Environmental Assessment
Volume B-3.7
Mine
Hydrogeology
Ambatovy Project
84
January 2006
Nickel concentrations in groundwater appear to exceed the WHO provisional
guideline for drinking water quality, ranging from 0.05 to 0.74 mg/L compared
with the WHO provisional guideline of 0.02 mg/L. The exception is the Korean
Pit, where nickel was <0.003 mg/L, below the WHO provisional guideline.
The WHO guideline for nickel is provisional because of the lack of information
on health effects. The US EPA maximum level for drinking water is 0.1 mg/L
and a guideline level for the Canadian Drinking Water Quality Guidelines is
under preparation (Water Quality Section, Section 3.9 of this volume).
3.7.4
Issue Scoping
The main potential issues relating to hydrogeology are:
•
changes to the groundwater system (flow and quality) due to dewatering
of the open pits during mining; and
•
effects the changes to the groundwater system may have over the long
term to people or the environment.
Depending on the amount of terrain recontouring at the time of reclamation, local
changes in topography may have implications for hydrogeology.
The Key Questions for the hydrogeology surrounding the mine are:
Key Question HG-1
What Effect Will the Mine Have on Groundwater
Flows and Quality at the Mine Site?
Key Question HG-2
What Effect Will the Mine Have on Groundwater
Flows and Quality at the Surrounding Area,
particularly the Torotorofotsy Wetlands?
3.7.5
Impact Assessment
Project activities during construction, operations and closure will result in the
following: i) localized dewatering of groundwater aquifers around the mine site;
ii) changes in groundwater quality; and iii) subsequent effects on the hydrology
of the Torotorofotsy Wetlands.
During construction there will be little impact on groundwater resource, as
disturbance to the landscape primarily involves site clearing and the development
of infrastructure. Mine runoff collection ponds will be constructed and surface
