Environmental Assessment
Volume B-3.1
Mine
Topography and Geomorphology
Ambatovy Project
19
January 2006
The existing topography of the mine LSA is hilly with relatively steep slopes,
except at the western end of the water intake pipeline corridor and in the
immediate vicinity of the Torotorofotsy Wetlands. The areas affected by
topographic change due to mining include plateau areas, steep valleys and ridges
with slopes ranging from flat to about 45 degrees.
Table 3.1-2 Potential Effects and Residual Impacts for Topography and
Geomorphology
Project
Period
Potential Effects
Mitigation
Residual Impacts
construction changes in the landscape and underlying
geomorphology slope during short-term
construction
erosion control;
water
management;
stable slope
engineering
low magnitude/short-term
modification of ore bodies
and adjacent topography
operations
removal and disturbance of important
topographic features important for social
or biological reasons (ore body
formations)
changes in the landscape and underlying
geomorphology slope which may
represent important issues over the
medium term to stakeholders and
biodiversity
erosion control;
water
management;
stable slope
engineering;
progressive
reclamation
moderate magnitude /
medium-term modification of
ore bodies and adjacent
topography
closure
changes in the landscape and underlying
geomorphology slope which may
represent important issues over the long
term to stakeholders and biodiversity
erosion control;
water
management;
stable slope
engineering;
full reclamation
low magnitude / long-term
modification of ore bodies
and adjacent topography
Mining activity will have a direct impact on the landscape and underlying
geomorphology within the ore body areas, with the creation of open pits, waste
areas and a pond system. Some impacts will be temporary (medium-term),
because temporary stockpiles will be removed and some pit areas will be
backfilled during the operations and closure phases. Other impacts are long-
term, because mine landscape features different than the baseline landscape will
remain beyond the closure phase.
The magnitude of the changes are considered low during construction, as
relatively small areas will be altered during this period. The magnitude of
changes are considered moderate during operations, because changes in
topography are greatest during the operation of pits and the maximum sizes of
stockpiles occur during this period. The magnitude of the change following
