McEwen Mining Announces Resource Update at the Los Azules

McEwen Mining Announces Resource Update at the Los Azules Copper
Project in Argentina 
TORONTO, ONTARIO -- (Marketwire) -- 06/28/12 -- McEwen Mining Inc.
(NYSE:MUX)(TSX:MUX) is pleased to announce an updated resource
estimate for its 100% owned Los Azules Copper Project in San Juan
Province, Argentina. Drilling has increased both the level of
confidence associated with the mineralization and the size of the
resource. The estimated contained copper metal in the Indicated
Resource category has increased by 109% to 4.6 billion lbs. and the
estimated contained copper metal in the Inferred Resource category
increased by 4% to 10.8 billion lbs. 


 
                Los Azules Copper Project Resource Highlights               
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                   June 2010                  June 2012                     
               Resource Estimate       Resource Estimate Update             
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Cut-off      Tonnage    Cu              Tonnage    Cu              % Change 
Grade       (million Grade     Cu lbs  (million Grade     Cu lbs (contained 
(Cu%)        tonnes)   (%) (billions)   tonnes)   (%) (billions)        Cu) 
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Indicated Resource                                                          
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0.35             137  0.73        2.2       323  0.65        4.6       +109%
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Inferred Resource                                                           
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0.35             900  0.52       10.4       948  0.52       10.8         +4%
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(i)Details for gold and silver resources are included in Table 1.           

 
"Los Azules is one of the world's largest undeveloped copper
deposits. We are looking forward to commencing our most ambitious
drill program this November. This deposit appears to have good
potential to expand in size," stated Rob McEwen, Chairman and Chief
Owner. 
The objective of the Company's exploration program since the last
resource update in June 2010 was to 1) test the expansion potential;
and 2) continue to infill portions of the deposit. Drilling
successfully expanded the overall size of the Inferred resource while
maintaining the same grade. In addition, 186 million tonnes of
Inferred resource was converted to the Indicated category. The grade
of the Indicated resource decreased since the mineralization that was
being upgraded was of a lower grade. Los Azules has a significant
high grade core (using a cut-off grade of 0.70% copper) totaling 112
million tonnes at an average grade of 0.89% copper in the Indicated
category and 119 million tonnes at an average grade of 0.86% copper
in the Inferred category. 
Despite limited drilling, approximately 8,100 meters from January
2011 to April 2012, the expansion of the resource was successfully
achieved by drilling step-out holes primarily to the southwest of the
known deposit which confirmed that mineralization continues laterally
and at depth. 
McEwen Mining has signed a contract with Major Drilling to provide
four core drills and one reverse-circulation drill for the 2012-13
drill season. These core rigs are considerably more powerful than the
ones used during the 2011-12 season and the Company believes this
will increase the likelihood of reaching target depths (+700 meters),
where high-grade copper mineralization has been encountered. McEwen
Mining anticipates starting the upcoming drill season in November and
plans a total of 15,000 meters of drilling. 
About Los Azules 
Los Azules is a large copper porphyry system located in western San
Juan Province within a belt of porphyry copper deposits that
straddles the Chilean/Argentine border. This belt contains some of
the world's largest copper deposits, including Codelco's El Teniente
and Andina mines, Anglo American's Los Bronces mine, Antofagasta
PLC's Los Pelambres mine and Xstrata's El Pachon project, among
others. 
A portion of the Los Azules Copper Project is subject to litigation
in the Courts of British Columbia (please see Exhibit 1).
Shareholders and other interested parties are encouraged to review
our most recent quarterly filings for detailed information. The trial
is set to commence in November 2012 and last for approximately six
weeks.  
Table 1. Los Azules Mineral Resource Estimate 
In order to exhibit reasonable prospects for economic viability, the
mineral resource estimate has been contained within a conceptual open
pit shell generated using general technical and economic parameters
that are defined at the end of this news release. The base case
cut-off grade of 0.35% Cu is highlighted in the table.  


