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
company was appointed to supply data collection to KCB. TWP Sudamerica delivered the water
balance to be considered in modeling the water supply. KCB conclusions are as follows:
Water balance calculations indicate that while the Yanapollera reservoir should be able to satisfy
demands of the mine in addition to users from Pulacayo and Uyuni under average conditions, the
extreme climatic conditions of the region result in a statistically significant likelihood that the mine
will experience water deficits during the projected 12-year mine life. Seasonal variation inflows
combined with the limited storage capacity of this reservoir is a significant contributor to this
potential lack of water – the reservoir exhibits a significant annual surplus which is largely
discharged either in Pulacayo or downstream of the impoundment. Constructing additional water
storage and supplementing mine water supply with groundwater is expected to significantly
improve water security. Sensitivity analyses indicate that the results presented in this report are
sensitive to a number of variables; most notably the water demand of Uyuni and Pulacayo and
the behavior of groundwater springs in the wetlands upstream of Yanapollera. Further calibration
of data inputs and validation of model outputs is required for reliable model predictions. Due to
the variability of climate conditions and the inherent uncertainties of this predictive analysis, KCB
recommends that an integrated system including groundwater supply and water storage be
considered to reduce the chance of temporary mine shutdown due to water shortage. KCB
recommends that a groundwater supply investigation be undertaken, in addition to on-going
monitoring of site surface water flows and local and regional climate data, in order to improve the
level of confidence of subsequent water supply analyses.
Apogee requested KCB to develop two complementary studies to reinforce water supply: Design
of reservoir to increase water storage capacity, and a Shallow Groundwater Supply Investigation.
Both, at the time of writing this report are being developed. The intention to develop these two
studies is to address the best option suggested by the consultant which is a combined one,
increasing water storage capacity and sourcing from somewhere other than the Yanapollera
reservoir.
18.5.1 Surface Water Management
Surface water runoff that has not come into contact with tailings (“non-contact” water) shall be
captured by perimeter diversion channels and routed around the dry stack to discharge to the
natural drainage down gradient of the facility. Efforts should be made to minimize water run-on to
the TSF. Since the TSF footprint will increase over the operations lifetime, construction of
temporary diversion channels for different expansion phases of the TSF will be required.
A fresh-water pipeline will deliver the water to the project Raw Water/Fire Water Tank, located at
the Project site at an elevation of approximately 4,500 m. Any water in excess of the plant raw
water requirements would be directed to the Process Water Tank located adjacent to the process
facilities.
18.5.2 Firewater Distribution
A fresh water pipeline will deliver fresh water by gravity for firefighting services.
Individual hand-held fire extinguishers will also be located throughout the offices and work areas.
TWP Sudamérica S.A. Av. Encalada 1257 Of. 801, Santiago de Surco Lima 33, Perú (51-1) 4377473
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