Regional Geology  

The Virimoa property is underlain mainly by andesitic volcanic rocks of Lower Tertiary age. These rocks are overlain in the southern part of the property by Upper Tertiary rhyolites and andesites, which form cliffs and ridge tops. The upper part of the Lower Tertiary assemblage hosts most of the important deposits of the Sierra Madre Occidental Gold and Silver District.

Mining History 

The Virimoa property is located in an area with a long history of small-scale mining. Numerous old mine workings are located about 2 km to the north of the property. Most of the production likely came from the San Cayetano mine. A study of San Cayetano by Mexican government geologists showed that production came from three levels and from ore that graded in the order of 0.7g/t gold and 300-400 g/t silver. 

Property Geology  

Geological mapping and rock sampling has been concentrated on a prominent northwesterly trending argillic-siliceous alteration zone. This zone is at least four hundred meters long and 200 meters wide. Much of the area is overburden covered, and this limits the extent of surface sampling. Chip sampling was carried out along creek banks and road cuts which exposed strongly pyritic and clay-altered andesites and rhyolites. Some of the volcanics contain rounded fragments, which may be hydrothermal breccias. The altered volcanics are cut by a well developed system of northeast trending sheeted sulphide rich veins and pods up to two meters wide. Continuous chip samples collected during a previous evaluation shows highly anomalous metal values over a straight-line distance of approximately 350 meters. The width of the zone is unknown but is at least 200 meters. Within this zone, a 160-meter section returned a weighted average grade of 1.1 g/t gold, 17 g/t silver. This section also has a high zinc content (1.12%), minor lead (0.15%) and copper (0.1%). A 30-meter section at the extreme southern end of the previous sample traverse returned 2.79 g/t gold, 21.9 g/t silver and 3.43 % zinc. This high-grade section occurs near the contact with the overlying unaltered andesites and rhyolites. Chip sampling of a road-cut 150 meters southwest of the sampled creek returned 60 meters of 46.6 g/t silver. These results suggest that the various metals may exhibit a zonal distribution.

 Firesteel re-sampled this area as part of a thorough due-diligence evaluation of the property. Nine chip samples collected over 350 meters returned an arithmetic average of 1.04 g/t gold, 59.4 g/t silver and 1.1% zinc. A 16-meter continuous chip sample at the end of the traverse (same location as the high-grade samples reported by the earlier operator) returned 3.38 g/t gold, 26.2 g/t silver and 4.93% zinc.


Work to date, although very limited, has indicated that a large area has been subjected to intense, hydrothermal activity with associated gold, silver and base metal mineralization. Ore thickness and grade have been established by 2 separate rock chip sampling programs. The strike length of the zone is at least 350 meters and open in all directions. By analogy to similar deposits in the Sierra Madre District, some of the best grades can be expected to occur near the top of the Lower Andesite unit. At this level the mineralized fluids can be ponded and spread laterally below the impermeable cap rock of the Upper Andesite and Rhyolite unit.  

As exploration continues, it is likely that the mineralized zones will be extended and become better defined. The potential for a gold resource in excess of one million ounces is thought to be excellent.  

Firesteelís immediate objective is to define a world-class precious metal deposit similar to those already known throughout the Sierra Madre District. To accomplish this goal, Firesteel is planning a program of soil sampling, ground geophysics (induced polarization), trenching, rock sampling and geological mapping. A drilling campaign will evaluate targets identified by this exploration program.


Virimoa Property

View to the SE

NW Zone

Road from Canelas to Birimoa

SE Zone

SE Zone - Check Person for Scale

Detail of previous picture  showing the stockwork pattern.