EXMGF Gunnison Copper Corporation (QB)

Excelsior Mining Corp. (TSX VENTURE: MIN)(OTCQX: EXMGF)(FRANKFURT: 3XS) ("Excelsior") is pleased to announce that the initial hydrological and metallurgical tests on the Gunnison Copper Property are complete. Results are being compiled and will be released within the next several weeks once they are finalized. The Gunnison Property is located within the copper porphyry belt in southern Arizona.

"We look forward to releasing these results in September as they are crucial in developing this deposit as an ISR (in-situ recovery) project," says Stephen Twyerould, President and CEO of Excelsior. "These results will be used to complete a Preliminary Economic Assessment expected later this year."

The hydrological program consisted of drilling two holes within the North Star deposit and included pumping and injecting water to determine the permeability of the mineralization. This new data will supplement the two historical hydrological holes drilled by Magma Copper Corporation in the mid 1990's that demonstrated Gunnison can be mined using ISR techniques.

The metallurgical program consisted of sending samples from two drill holes to Hazen Laboratory in Denver, Colorado for column leach testing. The column leach tests will greatly improve the current understanding of in-situ copper extraction on the Gunnison Property.

Excelsior's exploration work on the Gunnison Property 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.

About Excelsior

Excelsior is an exploration and development company with a copper project located within the copper porphyry belt of Arizona. The Gunnison Copper Project is located close to the required infrastructure and with its in-situ recovery potential, is intended for near-term production. The Excelsior team consists of experienced professionals with proven track records of advancing projects towards production.

Further details about Excelsior can be found at: http://www.excelsiormining.com. Further information about the Gunnison Copper Project can be found in the technical report filed on SEDAR at www.sedar.com entitled: Gunnison Copper Project, Cochise County, Arizona, USA, Mineral Resource of the North Star and South Star Deposits dated June 2010.

ON BEHALF OF THE EXCELSIOR BOARD

Stephen Twyerould, President & CEO

Cautionary Note Regarding Forward-Looking Information

Information set forth in this news release may involve forward-looking statements under applicable securities laws. Forward-looking statements are statements that relate to future, not past, events. In this context, forward-looking statements often address expected future business and financial performance, and often contain words such as "anticipate", "believe", "plan", "estimate", "expect", and "intend", statements that an action or event "may", "might", "could", "should", or "will" be taken or occur, or other similar expressions. All statements, other than statements of historical fact, included herein including, without limitation; statements about the completion of a Preliminary Economic Assessment and the potential to use in-situ recovery methods on the Gunnison Copper Project are forward-looking statements. By their nature, forward-looking statements involve known and unknown risks, uncertainties and other factors which may cause our actual results, performance or achievements, or other future events, to be materially different from any future results, performance or achievements expressed or implied by such forward-looking statements. Such factors include, among others, the following risks: the need for additional financing; operational risks associated with mineral exploration; fluctuations in commodity prices; title matters; environmental liability claims and insurance; reliance on key personnel; the potential for conflicts of interest among certain officers, directors or promoters with certain other projects; the absence of dividends; competition; dilution; the volatility of our common share price and volume and the additional risks identified the management discussion and analysis section of our interim and most recent annual financial statement or other reports and filings with the TSX Venture Exchange and applicable Canadian securities regulations. Forward-looking statements are made based on management's beliefs, estimates and opinions on the date that statements are made and Excelsior undertakes no obligation to update forward-looking statements if these beliefs, estimates and opinions or other circumstances should change, except as required by applicable securities laws. Investors are cautioned against attributing undue certainty to forward-looking statements.

Neither the 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, and no securities regulatory authority has either approved or disapproved of the contents of this release.

Contacts: Excelsior Mining Corp. Investor Relations 604-681-8030 604-681-8039 (FAX) info@excelsiormining.com www.excelsiormining.com