 
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                                             Au                Ag           
                                          Grade             Grade           
Cut-off        Tonnage     Cu            (grams            (grams           
 Grade        (million  Grade     Cu lbs    per      Au Oz    per      Ag Oz
(Cu%)          tonnes)    (%) (billions) tonne) (millions) tonne) (millions)
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Indicated Resource                                                          
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0.15               415   0.57        5.2   0.06       0.84    1.8       23.9
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0.20               401   0.58        5.1   0.06       0.82    1.8       23.2
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0.25               378   0.60        5.0   0.06       0.79    1.8       21.9
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0.30               350   0.63        4.8   0.07       0.75    1.8       20.5
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0.35               323   0.65        4.6   0.07       0.71    1.8       19.1
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0.40               295   0.68        4.4   0.07       0.66    1.9       17.7
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0.45               268   0.70        4.2   0.07       0.61    1.9       16.3
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0.50               238   0.73        3.8   0.07       0.55    1.9       14.7
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0.55               205   0.77        3.5   0.07       0.48    1.9       12.8
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0.60               174   0.80        3.1   0.08       0.42    1.9       10.9
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0.65               142   0.84        2.6   0.08       0.35    1.9        8.8
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0.70               112   0.89        2.2   0.08       0.28    1.9        6.9
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Inferred Resource                                                           
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0.15             2,486   0.35       19.1   0.05       3.67    1.6      128.7
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0.20             2,116   0.38       17.7   0.05       3.29    1.6      111.6
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0.25             1,660   0.42       15.4   0.05       2.77    1.7       90.7
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0.30             1,256   0.47       13.0   0.06       2.24    1.8       71.9
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0.35               948   0.52       10.8   0.06       1.79    1.8       56.1
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0.40               708   0.57        8.8   0.06       1.40    1.9       43.5
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0.45               523   0.62        7.1   0.06       1.08    2.0       33.3
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0.50               391   0.67        5.7   0.07       0.84    2.0       25.6
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0.55               285   0.72        4.5   0.07       0.63    2.1       19.1
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0.60               211   0.77        3.6   0.07       0.48    2.1       14.3
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0.65               158   0.82        2.8   0.07       0.37    2.2       11.0
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0.70               119   0.86        2.3   0.07       0.28    2.2        8.5
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(i)   "Tonnes" is stated in metric and is equivalent to 2205 lbs.           
(ii)  Estimated contained metal values may be subject to rounding errors.   

 
To view the figure associated with this release, please visit the
following link: http://media3.marketwire.com/docs/mux0628fig1.pdf. 
Details on the parameters of the resource estimate are as follows: 


 
--  The resource estimation was based on data from 163 drill holes
    comprising a total length of 43,645 meters of drilling completed to the
    end of April 2012. 
 
--  There were a total of 20,557 individual samples selected for analysis.
    The samples were collected and analyzed in accordance with industry
    standards. Splits from the drill core samples were submitted to either
    Alex Stewart in Mendoza or ALS Chemex or ACME in Santiago, Chile for
    fire assay and ICP analysis. Accuracy of results is tested through the
    systematic inclusion of standards, blanks and check assays. 
 
--  The June 2012 mineral resource estimate for the Los Azules Copper
    Project was prepared under the direction of Robert Sim P.Geo. of SIM
    Geological Inc. The mineral resource estimate uses drill hole sample
    assay results and the interpretation of a geologic model that relates to
    the spatial distribution of copper, gold and silver in the deposit.
    Interpolation characteristics were defined based on the geology, drill
    hole spacing and geostatistical analysis of the data. Block grade
    estimates were done using Ordinary Kriging (OK) with a nominal block
    size measuring 20 meters long, 20 meters wide and 15 meters high.
    Resources are classified according to their proximity to sample data
    locations and are reported, as required under NI 43-101, according to
    the CIM standards for Mineral Resources and Reserves.   
 
--  As required under NI 43-101, reasonable prospects for economic viability
    of the mineral resources have been exhibited by the application of a
    resource limiting pit shell built about copper grades in the model using
    a projected metal price of US$2.50 per lb. Cu, mining costs of US$1.00
    per tonne, milling and G&A costs of US$4.25 per tonne, 100% recoveries
    and an average pit slope of 34 degrees. 
 
