Sulliden ready to drill at Santo Toribio in Peru

Promising early results from the Santo Toribio project in Ancash department in west-central Peru offer Sulliden Exploration (SUE-M) hope it can imitate a nearby success story.

Santo Toribio is about 7 km northwest of Huaraz, and is beside the road leading from Huaraz to the Pierina gold mine, recently opened by Barrick Gold (ABX-T). The property is relatively small (about 9 sq. km) but contains several surface showings Sulliden is poised to drill this month.

Recent mapping and surface rock sampling programs, along with some limited pitting and trenching, led to the discovery of three mineralized areas on the property and provided evidence that the property has similar geology to the Pierina area.

Santo Toribio’s epithermal system is in andesites and dacites, both fragmental rocks and volcanic porphyry. These are cut by a major northwest-striking block fault, the Callejon de Huaylas graben. Northeast-striking veins run across the fault and host sphalerite, galena, silver and pyrite in vuggy quartz. The volcanic rocks, named the Calipuy formation, form the same rock unit that hosts Pierina, 3 km to the north.

Resemblance to Pierina does not stop at the host rocks. Like Pierina, Santo Toribio sports a pronounced argillic alteration zone, where host rocks are converted to clay minerals. The zone envelops the veins and is spread through the more porous fragmental rocks in the Calipuy sequence. More localized zones of strongly silicifed rocks, which form prominent ridges, concentrate around mineralized surface showings.

Petrographic work to map zones of alteration has made up a large part of Sulliden’s effort on the project so far. In one area near the property’s western boundary, a “silica cap,” about 500 metres long and 300 metres across at its widest point, hosts gold and silver mineralization. There, surace bedrock samples detected gold and silver, along with three elements commonly found to be “pathfinders” for precious metals: arsenic, antimony and lead. Grab samples of vein material yielded grades of 2-5 grams gold and 200-1,700 grams silver per tonne.

On the eastern side of the property, the Boliche and Rubia prospects are in an area where argillized Calipuy volcanics are cut by a network of quartz-sulphide veins, some of which are parallel to the northwest-striking Huaylas graben, whereas others are at nearly right angles to it.

Here, again, surface sampling of the rocks revealed gold and silver, plus the pathfinder elements. The veins themselves are made up of quartz, carbonate, and iron oxides, plus pyrite, sphalerite, arsenopyrite, stibnite and galena.

Drill programs on both the Silica Cap showing and the Boliche-Rubia area are scheduled to start this month.

Sulliden’s option deal on the property obliges it to perform US$2.5 million in exploration work by March 2002. It then has the option to buy a 50% interest for US$1.15 million from Peruvian-based Minera Santo Toribio.