Environmental Assessment
Volume B-3.9
Mine
Water Quality
Ambatovy Project
124
January 2006
additional downstream flow reduction will be achieved by directing
water from the clarification pond to the ore preparation plant.
•
All runoff from the blending stock pile (which may contain up to 100%
low magnesium saprolite) will be diverted to the ore preparation plant.
Water quality information for runoff from different land areas and the sources of
this information used for modelling are summarized in Table 3.9-2. Water
quality in receiving watercourses was based on average baseline concentrations
of substances in watercourses within the mine area for the wet or dry seasons.
The wet and dry seasons corresponded to the months of December to March and
April to November, respectively, which is consistent with the seasons used in the
hydrology assessment.
Table 3.9-2 Summary of Water Quality Information Used for Assessment
Area
Description
Source
mine areas
predicted runoff water quality from mined
areas
geochemistry assessment
(Volume B, Section 3.2)
waste areas
predicted runoff water quality from waste
areas
geochemistry assessment
(Volume B, Section 3.2)
undisturbed areas
average baseline concentration of
watercourses within the mine area
baseline water quality
(Volume I, Appendix 9.1)
disturbed areas (other than
mined or waste areas)
baseline concentrations for the samples with
maximum total suspended solids results
baseline water quality
(Volume I, Appendix 9.1)
reclaimed areas
average baseline concentration of
watercourses within the mine area
baseline water quality
(Volume I, Appendix 9.1)
pond area
concentration of zero was used to represent
substance concentrations in precipitation
not applicable.
All water quality variables, for which sufficient data were available, were
modelled at the mine area (Table 3.9-3). Values for pH were not predicted with
the mass balance model. However, the potential range of pH values at the outlets
of the six basins was characterized for baseline, operations and post-closure
scenarios using data from sources summarized in Table 3.9-2.
