VANCOUVER, BRITISH COLUMBIA--(Marketwire - July 19, 2011) - Excelsior Mining Corp. (TSX VENTURE:MIN)(OTCQX:EXMGF)(FRANKFURT:3XS) ("Excelsior") is pleased to announce a significant increase to the mineral resource estimate at the North Star Deposit. The oxide copper (Cu) mineral resource has increased from 2.86 billion pounds of Cu (404 million tons at 0.35% Cu) in the inferred category to an indicated copper resource of 3.21 billion pounds and an additional inferred resource of 0.88 billion pounds Cu (refer to table below for tonnage and grade details). The North Star Deposit is part of the Gunnison Copper Property located within the copper porphyry belt in southern Arizona.

The South Star Deposit was not drilled this year and remains unchanged with an inferred resource of 0.38 billion pounds of oxide Cu (62 million tons at 0.30% Cu at a cut-off of 0.1% Cu – see news release dated November 2, 2010).

"We are extremely excited about our updated resource as we not only moved the majority of the oxide resource from the inferred to the indicated category, but we also significantly increased the global resource," says Stephen Twyerould, President and CEO of Excelsior. "As our plan is to mine Gunnison using in-situ recovery mining techniques, our focus is the oxide component of the property, although the mixed and sulphide components have also significantly increased. This upgraded resource represents the first of several milestones that Excelsior aims to achieve over the coming months."

Category Short Tons (million) Total Copper % Tons of Cu (million) Pounds of Cu (billion)
Indicated 511 0.31 1.60 3.21
Inferred 159 0.28 0.44 0.88
Category Short Tons (million) Total Copper % Tons of Cu (million) Pounds of Cu (billion)
Indicated 237 0.44 1.05 2.10
Inferred 50 0.47 0.24 0.47
Category Short Tons (million) Total Copper % Tons of Cu (million) Pounds of Cu (billion)
Indicated 554 0.32 1.76 3.52
Inferred 200 0.30 0.61 1.22
Note: 0.1% cut-off for Oxide component and 0.3% cut-off for Mixed and Sulphide components

Resource Estimate Details

The mineral resource estimate for the North Star Deposit is based on results from 109 drill holes totalling 141,252 feet (ft) and is effective as of June 20th, 2011. Mr. Herb Welhener, (MMSA-QP) with the independent firm, Independent Mining Consultant of Tucson, Arizona is a Qualified Person as defined by NI 43-101 and is responsible for this mineral resource estimate. He has verified, reviewed and approved the technical disclosure contained in this news release and underlying sampling, analytical and test data. The estimate is classified as an indicated or inferred mineral resource, consistent with the CIM definitions referred to in NI 43-101. This NI 43-101 compliant estimate will be filed in a Technical Report on SEDAR within 45 days of this news release. Excelsior is not aware of any environmental, permitting, legal, title, taxation, socio-political, marketing or other issues which may materially affect its estimate of mineral resources.

The mineral resource estimate is contained within a block model of the North Star deposit covering a surface area of 3.30 square miles and to a maximum depth of 2,575 feet below the topographic surface. The major geologic formations and oxidization types are incorporated into the block model based on the drill hole intercept data. The copper grades are estimated using an ordinary kriging estimation technique from 25 ft drill hole composite data. The grade estimate uses a 700 ft circular by 50 ft search distance dipping 30 degrees east to parallel the general dip of the sedimentary units. The 700 ft distance is 70% of the variogram range and the indicated category requires three or more holes within the search distance. All other blocks which received a grade estimate are classified as inferred. No copper grades are estimated in to the overburden or the non-sedimentary rock units.

All samples are prepared from manually split half-core sections on site in Arizona. Split drill core samples are then sent to 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.

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:


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 future exploration on and the development of the Gunnison Project and the ability to mine Gunnison using in-situ recovery mining techniques 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 Alderon 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.

Cautionary Note Concerning Reserve and Resource Estimates

This press release uses the terms "reserves", "resources", "proven reserves", "probable reserves", "measured resources", "indicated resources" and "inferred resources". United States investors are advised that, while such terms are recognized and required by Canadian securities laws, the United States Securities and Exchange Commission (the "SEC") does not recognize them. Under United States standards, mineralization may not be classified as a "reserve" unless the determination has been made that the mineralization could be economically and legally produced or extracted at the time the reserve determination is made. Mineral resources that are not mineral reserves do not have demonstrated economic viability. United States investors are cautioned not to assume that all or any part of measured or indicated resources will ever be converted into reserves. Inferred Resources are in addition to Measured and Indicated Resources. Further, inferred resources have a great amount of uncertainty as to their existence and as to whether they can be mined legally or economically. It cannot be assumed that all or any part of the inferred resources will ever be upgraded to a higher category. Therefore, United States investors are also cautioned not to assume that all or any part of the inferred resources exist, or that they can be mined legally or economically. Disclosure of "contained ounces" is permitted disclosure under Canadian regulations, however, the SEC normally only permits issuers to report "resources" as in place tonnage and grade without reference to unit measures. Accordingly, information concerning descriptions of mineralization and resources contained in this release may not be comparable to information made public by United States companies subject to the reporting and disclosure requirements of the SEC.

National Instrument 43-101 Standards of Disclosure for Mineral Projects ("NI 43-101") is a rule developed by the Canadian Securities Administrators, which established standards for all public disclosure an issuer makes of scientific and technical information concerning mineral projects. Unless otherwise indicated, all reserve and resource estimates referred to in this press release or released by the Company in the future have been or will be prepared in accordance with NI 43-101 and the Canadian Institute of Mining, Metallurgy and Petroleum Classification System. The requirements of NI 43-101 are not the same as those of the SEC and any reserves reported by the Company in compliance with NI 43-101 may not qualify as reserves under the SEC's standards.

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.

Contact Information:

Excelsior Mining Corp.
Investor Relations
604-681-8039 (FAX)