Stockwork

The, quartz sulfide stockwork, which is the host rock for mineralization, trends east and west of our recent drilling in this area and remains open on both ends and at depth for additional drilling. ❋ Unknown (2010)

The rocks are weakly to moderately altered with sericite, silica, and fine quartz stockwork veinlets.

Drilling to date has now intersected typical Concordia vein stockwork mineralization on a minimum spacing of 100 meters over a total strike length of 1,000 meters.

A 3200 meter drilling program in 2005 led to the encouraging discovery of broad stockwork and narrower high-grade zones, with concentrations as high as 49.30 ppm gold across 1.53 meters.

REE mineralization in the Bull Hill SW resource area is contained within intrusive dikes, veins, and stockwork of FMR, transitional carbonatite, and carbonatite that invade heterolithic intrusive breccia of the Bull Hill diatreme. ❋ Unknown (2011)

Ubiquitous fine disseminated chalcopyrite is generally correlative with the density of quartz-sulfide stockwork veinlets, which peak at a density of about 40% by volume near 275 meters, and gradually diminish to about 5% by volume at the end of the hole.

The channel sample was taken from a zone of disseminated stockwork mineralization near the intrusive contact.

Preliminary geological mapping and projection of FMR intercepts in drill holes suggest that the REE mineralization consists of dikes and adjacent stockwork with dimensions of roughly 700 feet (210 meters) east-west by 250 feet (75 meters) north-south, and the mineralization is open to the east.

Overall, the mineralization occurs in a sericite-carbonate +/- albite altered dacitic volcanic complex with zones of quartz veins, quartz stockwork and quartz breccias.

In Phase I, vein outcrops, mostly in the form of stockwork, were mapped and 187 samples were collected for assay analysis.

Fred Earnest, Vista's President and COO commented, We are pleased to see the continuity of the mineralization in the stockwork along strike being confirmed by the surface samples, which together with the information from historic mining activities and more recent drilling, also confirm the continuity of the underlying vein system.

Chip samples collected from the stockwork surface expression of the veins contain silver grades as high as 653 g/t and gold grades as high as 7.3 g/t.

Quartz-sulfide stockwork veinlets and associated fine disseminated chalcopyrite are ubiquitous throughout the entire hole.

Holes QTA 157 and QTA 168 drilled respectively 400 meters and 500 meters west-southwest of QTA 123, each intersected thick intervals of stockwork mineralization, with a best intercept of 42.8 meters of 46 g/tonne silver in hole QTA 168.

The strongest mineralization encountered was a zone of intercalated "salami" granite, andesite, and aplite containing a stockwork to sheeted quartz + pyrite veinlets with visible gold, identified in a hole located approximately two kilometres southeast of the deposit.

Disseminated chalcopyrite is ubiquitous and generally correlates with the density of quartz-sulfide stockwork veinlets, which peak at a volume of about 30% near 150 meters, and very gradually diminish to a volume of about 5% at the end the hole.

A summary of the results of this sampling program can be seen in the maps, together with typical sections showing the relationship between the stockwork and Low Sulfidation Epithermal LSE veins which can be found on our website at The initial results from Phase I are being used to define gold-silver zoning in the district to evaluate prospective horizons within the vein system.

Detailed mapping suggests that the REE mineralization consists of northwest-striking FMR dikes and an FMR stockwork zone that is elongate northeasterly, with dimensions of roughly 1250 feet (380 meters) by 950 feet (290 meters).

Most of the currently estimated mineral resources for the Guadalupe de los Reyes district is hosted by the near-surface stockwork overlying the LSE vein system.