Argonaut Gold Announces Updates on the Magino and San Agustin Projects

TORONTO, ONTARIO--(Marketwired - Jan 12, 2015) - Argonaut Gold Inc. (AR.TO) ("Argonaut", "Argonaut Gold" or the "Company") is pleased to provide updates its Magino and San Agustin projects. Argonaut has received results of the metallurgical test work on three rounds of column testing at various crushing methods and sizes on its 100% owned Magino project located in Ontario, Canada completed by Kappes Cassiday and Associates ("KCA") of Reno, Nevada. Argonaut has also received the results of a Preliminary Economic Assessment ("PEA") for its 100% owned San Agustin gold project, located in Durango, Mexico completed by KCA; Resource Modeling Inc. ("RMI") of Stites, Idaho and Argonaut Gold's management team. Argonaut will file a full technical report in support of the PEA work within 45 days of this announcement. All amounts are in US Dollars unless otherwise stated.

Magino Metallurgical Highlights

KCA conducted three separate series of column leach tests to examine the feasibility of heap leaching Magino lower grade gold mineralization. Bulk samples were tested from stockpiled material remaining from historic underground operations. In addition, a number of composites were prepared from split drill core collected from various locations throughout the resource volume. Column test work conducted at the KCA laboratories provided the following results:

  • August 2013 column leach test work on materials varying from run-of-mine ("ROM") size to a crush size of 9.5mm. This resulted in recoveries ranging from 38% on the coarser fraction to 68% on the finer material.

  • February 2014 column leach test work on crushed materials ranging from 31.5mm to 12mm resulted in recoveries varying from 40% on the coarser fraction to 61% on the finer crushed material.

  • December 2014 column leach test work comparing conventionally crushed material versus high pressure grinding roll (HPGR) crushed material at minus 9.5mm size resulted in recoveries ranging from 62% to 66% for the conventionally crushed material and 68% to 71% on the HPGR material.

McClelland Laboratories Inc. ("MLI") conducted a test program aimed at optimizing the cyanide concentration in leach in order to minimize cyanide consumption. Three sample composites were prepared from split core representing from multiple intervals within the Magino deposit. The three composites selected represent shallow, mid-level and deep mineralization.

  • Metallurgical testing on milled material resulted in improved cyanide consumption with a nearly a one third decrease in usage. This should reduce operating costs as cyanide accounted for over 23% of plant operating costs assumed in the previously released January 30, 2014 Magino project pre-feasibility study (the "Prefeasibility Study" or "PFS").