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
remaining mineral reserves along Level Zero should continue to be extracted using shrinkage
stoping.
Long hole stoping, supported by a fleet of trackless equipment, is recommended for
extracting the mineral reserves below Level Zero. Owing to the low strength of the rock mass,
the stopes will require backfilling to ensure stability post ore extraction. The reasons for
selecting this method instead of sub-level caving are listed below:
The mining method allows for selective mining of high grade veins,
The mining method will make use of process plant tailings in the backfill, thus
minimizing the footprint of the tailings dam on surface and associated
environmental liability,
The use of cemented backfill is required for geotechnical stability. This will allow
for maximum ore extraction without compromising on run-of-mine (ROM) grade
while mining stopes adjacent to each other,
Better control of dilution,
A higher degree of flexibility in the mining sequence.
Mining will be undertaken using a top down approach (i.e. access and infrastructure will be
developed to the ore body as required). The main objective of using this approach will be to
minimize capital expenditure in the early years of the operation.
16.2 Mine Design and Layout
16.2.1 Shrinkage Stoping
The shrinkage stopes will have a design stoping height of 30 m and a stope length of 30 m.
The stope width will depend on the thickness of the payable vein, which varies between 0.8
m and 2 m. Figure 16.1 shows a typical layout of a shrinkage stope at Pulacayo mine.
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