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
recoveries were 60.1% and 76.5%, respectively. Lead concentrate assayed 11,114 g/t Ag,
49.1% Pb and 4.81% Zn. Additionally, the metal values in the zinc concentrate were: 2,220
g/t Ag, 2.29% Pb and 48.6% Zn. Concentrates account for about 2.9% w/w of the feed
(0.81% lead and 2.1% zinc). Silver metal loss in the slimes is as high as in the tailings. Lead
and silver losses in the final tails are 23.1% and 9.12%. Some factors affecting selectivity in
the differential flotation of lead – zinc ores needed to be further explored.
The LCT reagents consumption is as follows: 150 g/t ZnSO 4 , 9 kg/t lime, 50 g/t Z to 11, 60 g/t
MIBC; 75 g/t ZnSO 4 : NaCN complex, 40 g/t AP3418 and 250 g/t CuSO 4 .
The PORCO flowsheet is basically a bulk flotation followed by lead and zinc flotation, this
processing route should be carried out at high pH (12.2) intended to depress pyrite at the
outset. However, the Pulacayo ore did not respond well mainly because of lead and silver
selectivity issues and high consumption of acid (H 2 SO 4 ) to drop the pH to a level suitable for
lead flotation after the bulk stage. Herein, the results of these tests are not present and will
not be further discussed.
13.8 MAELGWYN Metallurgical Test program (Stage 4)
Maelgwyn Mineral Services Africa (MMSA) carried out laboratory flotation optimization test
work on ore samples from the Pulacayo property.
The objectives of the test work were:
Initially to test the flotation conditions supplied by Apogee on the core samples to determine
the metal recoveries and grades achievable by differential flotation of the Pb and Zn minerals
Subsequently to optimize the flotation conditions for effective differential of the Pb and Zn
minerals and to achieve saleable grades Pb and Zn concentrates.
Locked Cycle testing of the optimized flotation conditions on selected variability core samples
(7 cycles, steady state reached over the last three cycles).
13.8.1 Fifth Set of Samples (Variability Samples)
Initially a bulk sample of approximately 300 kg was delivered to MMSA for the test work. After
limited test work on this sample it was realized that the head grades were lower than
expected. Apogee Silver then supplied another higher head grade bulk sample of
approximately 500 kg. Later, during the test work Apogee Silver also supplied 9 variability
core samples.
Each of the bulk and variability samples were crushed to