McEwen Mining Los Azules Metallurgical Update

McEwen Mining Los Azules Metallurgical Update 
Alternative Process Methods Demonstrate Potential for Improved
Economic Returns 
TORONTO, ONTARIO -- (Marketwire) -- 03/13/13 -- McEwen Mining Inc.
(NYSE:MUX)(TSX:MUX) is pleased to announce new metallurgical studies
that confirmed preliminary work and tested alternative process
methods at its 100% owned Los Azules Copper Project in San Juan
Province, Argentina. The work was performed by Plenge Metallurgical
Laboratory in Lima, Peru and supervised by Samuel Engineering of
Denver, Colorado. The tests produced positive results in the three
areas discussed below, all of which should improve the economic
returns associated with the project by reducing operating and capital
costs, increasing the amount of material available for processing,
and reducing export taxes. 
1) Flotation optimization 
Test results confirm that a significantly coarser grind size of 175
micrometres can be used on Los Azules mineralized material versus the
125 micrometres used in past testing. This will reduce milling costs
and should not negatively impact copper recoveries which have been
estimated at approximately 93%. 
2) Pressure oxidation on flotation concentrates 
A Preliminary Economic Assessment ("PEA") was completed on the Los
Azules project in 2010.  It contemplated that a copper concentrate
would be produced on site and then shipped to a port on the Pacific
coast via a pipeline through Chile.  The concentrate would then be
sent to a smelter for processing.  This scenario poses some
logistical and financial challenges, so testwork has been performed
to determine if the concentrate could be processed through a pressure
oxidation process at site to produce copper cathode.  Results from
this testwork were positive and very high extraction rates of copper
from the concentrate were achieved for both primary and supergene
material indicating that producing a cathode on site is possible. 
The benefits of producing a cathode on site instead of a concentrate
include: i) a reduction in export taxes (5% on cathode versus 10% on
concentrate); ii) the removal of the pipeline from the initial
capital expenditures and; iii) the removal of treatment and refining
charges from the smelting process. 
3) Testing of low grade material for suitability in a hea
p leach 
The 2010 PEA was based on a resource that used a cut-off grade of
0.35% copper and a mine plan that used a cut-off grade of 0.205%
copper within the resource pit shell.  All of the material above the
mine plan cut-off will be milled.  Column leach testing was performed
to determine the viability of processing mineralized material below
this cut-off grade through heap leaching.  Positive results were
achieved with an expected copper extraction rate for the run-of-mine
material of approximately 63%.  These results mean that a significant
portion of lower grade material previously considered waste could
potentially be processed.  
McEwen Mining has begun work on an updated PEA which is expected to
be completed in the third quarter of this year.  The updated PEA will
be based on a significantly larger mineral resource and will evaluate
the possibility of increasing the daily throughput.  The updated PEA
will also incorporate the results of these metallurgical studies.  
Los Azules is one of the world's largest, undeveloped, high-grade,
open pit copper projects which, contains significant growth potential
and these metallurgical results only enhance the value of the project
as they demonstrate that the deposit is amenable to proven and
established processing methods. 
About Los Azules  
Los Azules is a large undeveloped 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. Los Azules is one of the world's largest, highest
grade, undeveloped copper-porphyry deposits not owned by a major base
metal company. 
The mineral resources for Los Azules were calculated in January 2013
and are summarized in the table below with a cut-off grade of 0.35%

Mineral Resource   Tonnes   Copper  Contained Copper     Gold       Silver  
    Category     (millions)   (%)       (MM lbs)     grams/tonne grams/tonne
    Indicated        310      0.65        4.45           0.07        1.8    
    Inferred        1,302     0.49        13.95          0.06        2.0    

About McEwen Mining (  
The goal of McEwen Mining is to qualify for inclusion in the S&P 500
by 2015 by creating a high growth 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, Mexico and Nevada. 
McEwen Mining has 296,024,859 shares issued and outstanding. Rob
McEwen, Chairman, President and Chief Owner, owns 25% of the shares
of the Company (assuming all outstanding Exchangeable Shares are
exchanged for an equivalent amount of Common Shares). As of December
31, 2012, McEwen Mining had cash and liquid assets of approximately
US$79 million and is debt free. 
Technical Information: 
Richard S. Kunter, FAusIMM, CP, QP, Chief Process Engineer, Mining
and Metals, Samuel Engineering, Inc., who is a Qualified Person and
independent of McEwen Mining, as defined by National Instrument
43-101 ("NI 43-101") has reviewed and approved the technical content
of this news release. 
For additional information about the Los Azules project see the
Technical Report titled "Los Azules Porphyry Copper Project, San Juan
Province, Argentina" dated August 1, 2012, with an effective date of
June 15, 2012, prepared by D. Ernest Winkler, P.Eng., Robert Sim,
P.Geo., Bruce Davis, PhD, FAusIMM and James K. Duff, P.Geo., all of
whom are qualified persons and all of whom are independent of McEwen
Mining, each as defined by NI 43-101.  The foregoing report is
available under the Corporation's profile on SEDAR ( 
The mineral resource estimate referenced in this news release was
prepared in January 2013 by Robert Sim, P.Geo. And Bruce Davis, PhD,
FAusIMM, each a qualified person and independent of McEwen Mining,
each as defined by NI 43-101 and disclosed in the Corporation's news
release dated February 5, 2013 titled "McEwen Mining Continues to
Expand Los Azules' Large, High-Grade, Mineral Resource. 
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 in Canadian National Instrument 43-101 ("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
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, political 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 the cost of transferring or otherwise
allocating funds between operating jurisdictions, 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 and permitting of mining operations and commencement of
production and the projected costs thereof, risks related to
litigation, 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, 2012 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. 
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 
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