Environmental Assessment
Volume B-3.9
Mine
Water Quality
Ambatovy Project
119
January 2006
•
diversion and disruption of natural drainages;
•
metal leaching from waste rock and ore stock piles;
•
seepage from the mine area;
•
runoff releases from the collection and clarification ponds used to
manage water from the mine areas;
•
accidental releases and spills; and
•
site closure and reclamation activities.
The linkages between project activities and effects on water and sediment quality
are given in Volume H, Appendix 9. Potential water and sediment quality effects
can occur during all phases of the project, including construction, operations and
post-closure.
The key question for water and sediment quality is:
Key Question SWQ-1 What Effect Will the Mine Have on Water and
Sediment Quality?
3.9.5
Impact Assessment
The proposed mine area is located within a drainage divide of six water basins,
including the Antsahalava, Sahaviara, Torotorofotsy, Sakalava, Sahamarirana
and Ankaja rivers. The Antsahalava, Sahaviara and Sahamarirana basins drain
the Ambatovy ore area, while the Torotorofotsy, Sakalava and Ankaja basins
drain the Analamay ore area.
Collection and clarification ponds will be located in each of the six basins to
collect and reduce sediments carried by runoff from areas affected by the mine.
In each basin, water will be routed through the collection pond and then a
clarification pond before it is released to the receiving watercourses and water
bodies. The runoff may originate from undisturbed areas, mined areas, waste
stock pile areas or other disturbed areas (i.e., roads and buildings) within the
mine area. However, highly affected active pit sump water will be preferentially
routed to the ore preparation plant. The sub-basins associated with various
downstream distances are shown in the Hydrology Section (Volume B,
Figure 3.8-1).
