Environmental Assessment
Volume C-3.5
Slurry Pipeline
Natural Risks
Ambatovy Project
46
January 2006
Water Erosion
Risk mitigations planned for the detailed engineering phase of the project
include:
•
a detailed survey of the pipeline route including geotechnical data;
•
a hydrological survey of the region; and
•
design features for river crossings to “armour” the pipeline against
damage include:
−
The calculated minimum burial depth (buried crossings) is
maintained through the entire waterway floodplain to allow for
shifting of the river path within the plain.
−
Buried crossings will be concrete-coated to prevent mechanical
damage to the pipe if the waterway bed is shifting.
−
Extra pipe wall thickness will be added at crossings. The extra
thickness will be maintained through the entire waterway floodplain.
−
Erosion control will be constructed for aerial span supports and at
banks near the crossing to add localized protection.
Seismic Hazards
During detailed engineering a complete geotechnical survey will be completed to
assess seismic activity along the right-of-way and identify fault crossings and
potential liquefaction zones.
In general, a buried pipeline is not impacted by an earthquake. The pipe has
adequate flexibility to move with the earth except at fault crossings where special
designs are incorporated to mitigate the effects.
The pipeline will be routed around all areas of potential liquefaction. If an area
can not be avoided, friction piles will likely be installed under the pipeline. This
piling provides support if the soil cannot because it is liquefied during an
earthquake.
In addition to prevention measures, a primary method to mitigate the impact of
any pipeline leak is early detection and implementation of emergency response.
The slurry pipeline will be monitored by a Supervisory Control and Data
Acquisition (SCADA) leak detection system that will detect any system leaks
and predict their location as well as issue warnings to operators.
