Environmental Assessment
Volume B-3.9
Mine
Water Quality
Ambatovy Project
136
January 2006
•
Chromium is the key substance of concern with project-related loadings
during operations potentially increasing concentration of this substance
in all basins above both baseline concentrations and the most
conservative (i.e., based on the hexavalent form) South African
guideline value for aquatic life.
•
The highest concentrations of chromium will occur in the basins
draining the Analamay area.
•
During the project operations phase, concentrations of zinc in the
Ambatovy basins (Antsahalava, Sahaviara and Sahamarirana) will
potentially increase marginally above background concentrations and
the South African guideline value for aquatic life.
•
Water quality in the Torotorofotsy Wetlands during the project
operations phase will be similar to baseline substance concentrations,
due to appreciable dilution of water released from the clarification pond
in the Torotorofotsy basin.
•
Post-closure water quality concentrations in receiving waters for all
basins within the mine area will return to baseline levels after
constructing sustainable reclamation and implementing effective
mitigations.
•
Negligible changes in water and sediment quality will occur in the
Mangoro River due to the relative volume to be pumped from the
Mangoro River to the ore preparation plant and erosion control
measures implemented at the water intake site.
•
Sediment quality in receiving watercourses and water bodies during
mine operations and post-closure will remain similar to observed
baseline levels due to effective erosion control measures, sediment
ponds and sustainable reclamation activities.
•
An assessment of water quality effects on human and ecological health
is provided in Section 5.4 of this volume.
