Environmental Assessment
Volume E-3.1
Tailings Facility
Topography and Geomorphology
Ambatovy Project
22
January 2006
3.1.5.4 Results
Three valleys will be affected by the project. Over the course of construction and
operations, a variety of landscape features including dams, linear access routes,
drainage ditches and a flattened surface of the tailings pond will be developed,
altering local topography.
Initial embankments for the tailings area will be constructed with slopes of
2H:1V (27 degrees). For on-going raises the downstream slope will be 3H:1V
(18 degrees) to maintain stability. The surface of the tailings facility will evolve
over time during the operations phase with the development of beaches in each
area where tailings are fed into the pond. At the time of reclamation, the tailings
pond surface is expected to be relatively flat.
3.1.5.5 Impact Analysis
Residual Impacts
Following mitigation, the residual effects during each project period are
summarized in Table 3.1-2.
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
slopes during short-term
construction
erosion control;
water management;
stable slope
engineering
moderate magnitude/short-term
modification of tailings facility
dams, tailings facility access route
and adjacent topography
operations
changes in the landscape and
slopes 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
tailings facility dams, tailings
facility surface area and adjacent
topography
closure
changes in the landscape and
slopes which may represent
important issues over the long
term to stakeholders and
biodiversity
erosion control;
water management;
stable slope
engineering;
full reclamation and
recontouring of
pond surface area
moderate magnitude / long-term
modification of tailings facility area
