Rain City (RAIN) Reports Independent Report Confirms Successful Lithium Extraction from the Marcellus Shale in Pennsylvania

Calgary, Alberta--(Newsfile Corp. - June 26, 2025) - Rain City Resources (CSE: RAIN) (the "Company" or "Rain") and Avonlea Lithium Corporation ("ALC") announce the successful completion of a pilot test of the proprietary ACCELi technology using lithium-rich brine sourced from fracking in the Marcellus Shale, Pennsylvania. Rain has an option to earn a 100% interest in ALC.

Brine and solids analyses from the pilot test were sent to Montrose Environmental Group ("Montrose"), an independent environmental testing services in Calgary. A draft report confirming that the ACCELi (Accelerated Chemical Cavitation Extraction of Lithium) process performed as intended, yielding lithium phosphate solids with a purity of 94.2%. The third and final test run achieved a lithium recovery rate of 69.3%. The average concentration of lithium taken from the source tank across the three batch runs was 243mg/l.

Each of the three test runs showed continuous improvement, with the equipment operating as designed. The ACCELi process selectively extracted lithium, barium, strontium, magnesium, and calcium based on their solubility, and precise chemical data, efficiently extracting these as saleable by-products.

Accurate brine analyses were ultimately sourced for the last test from Isobrine Ltd. in Edmonton and they provided the necessary data to optimize dosing and improve ion removal before the lithium extraction stage. Having this accurate chemical data saw a saleable calcium carbonate produced at > 98% purity along with lithium phosphate yielding a purity of 94.2%.

The final lithium phosphate product produced a purity of 94.2% with a recovery rate of 69.3%. This was in line with our expectation when considering, amongst other things input concentration, time on site and an initial delayed receipt of accurate chemical analytical results. Future improvements in purity and recovery are expected by ensuring accurate chemical analyses are readily available before each step of the process. We believe that the remaining lithium present in the brine after this final process can be recovered using additional stages or by being paired with an identified complimentary recovery technique.

Commenting on the pilot plant and the Montrose independent analysis, Dr. Ian Hutcheon, Director of Rain and Professor Emeritus of Geochemistry at the University of Calgary said, "The performance of the ACCELi system in this pilot test provides a significant step forward to the development of a commercial lithium extraction facility in Pennsylvania. The future potential of ACCELi in Chile and Argentina, where scarce water resources require a process that has very low or no additional freshwater requirements, has been clearly demonstrated in our pilot test which is of particular importance as we move towards developing our presence in South America."

Benjamin Hill, CEO of Rain commented, "From executing an earn in agreement to successfully concluding our first in-field pilot plant test within a year Rain and Avonlea join the few DLE companies that have tested their technology on real brines in-situ. We believe ACCELi to be the only DLE technology that can deal with the variable brine chemistry characteristics (in this case from the Marcellus Shale) in real time having successfully processed brine sourced from different areas with different compositions during the Pennsylvania field test.

Having had our technology and results scrutinized and validated by industry experts we maintain our high levels of comfort in the ACCELi process and patented Cavitek technology. We are obviously very pleased to see Montrose corroborate our findings and that even with a lower concentration of lithium in the brine we were ultimately able to achieve both a high recovery rate and purity of lithium phosphate along with immediately saleable by-products from the process.

Following the completion of the pilot test at Kendra II's Springville WMG 123 Facility, Kendra II have agreed in principle to enter into an arrangement to jointly work to commercially develop ACCELi Cavitek plants at their facilities across Pennsylvania".

The Company has relocated its head office from Vancouver, B.C. to Calgary, Alberta in order to be more closely located to its partner in the ACCELi Cavitek technology. The office address effective July 1, 2025 is Suite 145 - 251 Midpark Blvd S.E., Calgary, Alberta T2X 1S3. The Company's telephone number will concurrently change to +1-403-693-8004.

About Us

Rain is an integrated critical mineral technology and project development company committed to solving the environmental, social, and economic issues associated with extracting lithium and other critical minerals from brine.

FOR FURTHER INFORMATION CONTACT:

Benjamin Hill 
Chief Executive 

David Shaw
Officer Chairperson

Cautionary Statement Regarding Forward-Looking Information

This news release may include certain "forward-looking statements" under applicable Canadian securities legislation. There can be no assurance that such statements will prove to be accurate, as actual results and future events could differ materially from those anticipated in such statements. Accordingly, readers should not place undue reliance on forward-looking statements. Rain 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 by law. There can be no assurance that proposed operations will be successful or that the anticipated financial, economic or strategic benefits will be realized.

Neither the Canadian Securities Exchange nor its Regulation Service Provider (as the term is defined in the policies of the Canadian Securities Exchange) accepts responsibility for the adequacy of accuracy of this news release.

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