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
Table 13.6 Fourth Sample Composite Head Core Grades and Assays
Sample ID Core Details Estimated Core Grades Head Assays
Size, kg Ag, g/t Pb, % Zn, % Ag, g/t Pb, % Zn, %
UTO Sample 68.6 Half Core 225.8 0.63 1.1 270 1.04 2.13
13.7.2 Sample Preparation and Testing Procedure
The bulk sample preparation and testing procedure was as follows:
Crushing
Sample homogenization, quartering, and sample sizing for flotation tests
Single bulk flotation test (1)
Open circuit differential flotation tests (4)
Single locked cycle differential flotation test (1)
Bulk flotation tests under PORCO flowsheet (6)
13.7.3 Open Circuit Differential Flotation with a De-sliming Step
A single bulk flotation test (Test N° 1) was carried out to identify the floating fraction of the ore
(sulphides) and to have an indication of metal losses. In addition, a series of open circuit
flotation circuit were carried out to determine the flotation performance (range of concentrates
grades and recoveries obtained by differential flotation). Then, a locked cycle test was carried
out under the most suitable conditions (Test N°6).
The first exploratory test indicated that silver recovery to bulk concentrate is about 72%, while
the lead and zinc recoveries are approximately 66% and 78%. The floating fraction account
for about 13% w/w while the slimes fraction is 18%, the rest is lost as final tailings. Lead and
silver losses are up to 23% and 13%, respectively.
A series of open batch flotation tests were performed. The results indicated that lead
recovery is in between of 48% and 54%, while zinc recovery is in the range from 50.1% to
72%. Total silver recovery to both lead and zinc concentrates is in between 30% and 68%.
Lead concentrate grades range from 33.5% to 59%, zinc concentrate grades is in between of
49% and 55%. Similarly, silver grades in both concentrates range from 9,875 g/t to 15,333
g/t.
A single locked cycle test (LCT), a repetitive batch used to simulate a continuous circuit
where all the intermediate material added to the appropriate location in the flowsheet, was
conducted to produce a metallurgical projection of the sample tested and to assess if the
flowsheet and reagent suite is stable.
A good locked cycle test achieves steady state, typically over the last three cycles. Steady
state implies both stability and mass conservation. Stability implies constancy.
It was not indicated whether the test reached stability or whether mass conservation was
achieved. Assuming that steady state was reached, the results indicated that lead and zinc
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