Mr. Stephen Twyerould reports

EXCELSIOR MINING ANNOUNCES ASSAY RESULTS FROM JCM STAGE 1 DRILLING WITH NUTON, A RIO TINTO VENTURE

Excelsior Mining Corp. has released assay results at the Johnson camp mine (JCM) from the Stage 1 drilling with Nuton LLC, a Rio Tinto venture. The program consists of drilling approximately 6,000 feet of PQ core, primarily for the purposes of further metallurgical evaluation. The samples from the drill program will be processed for mineralogy and tested using the Nuton(TM) process. The program is being funded by Nuton and carried out by Excelsior in connection with the previously announced Option to JV Agreement.

"The initial drill results from the bottom of the Burro pit are high-grade, averaging around 1% copper. These grades are in-line with expectations in this area, which is why we remain excited about the prospects of mining and leaching this predominantly sulfide copper mineralization in partnership with Nuton," comments Roland Goodgame, Senior Vice President Business Development.

A total of 11 of the 13 planned holes have been drilled using diamond drill rigs to generate PQ sized core, with 5 of the drilled holes still awaiting assays. The program is divided into two phases. Phase 1 holes (designated PH1) were drilled from the bottom of the Burro open pit towards the east and northeast and were declined at about 35 degrees. These holes were designed to drill approximately parallel to the dip of the easterly dipping mineralized horizon. The purpose of this drilling is to collect a relatively large volume of representative material for metallurgical testing. Assay results are included in Table 1 below.

The PH1 series holes were drilled down the dip or at a low angle to the dip of the mineralized horizons and as such a true width is difficult to determine. The mineralized horizon in this area is typically 60 to 160 feet in true width, however the grades in these holes may not be applicable to that entire true width. This mineralization is exposed in the bottom of the Burro pit and is one of the main targets for the potential re-start of the Burro pit. The Phase one holes started in high-grade mineralization and all holes finished in mineralization indicating the mineralization continues down dip. Approximately the first half of the holes in Table 1 were sulfide dominant (pyrite and chalcopyrite), whilst the second half included some transitional and oxide copper mineralization.

Unlike the Phase 1 holes, the Phase 2 holes were drilled from high on the eastern wall of the open pit and were designed to intersect the mineralized horizons below at a high angle to bedding. No phase 2 assay results are available yet.

All samples are prepared from manually split or sawn PQ core sections on site in Arizona. Split drill core samples are then sent to independent laboratory Skyline Assayers & Laboratories in Tucson, Arizona for Total Copper and Sequential Copper analyses. Standards, blanks, and duplicate assays are included at regular intervals in each sample batch submitted from the field as part of an ongoing Quality Assurance/Quality Control Program. Pulps and sample rejects are stored by Excelsior for future reference.

About The Johnson Camp mine

The Johnson Camp Mine ("JCM") has historically been an open pit, heap leach operation since Cyprus Minerals opened the property in the 1970's. The operation includes two open pits, a two-stage crushing-agglomerating circuit, a fully functioning SX-EW plant capable of producing 25 million pounds of cathode copper per year, a complete set of PLS and raffinate ponds, and full infrastructure (ancillary facilities, access, power, water, and communications).

An updated Preliminary Economic Assessment (PEA) incorporating sulfide leaching technology was announced February 22nd 2023. Mining of JCM would be by traditional open pit. The highlights of the PEA financial model, using a copper price of $3.75/lb, shows an after-tax NPV of US$180 million (7.5% discount rate), and an after-tax IRR of 30.4%. The results are tabulated below.

The PEA is preliminary in nature and includes inferred mineral resources that are considered too speculative geologically to have the economic considerations applied to them that would enable them to be categorized as mineral reserves. There is no certainty that the conclusions reached in the PEA will be realized. Mineral resources that are not mineral reserves do not have demonstrated economic viability.

QUALIFIED PERSON

Excelsior's exploration work on the Johnson Camp mine is supervised by Stephen Twyerould, Fellow of AUSIMM, President and CEO of Excelsior and a Qualified Person as defined by NI 43-101. Mr. Twyerould has reviewed and is responsible for the technical information contained in this news release. Mr. Twyerould has verified the data disclosed in this news release, including sampling, analytical and test data underlying the information disclosed in this news release. Mr. Twyerould has verified that the results were accurate from the official assay certificates provided to Excelsior.

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.

About Nuton

Nuton is an innovative new venture that aims to help grow Rio Tinto's copper business. At the core of Nuton is a portfolio of proprietary copper leach related technologies and capability - a product of almost 30 years of research and development. The Nuton technologies offer the potential to economically unlock known low-grade copper sulfide resources, copper bearing waste and tailings, and achieve higher copper recoveries on oxide and transitional material, allowing for a significantly increased copper production outcome. One of the key differentiators of Nuton is the potential to deliver leading environmental performance, including more efficient water usage, lower carbon emissions, and the ability to reclaim mine sites by reprocessing mine waste.

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