Minera Alamos Inc. is pleased to provide updates on the ongoing metallurgical testwork targeting gold recovery optimization at its La Fortuna Gold Project located in Durango Mexico.
Further metallurgical work is underway to evaluate an optimal plant flow sheet to be incorporated in the Pre-Feasibility Study ("PFS") scheduled for release later this year.
"Compared to typical gold heap leach recoveries, these new results represent an approximate 50% increase in potential gold production from the La Fortuna gold resource. In addition, the ability to pre-concentrate the gold prior to leaching allows for further reductions in the scope and capital required for downstream processing equipment", said Darren Koningen, President of Minera Alamos. "These favorable results allow us to consider alternative processing methods other than heap leaching, possibly increasing the economic potential of the project significantly".
- Gold is predominantly in the form of free grains that are readily recoverable. Based on the samples tested, recoveries averaging approximately 98% were achieved via direct cyanidation of the ground mineral samples;
- GRG (gravity recoverable gold) results demonstrating that in excess of 80% of the gold from the sample materials can be achieved via centrifugal gravity concentration alone;
- 97-98% of the gold reports to a high grade bulk flotation concentrate representing only 10% (by mass) of the initial sample material;
- High gravity/flotation recoveries are maintained at relatively coarse grind sizes in excess of 200 microns.
Summary of Metallurgical Testwork
The ongoing metallurgical testwork program for the La Fortuna project is being performed at SGS Canada Inc. located in Lakefield, Ontario. SGS Canada is an ISO/IEC 17025 accredited metallurgical testwork and analysis facility with an extensive history of gold process development activities, and is at arm's length to Minera Alamos.
Samples for the current round of testwork were taken from available diamond drill core from previous drill programs at the La Fortuna project (2008 twin hole drilling program). Core was selected from eight different intervals that represented both high and low grade zones within the deposit as well as different drill depths. The samples were prepared and assayed individually prior to being used to prepare both high (approximately 4 g/t) and low (approximately 2 g/t) grade gold composites.
Material from these two composites was then utilized for a series of metallurgical campaigns that included:
- Conventional ground ore bottle rolls (72 hours);
- Gravity recoverable gold testwork utilizing centrifugal concentrator (Knelson) techniques; and
- Bulk flotation of the gold/sulphide content remaining in the tailings from the gravity concentration tests.
Additional testwork is currently ongoing and is focusing on the following:
- Optimization of grind sizes for the gold/sulphide flotation;
- Maximization of the gravity recoverable gold content of the mineralization; and
- Cyanide leaching of the gravity and flotation concentrates.
Further updates on the metallurgical program will be provided as they become available.