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.
Conclusions
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.
Firesteel’s
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.
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