STM Sunstone Metals Limited

Cornerstone Capital Resources Inc. (“Cornerstone” or “the Company”) (TSXV: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:

https://cornerstoneresources.com/site/assets/files/5842/nr22-05figures.pdf.

HIGHLIGHTS:

• Combination of geophysics and drilling deliver a very large-scale target at Alba of known high gold-copper grades
• The geophysical survey results have also identified several nearby Alba-style targets which Sunstone is now preparing to drill
• In light of the survey results, Sunstone is increasing the number of rigs at Alba to three to accelerate drilling towards a Maiden Resource Estimate
• Drilling has produced exceptional results1, including:
  • 111m2 at 2.35g/t gold from 93m in BMDD0123
  • 264.7m at 0.49g/t gold and 0.13% copper, from 95m to end of hole in BMDD020
  • 223.7m at 0.58g/t gold and 0.13% copper, from 107.6m in BMDD021
  • 239.4m at 0.42g/t gold and 0.13% copper, from 82.5m to end of hole in BMDD022
  • 222.4m at 0.37g/t gold and 0.13% copper from 76.4m in BMDD023

Cornerstone VP Exploration, Yvan Crepeau, said:

“We already knew that Alba hosts high grades by porphyry standards and now it appears to have large scale, with the geophysical survey indicating the system continues from surface to more than 1km deep. Drilling has tested to only about 350m below surface.

“The survey also identifies several Alba-style targets nearby, that our funding partner and project operator, Sunstone Metals, is already preparing to drill.”

* 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.

FURTHER INFORMATION:

Wide and high-grade gold-copper intervals from holes BMDD012, 020, 021, 022, and 023 have been previously reported (see news releases dated November 18, 2021, January 20, 2022, and March 7, 2022).

Results (see also Figure 3) include broad intervals of:

• 111m at 2.35g/t gold from 93m in BMDD012
• 264.7m at 0.49g/t gold and 0.13% copper, from 95m to end of hole in BMDD020
• 223.7m at 0.58g/t gold and 0.13% copper, from 107.6m in BMDD021
• 239.4m at 0.42g/t gold and 0.13% copper, from 82.5m to end of hole in BMDD022
• 222.4m at 0.37g/t gold and 0.13% copper from 76.4m in BMDD023

But importantly also include high grade sub-intervals, close to surface of:

• 21.0m at 0.91g/t gold and 0.17% copper, from 203m in BMDD020
• 60.7m at 1.01g/t gold and 0.19% copper, from 136m in BMDD021
• An open interval in BMDD022 at the end of hole of 7.9m at 0.84g/t gold and 0.21% copper from 314m

Alba is a porphyry system partly overprinted by a lithocap, indicating much of the Alba system is likely preserved at depth with considerable vertical extent commencing from surface. This geological interpretation is supported by recently completed electrical geophysics (Spartan magneto-telluric survey) which maps a resistive domain that correlates well with the shallow high-grade gold-copper zone at Alba, and that extends to depths of greater than 1,000m (Figure 4).

Conventional pole-dipole IP maps a chargeable domain in the shallow portions of the mineralized body, giving confidence that the system has a lateral extent of at least 250m.

These patterns repeat in nearby targets. Additional similarly resistive domains are seen in the Spartan MT dataset near or coincident with other magnetic targets that have potential to be Alba-type analogues.

About Bramaderos

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.

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

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 (QA/QC)

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.

About Cornerstone

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. (“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:

Investor Relations:Mario Drolet; Email: Mario@mi3.ca; Tel. (514) 904-1333

Due to anti-spam laws, many shareholders and others who were previously signed up to receive email updates and who are no longer receiving them may need to re-subscribe at http://www.cornerstoneresources.com/s/InformationRequest.asp

Cautionary Notice: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 anti-mining sentiment in certain regions of Ecuador, or 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, Brooke MacdonaldPresident and CEO

Neither TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.

_________________________________1 See Table of Assay Results in news release 22-04 dated March 7, 2022.2 The true width of downhole intersections cannot be determined at this time due to insufficient drilling.3 See news release dated November 18, 202.