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
Item Description Units Value Source
A: Provided by owner
B: Standard industry practice
C: Provided by consultant (see the Anddes design report)
D: Criteria based on calculations and analysis
tailings, clay &
organic vegetative
layers
18.9.4 Design and operational Components
During normal operations, tailings will be pumped from the paste plant, without cement addition,
and distributed around the impoundment using conventional moveable pipes and discharge
points (pipe “tees” or, if practical, spigots).
Annually, usually two dikes will be raised each year. The four starter dikes will be constructed
with locally available soils (Dikes 1 & 2 with structural fill, Dikes 3 & 4 with random or mass fill).
Each raise will be constructed using paste tailings with Portland cement added at 3.0% by dry
weight; other binders such as pozzolanic fly ash or polymer amendments may be used, subject to
testing, to reduce the cement demand or improve performance. Each raise will be nominally 4
meters of elevation gain such that the rate of rise is maintained at a very low rate (4 m per year in
the early years, then declining as the working impoundment area increases), allowing the tailings
to dry and consolidate and avoiding the development of excess pore pressures.
Dike raises will use modified upstream methods, as shown in the following figure. The area
between the two down-stream dikes (Dikes 1 & 2) will be filled with cement-treated tailings to
provide robust global and post-closure stability and erosion protection.
The tailings behind the other dikes will not generally contain cement, except for the first layer to
seal the basin. The total quantity of tailings to be treated with cement is 584,300 t, or about 36%
of the total tailings to be deposited in the TSF.
TWP Sudamérica S.A. Av. Encalada 1257 Of. 801, Santiago de Surco Lima 33, Perú (51-1) 4377473
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