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
8 DEPOSIT TYPE
The Pulacayo deposit has been classified as an epithermal deposit of low to intermediate
sulphidation state or association. Deposits of this type have been extensively researched
and various summary publications that document specifics of the association are available.
Examples of these include Lindgren (1922), White and Hedenquist (1994), Corbett and
Leach, (1998) and Corbett, G.J., (2002). The following discussion of this deposit type is
presented without change from Cullen and Webster (2012), who cited the work completed
earlier by Presasacco et al. (2010).
Pressacco et al. (2010) highlighted the following key geological characteristics of Pulacayo
that support classification as a low to intermediate sulphidation epithermal deposit and
Figure 8.1 provides a schematic summary of the general deposit model:
The vein and disseminated sulphide mineralization is hosted by Tertiary volcanic
rocks of intermediate composition that form part of an outcropping dome
complex.
The mineralized body is composed of narrow veins, veinlets, stock works and
disseminations in argillicly-altered host rock that are controlled by an east-west
oriented fault system. Width of the mineralized zone varies from a few m or less
to 120 m.
Sedimentary rocks intruded by the dome complex host high grade veins such as
TVS that are typically less than 3 m in width but transition to stock work and
disseminated zones in overlying andesitic volcanic rocks that reach as much as
120 m in width.
The sulphide mineralization has been proven to continuously occur along strike
for 2 700 m and to a depth of approximately 100 m below surface.
The vein system mineral assemblages are relatively simple and in combination
are diagnostic of an epithermal setting. They consist of galena, sphalerite,
tetrahedrite, and other silver sulfo-salts that form the main assemblage of
economic interest and barite, quartz, pyrite and calcite that are present as
gangue phases. Chalcopyrite and jamesonite are present in minor amounts
locally.
Internal texture of veins is typically banded and drusy with segments containing
almost massive sulphides. This is typical of epizonal veins that have been
subjected to multiple pulses of mineralizing fluid.
Vertical metal zonation exists within the deposit that includes a mid-elevation
zone of highest silver values that transition with depth to progressively increasing
total base metal concentrations.
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