New Metallurgical Studies At Los Azules Project

TORONTO, ON - McEwen Mining Inc. reported new metallurgical studies has 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.

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%.

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.

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.