Excelsior Mining Announces Well Stimulation Modelling Results for the Gunnison Copper Project

Phoenix, Arizona--(Newsfile Corp. - October 18, 2022) - Excelsior Mining Corp. (TSX: MIN) (FSE: 3XS) (OTCQX: EXMGF) ("Excelsior" or the "Company") is pleased to announce the results of Well Stimulation modelling for the Gunnison Copper Project, located in Cochise County, southeastern Arizona.

Well stimulation has the potential to fundamentally change the performance of the wellfield, reduce the need for raffinate neutralization or change the design criteria for the neutralization plant.

Well stimulation is primarily intended to inflate (open-up) the pre-existing mineralized facture network in the wellfield to help gas bubbles (CO₂) escape. It can enlarge pre-existing channels and flow paths, increase pore space and make it possible for solution to move more readily from injection to recovery well. Doing so would improve connectivity between these wells, improve flow rates and copper production. To this end Excelsior commissioned a leading engineering and environmental consulting firm to undertake well stimulation modelling on a selection of wells within the current wellfield. The model showed that well stimulation successfully inflated pre-existing fractures over significant volumes around the central well within the 5-spot pattern.

Based on the successful modelling results, Excelsior is excited to proceed to field trials in 2023, subject to EPA approval. The EPA is currently processing Excelsior's permit amendment to allow well stimulation, which is expected to be approved in Q1 2023. Field trials are planned shortly thereafter.

Robert Winton commented: "This could have a material positive effect on Excelsior's operations. Successful field trials could lead to rapid commercialization of the technique to the point where it becomes part of our regular well maintenance plan."

Summary:

• Well stimulation is expected to be successful at increasing the natural fracture permeability for significant volumes within the wellfield
• Immediate permeability enhancement is expected to be one to two orders of magnitude
• Although modelling results are very encouraging, field trials may not perform as modelled and operational conditions may affect the final results.
• Risk factors that will be evaluated further as part of the field trials.

More information including graphical representations of the modelling can be found on Excelsior's website at Excelsior Mining Corp - Well Stimulation.

Excelsior also announces that Stephen Twyerould President & CEO, and Robert Winton SVP and General Manager, will be presenting during a live-video webinar with a Q&A on Thursday, October 27th at 4:05 PM Eastern Time. The event will be hosted by Amvest Capital. Those wishing to participate in the video-webinar can do so by Registering Here.

QUALIFIED PERSON

The scientific and technical information contained in this news release has been reviewed and approved by Roland Goodgame, Member of the Australian Institute of Geoscientists MAIG, SVP Business Development of Excelsior, and a Qualified Person as defined by National Instrument 43-101. Mr. Goodgame has reviewed and approved the scientific and technical information contained in this news release and underlying data.

ABOUT EXCELSIOR MINING

Excelsior "The Copper Solution Company" is a mineral exploration and production company that owns and operates the Gunnison Copper Project in Cochise County, Arizona. The project is a low cost, environmentally friendly in-situ recovery copper extraction project that is permitted to 125 million pounds per year of copper cathode production. Excelsior also owns the past producing Johnson Camp Mine and a portfolio of exploration projects, including the Peabody Sill and the Strong and Harris deposits.

For more information on Excelsior, please visit our website at www.excelsiormining.com.

For further information regarding this press release, please contact:

Excelsior Mining Corp.
Concord Place, Suite 300, 2999 North 44^th Street, Phoenix, AZ, 85018.

Shawn Westcott
T: 604.365.6681
E: info@excelsiormining.com
www.excelsiormining.com

Cautionary Note Regarding Forward-Looking Information

This news release contains "forward-looking information" concerning anticipated developments and events that may occur in the future. Forward looking information contained in this news release includes, but is not limited to, statements with respect to: (i) the intention to mine Johnson Camp and future production therefrom; (ii) permitting timelines; (iii) the development timeline to mine Johnson Camp; and (iv) details of future operational plans.

In certain cases, forward-looking information can be identified by the use of words such as "plans", "expects" or "does not expect", "budget", "scheduled", "estimates", "forecasts", "intends", "anticipates" or "does not anticipate", or "believes", or variations of such words and phrases or state that certain actions, events or results "may", "could", "would", "might", "occur" or "be achieved" suggesting future outcomes, or other expectations, beliefs, plans, objectives, assumptions, intentions or statements about future events or performance. Forward-looking information contained in this news release is based on certain factors and assumptions regarding, among other things, the availability of financing to implement the Company's operational plans, the estimation of mineral resources and mineral reserves, the realization of resource and reserve estimates, expectations and anticipated impact of the COVID-19 outbreak, copper and other metal prices, the timing and amount of future development expenditures, the estimation of initial and sustaining capital requirements, the estimation of labour and operating costs (including the price of acid), the availability of labour, material and acid supply, receipt of and compliance with necessary regulatory approvals and permits, the estimation of insurance coverage, and assumptions with respect to currency fluctuations, environmental risks, title disputes or claims, and other similar matters. While the Company considers these assumptions to be reasonable based on information currently available to it, they may prove to be incorrect.

Forward looking information involves known and unknown risks, uncertainties and other factors which may cause the actual results, performance or achievements of the Company to be materially different from any future results, performance or achievements expressed or implied by the forward-looking information. Such factors include risks inherent in the construction and operation of mineral deposits, including risks relating to changes in project parameters as plans continue to be redefined including the possibility that mining operations may not be sustained at the Gunnison Copper Project, risks that field trials of well stimulation may show the fracture system does not form as modelled and more trials are needed to perfect the technique, the risk that field trials of well stimulation do not perform as anticipated, the risk that despite the large volume stimulated (inflated) by well stimulation, acid operating conditions may still result in excessive CO₂ build up, risks relating to variations in mineral resources and reserves, grade or recovery rates, risks relating to the ability to access infrastructure, risks relating to changes in copper and other commodity prices and the worldwide demand for and supply of copper and related products, risks related to increased competition in the market for copper and related products, risks related to current global financial conditions, risks related to current global financial conditions and the impact of COVID-19 on the Company's business, uncertainties inherent in the estimation of mineral resources, access and supply risks, risks related to the ability to access acid supply on commercially reasonable terms, reliance on key personnel, operational risks inherent in the conduct of mining activities, including the risk of accidents, labour disputes, increases in capital and operating costs and the risk of delays or increased costs that might be encountered during the construction or mining process, regulatory risks including the risk that permits may not be obtained in a timely fashion or at all, financing, capitalization and liquidity risks, risks related to disputes concerning property titles and interests, environmental risks and the additional risks identified in the "Risk Factors" section of the Company's reports and filings with applicable Canadian securities regulators.

Although the Company has attempted to identify important factors that could cause actual actions, events or results to differ materially from those described in forward-looking information, there may be other factors that cause actions, events or results not to be as anticipated, estimated or intended. Accordingly, readers should not place undue reliance on forward-looking information. The forward-looking information is made as of the date of this news release. Except as required by applicable securities laws, the Company does not undertake any obligation to publicly update or revise any forward-looking information.

To view the source version of this press release, please visit https://www.newsfilecorp.com/release/140904