades over long intervals that suggest we are close to the main mineralizing system.
“We are comfortable with the depth implications at Limon, because when combined with an outcropping gold-copper system already partially defined at Bramaderos Main, the two targets, if large enough, can deliver a compelling development scenario. And we still have the giant Porotillo target to test.”
Table 1: Significant Assays from LMDD004 (Limon):
|From (m)||To (m)||Interval (m)||True Width (m)2||Gold (g/t)||Copper (%)||Molybdenum (ppm)|
Table 2: Drill hole details for the Bramaderos Project to date:
|Drill Hole Number||Start Date (dd/mm/year)||Completion Date (dd/mm/year)||Dip (degrees)||Azimuth (PSAD56 Grid) (degrees)||EOH (m)||Notes|
|LMDD003||8/8/19||8/14/19||-69||200.5||130.48||Abandoned, hole collapse|
|LMDD006||11/26/19||-77||244||In progress, targeted 1100m|
|BMDD006||11/27/19||-35||145||In progress, targeted 500m|
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 (the project operator) and 49% by Cornerstone.
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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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 True widths are estimated, but cannot be determined accurately at this time from the limited number of holes drilled.