--  Mineral resources, which are not mineral reserves, do not have
    demonstrated economic viability. 
 
--  The quantity and grade of reported Inferred resources are uncertain in
    nature and there has been insufficient exploration to classify these
    inferred resources as Indicated or Measured, and it is uncertain if
    further exploration will result in upgrading them to an Indicated or
    Measured category. 

 
About McEwen Mining (www.mcewenmining.com)  
The goal of McEwen Mining is to qualify for inclusion in the S&P 500
by 2015 by creating a high growth, low-cost, mid-tier gold producer
focused in the Americas. McEwen Mining's principal assets consist of
the San Jose Mine in Santa Cruz, Argentina (49% interest); the El
Gallo Complex in Sinaloa, Mexico; the Gold Bar Project in Nevada, US;
the Los Azules Project in San Juan, Argentina and a large portfolio
of exploration properties in Argentina, Nevada and Mexico. 
McEwen Mining has 267,919,384 shares issued and outstanding. Rob
McEwen, Chairman, President and CEO, owns 25% of the shares of the
Company. As of March 31, 2012, McEwen Mining had cash and liquid
assets of US$66.7 million, comprised of cash of US$41.1 million,
silver and gold bullion at market value of US$21.4 million,
short-term investments of US$3.1 million and marketable securities of
US$1.1 million. The Company continues to hold a significant portion
of its treasury in bullion with the belief that prices will continue
to rise.  
Technical Information: 
James K. Duff, Senior Consultant to the Company and a Registered
Member in good standing of the Society for Mining, Metallurgy and
Exploration, who is a Qualified Person as defined by National
Instrument 43-101 ("NI 43-101") has reviewed and approved the
contents of this news release. Bruce Davis, PhD, FAusIMM, who is a
Qualified Person as defined by NI 43-101 and responsible for the
quality control for the assaying of the Los Azules drill core has
reviewed the assay quality control information. All samples were
collected in accordance with industry standards. Splits from the
drill core samples were submitted to the ACME sample preparation
laboratory in Mendoza, Argentina, and then transferred to ACME's
laboratory in Santiago, Chile for fire assay and ICP analysis.
Accuracy of results is tested through the systematic inclusion of
standards, blanks and check assays. The mineral resource estimate
referenced in this press release was prepared in June 2012 by Robert
Sim, P.Geo. and Bruce Davis, PhD, FAusIMM, both independent Qualified
Persons as defined by NI 43-101. 
For further information in respect of the Los Azules Project please
refer to the technical report entitled "Canadian National Instrument
43-101 Updated Preliminary Assessment, Los Azules Project, San Juan
Province, Argentina" dated December 16, 2010, prepared by Kathleen
Altman, Robert Sim, Bruce Davis, William L. Rose, Scott Elfen, and
Richard Jemielita, each of whom is an independent Qualified Person as
defined by NI 43-101. This report is available under Minera Andes
Inc.'s (acquired by McEwen Mining) profile on SEDAR (www.sedar.com).
There can be no assurance that the capital cost estimates in this
report remain accurate; given the inflationary pressure in the mining
industry and in Argentina, these capital costs, if calculated as of
today's date, are likely to increase significantly. 
The Los Azules PEA and the resource estimates and other information
contained herein do not constitute a feasibility or pre-feasibility
study and contain no mineral reserves within the meaning of NI 43-101
or SEC Industry Guide 7. The mineral resource figures referred to in
this press release and the Los Azules PEA are estimates and therefore
insufficient to allow meaningful application of the technical and
economic parameters to enable an evaluation of technical or economic
viability and no assurances can be given that the indicated levels of
gold and silver will be produced. Such estimates are expressions of
judgment based on knowledge, mining experience, analysis of drilling
results and industry practices. Valid estimates made at a given time
may significantly change when new information becomes available.
While the Company believes that the resource estimates included in
this press release and the Los Azules PEA are well established, by
their nature, resource estimates are imprecise and depend, to a
certain extent, upon statistical inferences which may ultimately
prove unreliable. If such estimates are inaccurate or are reduced in
the future, this could have a material adverse impact on the Company.
In addition, the Los Azules PEA and this news release includes
inferred resources that are too speculative geologically to have
economic considerations applied to them that would enable them to be
