TORONTO, ONTARIO -- (Marketwire) -- 02/05/13 -- McEwen Mining Inc. (NYSE: MUX)(TSX: MUX) is pleased to announce an updated, Canadian National Instrument 43-101 compliant ("NI 43-101") mineral resource estimate for its 100% owned Los Azules Copper Project in San Juan Province, Argentina. Most importantly, drilling has expanded contained copper in the inferred resource category by 29% to 13.95 billion lbs. Contained copper in the indicated resource decreased slightly to 4.45 billion lbs. The expanded resource incorporates 6,966 meters of new drilling from 10 additional holes. The resource remains open laterally, to depth and along strike (to view cross-sections displaying the resource click here). Los Azules is one of the world's largest, undeveloped, high-grade, open pit copper projects which, contains significant growth potential.
Table 1. Los Azules Copper Project - Comparison of Previous and Current Mineral Resource Estimates
============================================================================ January 2013 Resource June 2012 Resource Estimate Estimate Update % Change---------------------------------------------------------------------------- Cut-off Tonnage Cu Tonnage Cu Grade (million Grade Cu lbs (million Grade Cu lbs Contained (Cu%) tonnes) (%) (billions) tonnes) (%) (billions) Cu lbs----------------------------------------------------------------------------Indicated Resource---------------------------------------------------------------------------- 0.35 323 0.65 4.64 310 0.65 4.45 -4%----------------------------------------------------------------------------Inferred Resource---------------------------------------------------------------------------- 0.35 948 0.52 10.82 1,302 0.49 13.95 +29%============================================================================(i)Details for gold and silver resources are included in Table 2.
"Los Azules is a unique asset, in terms of size and grade, for McEwen Mining. This year's exploration drilling has demonstrated that there is significant potential to expand the resource well beyond our previous understanding of the deposit," stated Rob McEwen, Chief Owner.
Drilling this season represents the first time a meaningful amount of deeper drilling has occurred at Los Azules. Prior to this year the deepest drill hole was 650 meters. This season there has been a total of 6 holes that exceeded 700 meters. This deeper drilling has begun to identify a potential parallel trend, west of the original Los Azules ore-body. Copper mineralization discovered within this trend occurs near surface and also at depth (down to 1,050 meters below surface). This is significant because it may indicate that previous shallow drilling, which makes up the majority of the Los Azules resource, failed to adequately test the deeper potential of the deposit. As a result, many new exploration targets have emerged.
McEwen Mining has begun work on an updated Preliminary Economic Assessment (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 PEA will also incorporate further metallurgical studies currently being done on the possibility of producing copper cathode instead of a concentrate and processing low grade mineralized material not previously considered, via a heap leach. The advantage of producing a copper cathode is that it would eliminate the contemplated slurry pipeline through Chile and would reduce Argentina's export tax on concentrate.
