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
activation of sphalerite and pyrite by copper ions (Cu 2+ ) dissolved from copper minerals
(mainly chalcopyrite) hampers lead flotation selectivity.
13.2.5 OCT Tailings and Flotation Feed Size by Size Analyses
Results indicated that, most of the valuable metal losses occur at mesh sizes less than 74
µm (200 #) for all the OCT tailings samples tested.
13.2.6 Sedimentation Test work
A set of thickening tests were run on tailings slurry samples of the OCT flotation tests. The
results indicated that higher sedimentation velocities (lower unit areas) are obtained for the
tests carried out after a cycloning step (desliming).
13.3 ED&ED Lab Metallurgical Test Program (Stage 3)
In 2011, the laboratory facility of ED&ED Ingeniería y Servicios S.A.C. (ED&ED) in Peru,
received material from the Pulacayo Project. Two (2) head samples were sent to ASL who
were contracted to undertake mineralogical analyses (PUL-HG and PUL-LG) and a series of
flotation tests.
The initial ED&ED flotation test work was not successful as the zinc floated with the lead in
the lead differential float. ED&ED then pre-conditioned with activated carbon and subsequent
differential flotation was moderately successful.
13.3.1 Third Set of Samples
ED&ED lab received material from the Pulacayo Project. Individual drill cores were combined
to generate a high grade composite (PUL-HG) and a low grade composite (PUL-LG). A
summary of the estimated core grades and assays are shown in Table 13.6.
Table 13.5 Second Sample Composite Set Grades and Head Assays
Sample ID Core Estimated Core Grades Head Assays (*)
Size, m Ag, g/t Pb, % Zn, % Cu, % Ag, g/t Pb, % Zn, % As, %
PUL-HG 23.22 705.6 3.45 7.98 0.19 225.1 1.58 2.24 0.11
PUL-LG 250 132.9 1.36 2.77 0.03 178.23 0.91 1.79 0.09
13.3.2 Mineralogy
The results of this study indicate that the main mineral specimens present in both samples
were sphalerite, galena, pyrite and quartzite gangue. Galena-sphalerite assemblages
(intertwined specimens) are present to some extend. The latter may be the reason for some
not desired zinc content in the lead concentrates.
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