Yamana Completes Underground Mining Studies for Gualcamayo

Along with a recent decision to employ front caving with pillar recovery as the mining method of choice for
future ore zones at its Gualcamayo underground mine, Yamana Gold began commissioning surface operations
at the mine late in 2008 and expects to begin commercial production from the pit in 2009.
Shown here is the mine’s leach pad under construction. (Photo courtesy Yamana Gold).
Yamana Gold has completed studies related to underground mining at its Gualcamayo project in San Juan province, northern Argentina. Two mining methods— shrinkage fill and front caving with pillar recovery—were considered for mining the project’s QDD Lower West underground deposit. Both methods are considered feasible; however, Toronto, Canada-based Yamana said it selected front caving with pillar recovery because it increases total minable ounces, reduces costs, provides significantly improved returns, allows for the expansion of resources, better addresses geotechnical constraints, and provides for a longer mine life and a higher return and value.

Shrinkage fill would have allowed faster development, with production potentially to begin in 2011. Front caving under current planning would not begin until 2015, but would effectively extend Gualcamayo mine life from nine to at least 13 years.

The QDD Lower West mineral resource estimate, based on a cut-off grade of 1 g/mt gold, currently includes measured and indicated resources of 8.26 million mt grading 2.90 g/mt, containing 769,000 oz of gold, and inferred resources of 1.60 million mt grading 2.66 g/mt, containing 136,000 oz of gold. The deposit remains open, and Yamana has allocated almost its entire $6-million exploration budget for Gualcamayo in 2009 toward further exploration of QDD Lower West. The exploration program includes about 100 m of underground development and 10,000 m of diamond drilling to extend the deposit along strike to the west.

The current analysis for the front caving approach assumes that underground mining would begin in the area below the main QDD open-pit, which is the area where most currently defined resources are located. However, Yamana is also considering initiation of underground mining in the western extension of the deposit, also using the front caving method, but with the potential for an earlier start for underground production, if additional resources are defined in the western area.

Yamana began commissioning surface operations at Gualcamayo during the fourth quarter of 2008 and is targeting commercial production for the second quarter of 2009. The open-pit, heap leach mine is expected to produce in the range of 195,000 to 210,000 oz of gold during 2009 and 220,000 to 235,000 oz in 2010.

As featured in Womp 2009 Vol 02 - www.womp-int.com