Resource
The last reported resource for the project was in September 2009, based on 165 drillholes (84 core, 81 RC). At a nominal 0.25 grams per tonne (“gpt”). gold cutoff, the measured and indicated resource estimate includes 15.9 million tonnes grading 0.706 gpt gold and 9.4 gpt silver totaling 360.000 ounces of gold and 4.8 million ounce of silver. An additional 47,000 ounces of gold with 480,000 ounces of silver at the same cutoff are classified as inferred resources. This resource calculation has been supported and filed by a 43-101 technical report. The report was filed on SEDAR on October 21, 2009. An updated resource calculation was contained in the 43-101 technical report files on SEDAR on August 23, 2010.
Metallurgy
Favorable metallurgical results for the project were announced in May 2009, with gold recoveries ranging from 72 to 82% for a range of crush sizes between 3/8“ to 1”. Selection of optimal ore crush sizes based on the metallurgical results will be one of the objectives of the economic analysis in the current pre-feasibility study. Additional detailed information on the metallurgical results is available in the May news release.
Mineralization
The gold-silver mineralization at La Bolsa occurs within stockwork and disseminations that are generally located within a low-angle north-south trending structural zone that dips moderately eastward from its exposure along a north-south-trending ridge. Mineralization is in the form of an oxidized blanket that is sub-parallel to topography and then dips shallowly below surface from the base of the ridge.
Mineralization has been traced for approximately 1,000 meters (3,300 feet) in length and up to 800 meters (2,600 feet) in width with thicknesses that range from 10 to 50 meters (30 to 165 feet). Recent drilling at La Bolsa continues to extend that zone, and the known mineralization remains open both down-dip and along strike.
Gold and silver enrichment at La Bolsa typically occurs in association with disseminated ironoxides and quartz – calcite and quartz – adularia veins and stockwork. Quartz veins are finely crystalline to chalcedonic while calcite veins tend to be coarsely crystalline, vuggy, or locally massive. Red, orange, and brown iron-oxides and brown to dark gray manganese oxides are often associated with the veining. Alteration of the volcaniclastic sediments, flows, and intrusive rocks consists of silicification, adularization, local argillic alteration, and iron oxides after less than 5 percent sulfides. The hydrothermal fluids that deposited the gold-silver mineralization are interpreted to have been of epithermal low-sulfidation character.
A substantial extension to the mineralization at La Bolsa was announced July 2009, with the reporting of drill results from the 2009 drill program. Step-out drilling has encountered a significant new zone of gold and silver mineralization approximately 200 meters east of the current La Bolsa resource. These initial drill results confirm the presence of high-grade gold and silver mineralization including 6.0 meters containing 12.063 gpt Au and 109.8 gpt Ag (19.7 feet with 0.352 opt gold and 3.20 opt Ag), and 20.5 meters containing 2.099 gpt Au with 35.4 gpt Ag (67.3 ft with .061 opt Au and 1.03 opt Ag). While these results represent a significant expansion of the mineralized zone at La Bolsa, additional drilling is required to assess the extent and full potential of this newly discovered mineralization.