Pulacayo Project Feasibility Study - Apogee Silver

Pulacayo 1 000 t/d Phase I Feasibility Study - NI 43-101 Technical Report
090644-3-0000-20-IFI-100
domes and stocks associated with caldera resurgence that intrude the folded section. A
younger Miocene-Pliocene phase of volcanism is also superimposed on the anticlinal trend
and is marked by pyroclastic deposits and flows of andesitic and rhyolitic composition.
Ignimbrites associated with the Cosuño Caldera are the youngest volcanic deposits in the
area. A dacitic to andesitic dome complex at the Pulacayo property intruded the folded
sediment section and forms the main topographic highs that occur on the property (Figure
7.3).
7.3 Structure
The Pulacayo, Paca Mayu and Paca volcanic dome complexes occur along a north-south
corridor defined by two parallel, north-south trending regional faults that are separated by
about 2.7 km. The domes occur over an interval measuring approximately 10 km in length
and polymetallic vein and wall rock mineralization at Pulacayo is controlled by east west
trending secondary faults that cut Tertiary sediments and volcanic rocks of the Pulacayo
dome (Figure 7.4). The stock work vein system was emplaced on the southern side of the
Pulacayo dome complex and is best exemplified by the Tajo Vein System (TVS). The TVS
bifurcates in andesitic rocks to form separate veins that collectively form a dense network or
stock work of veinlets along strike. The bifurcating, polymetallic veins are commonly
separated by altered andesitic rock that contains disseminated sulphide mineralization.
Figure 7.4: Structural Interpretation For Tajo Vein System At Pulacayo (Iriondo Et Al.,2009)
The TVS is almost 2,700 m in strike length at surface and is still present at a depth of
1,000 m below surface, the lowest level in the underground mine. In the upper levels of the
mine, the stock work vein system locally reaches approximately 120 m of mineralized width.
The polymetallic veins exhibit a sigmoidal geometry along strike, which is generally
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