Summary:
The Inmaculada deposits can be clasified as low to high sulfidation epithermal silver-gold deposits. Deposit sub-types on the Property includes LS type which includes the Au-Ag quartz veins at Quellopata including the Angela Vein, IS type and HS type which includes mineralized breccias at Minascucho, Central and San Salvador and disseminated mineralization at Tararunqui.
Target vein structures are hosted in Tertiary-age volcanics and are associated with several episodes of mineralization. Average vein thicknesses range between 0.8-4.0 m in width and the majority of vein systems tend to be silver rich, although local variations do occur with zones of lower Ag: Au ratios.
Detailed mapping showed that the dominant rock type which hosts the Quellopata veins is andesite / andesite breccia of the Oligocene Tacaza Formation. The mapping also showed that the veins were predominantly northeast-trending, with the exception of the southwestern portion of the area where they trend more westerly. Rock chip sampling has shown that consistently high gold values (from 1 to over 10 g/t Au) are present in the Angela Vein, in the vicinity of line 10,000N of the local grid. This exposure of higher grade veining occurs in the valley. The better- grade material does not reach surface over much of the vein's strike length although quartz veining can be seen. The veining at surface has opalescent quartz with only rare bladed calcite pseudomorphs or colloform banding.
Northwest trending, southeast dipping faults are the oldest structures at Quellopata and host the eight known veins: Angela, Roxana, Martha, Teresa, Lourdes, Shakira, Juliana and Lucy.
The Angela Vein outcrops in the central portion of the Quellopata vein system. The vein strikes northeasterly (050º), dips to the southeast (45º to 90º) and outcrops on surface along a strike lenght of 700 m.
The vein varies in thickness from 0.5 m to us much us 16.0 m, and has been tested over a vertical extent of up to 3000 m.
Two generations of mineralization have been observed in the Angela Vein, an early lead-zinc event and a later gold-silver event. The early mineralization consists of white quartz veinlets with sphalerite, galena, pyrite and argentite (minor). These veinlets form a broad, low-grade envelope (0.2 to 1.0% Pb + Zn) which surrounds, and overlaps, the Angela Vein mineralization.
The second mineralizing event at the Angela Vein is the most important economically, and consists of a white chalcedony vein with associated breccia and stockworks. The chalcedony contains small amounts (generally <1%) of electrum, argentite, pyrargyrite, chalcopyrite, pyrite and marcasite.
The Angela Vein is composed of a gangue of white chalcedony, quartz, calcite (minor), smectite and illite. Pseudomorphic, quartz-after-calcite textures, and colloform banding, both indicative of boiling, are quite common in the vein. Metallic minerals, which rarely constitute more than 1% of the vein, occur as disseminations and colloform banding, and consist of pyrite, marcasite, argentite, pyrargyrite, chalcopyrite, sphalerite and electrum.
The andesitic wall rock surrounding the Angela Vein is altered to a propylitic assemblage consisting of smectite, chlorite and disseminated pyrite. Quartz stockworks, some containing significant quantities of base metals, are common in the wall rock adjacent to the vein.