categorized as mineral reserves, and there is no certainty that the
Los Azules PEA will be realized. 
Cautionary Note to U.S. Investors: 
McEwen Mining reports its resource estimates in accordance with
standards of the Canadian Institute of Mining, Metallurgy and
Petroleum referred to NI 43-101. These standards are different from
the standards generally permitted in reports filed with the SEC.
Under NI 43-101, McEwen Mining reports measured, indicated and
inferred resources, measurements which are generally not permitted in
filings made with the SEC. According to Canadian NI 43-101 criteria,
the estimation of measured resources and indicated resources involve
greater uncertainty as to their economic feasibility than the
estimation of proven and probable reserves. Under SEC Industry Guide
7 criteria, measured, indicated and inferred resources are considered
Mineralized Material. The SEC considers that in addition to greater
uncertainty as to the economic feasibility of Mineralized Material
compared to proven and probable reserves, there is also greater
uncertainty as to the existence of Mineralized Material. U.S.
investors are cautioned not to assume that measured or indicated
resources will be converted into economically mineable reserves. The
estimation of inferred resources involves far greater uncertainty as
to their existence and economic viability than the estimation of
other categories of resources. 
Caution Concerning Forward-Looking Statements 
This press release contains certain forward-looking statements and
information, including "forward- looking statements" within the
meaning of the Private Securities Litigation Reform Act of 1995. The
forward-looking statements and information expressed, as at the date
of this press release, McEwen Mining Inc.'s (the "Company")
estimates, forecasts, projections, expectations or beliefs as to
future events and results. Forward-looking statements and information
are necessarily based upon a number of estimates and assumptions
that, while considered reasonable by management, are inherently
subject to significant business, economic and competitive
uncertainties, risks and contingencies, and there can be no assurance
that such statements and information will prove to be accurate.
Therefore, actual results and future events could differ materially
from those anticipated in such statements and information. Risks and
uncertainties that could cause results or future events to differ
materially from current expectations expressed or implied by the
forward-looking statements and information include, but are not
limited to, risks related to business integration as a result of the
business combination between US Gold and Minera Andes, factors
associated with fluctuations in the market price of precious metals,
mining industry risks, political, economic, social and security risks
associated with foreign operations, risks associated with the
construction of mining operations and commencement of production and
the projected costs thereof, risks related to litigation including
specifically but not limited to ongoing litigation with respect to
the Los Azules property which if resolved adversely to the Company,
would materially affect the Company's ability to develop the Los
Azules Project, property title, the state of the capital markets,
environmental risks and hazards, uncertainty as to calculation of
mineral resources and reserves and other risks. Readers should not
place undue reliance on forward-looking statements or information
included herein, which speak only as of the date hereof. The Company
undertakes no obligation to reissue or update forward-looking
statements or information as a result of new information or events
after the date hereof except as may be required by law. See McEwen
Mining's Annual Report on Form 10-K for the fiscal year ended
December 31, 2011 and other filings with the Securities and Exchange
Commission, under the caption "Risk Factors", for additional
information on risks, uncertainties and other factors relating to the
forward-looking statements and information regarding the Company. All
forward-looking statements and information made in this news release
are qualified by this cautionary statement.  
The NYSE and TSX have not reviewed and do not accept responsibility
for the adequacy or accuracy of the contents of this news release,
which has been prepared by management of McEwen Mining Inc. 
Contacts:
McEwen Mining Inc.
Jenya Meshcheryakova
Investor Relations
(647) 258-0395 ext 410 or Toll Free: (866) 441-0690
(647) 258-0408 (FAX) 
McEwen Mining Inc.
Mailing Address
181 Bay Street Suite 4750
Toronto, ON M5J 2T3
PO Box 792
info@mcewenmining.com 
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