Latest Metallurgical Test Results Exceed 95% Vanadium Extraction from Cornerstone Metals Inc.'s Carlin Vanadium Project

Vancouver, British Columbia--(Newsfile Corp. - June 20, 2018) - Cornerstone Metals Inc.(TSXV: CCC) (OTCQB: CCCCF) (FSE: 1PY)("Cornerstone" or the "Company") is pleased to announce additional preliminary results of metallurgical test work being conducted on its Carlin Vanadium Project in Nevada. The third round of testing has achieved vanadium extraction levels of 95.5%.

"Our testing has very quickly moved the needle from the low 80's, which were strong, to outstanding numbers, far exceeding even our metallurgists' expectations," said Cornerstone President and Chief Executive Officer, Paul Cowley. "These numbers show a clear sign of a major technical breakthrough for our project."

Test work continues on a sample composite generated from an 18.9 metre drill core intercept from the Company's recent diamond drilling verification program on the deposit. The latest results employed a roast/leach/pressure oxidation approach. Ongoing test work will continue to optimize various parameters with the aim of developing a conceptual flowsheet. Once a conceptual flowsheet has been defined, tests will be run across the deposit on a full range of samples. The tests to date have been conducted to demonstrate potential recoveries. At this stage, there is no suggestion that these tests demonstrate economic viability.

Metallurgical test work continues at Sherritt Technologies in Fort Saskatchewan, Alberta, the leader in the development and commercialization of pressure hydrometallurgical processes. Sherritt is a one-stop shop that has a proven track record of developing projects from concept-to-operation with a skilled and experienced team, including process and equipment specialists.

The Carlin Vanadium deposit is considered one of the largest, highest grade primary vanadium deposits in North America (USGS Professional Paper 1802 Critical Mineral Resources of the United States—Economic and Environmental Geology and Prospects for Future Supply dated December 18, 2017).

Vanadium's Growing Importance for Steel Manufacturing and the Energy Sector
Vanadium is growing in importance for key industrial manufacturing sectors, most notably steel and renewable energy. Today, more than 85 percent of the world's vanadium is used in steel manufacturing applications. Its importance to the energy sector is also growing rapidly with more than 10 percent of vanadium production used in energy storage where its substantial cost and performance benefits make it an alternative choice to lithium ion in several areas. Vanadium pentoxide flake prices have risen over the last 2.5 years from under US$3/lb to US$15.7/lb today.

About Cornerstone Metals Inc.
Cornerstone Metals has an option to earn a 100% interest in the Carlin Vanadium Project located in Elko County, 22km by road (14 miles) from the town of Carlin, Nevada. The project is comprised of 72 contiguous unpatented mineral claims totaling 461 hectares (1,140 acres). The Carlin Vanadium Project hosts the Carlin Vanadium Deposit which is flat to shallow dipping and at shallow depths, commonly between 0-60m (0-200 ft) below surface.

ON BEHALF OF CORNERSTONE METALS INC.

per: "Paul Cowley"
CEO & President
(604) 340-7711
pcowley@cornerstonemetals.ca

Technical disclosure in this news release has been reviewed and approved by Paul Cowley, P.Geo., a Qualified Person as defined by National Instrument 43-101, and President and CEO of the Company.

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

Forward-looking information

Certain statements in this news release constitute "forward-looking" statements. These statements relate to future events or the Company's future performance and include theCompany's ability to meet the conditionsrequiredto exercise in full itsoptiontoacquirethe Carlin Vanadium project and with respect to current and planned drill programs, the results of exploration programs,metallurgical test work,and changes in mineral resources.All such statements involve substantial known and unknown risks, uncertainties and other factors which may cause the actual results to vary from those expressed or implied by such forward-looking statements. Forward-looking statements involve significant risks and uncertainties, they should not be read as guarantees of future performance or results, and they will not necessarily be accurate indications of whether or not such results will be achieved. Actual results could differ materially from those anticipated due to a number of factors and risks. Although the forward-looking statements contained in this news release are based upon what management of the Company believes are reasonable assumptions on the date of this news release, the Company cannot assure investors that actual results will be consistent with these forward-looking statements. The forward-looking statements contained in this press release are made as of the date hereof and the Company disclaims any intention or obligation to update or revise any forward-looking statements whether as a result of new information, future events or otherwise, except as required under applicable securities regulations.

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