Environmental Assessment
Volume C-3.4
Slurry Pipeline
Noise
Ambatovy Project
38
January 2006
of average is commonly used in an environmental (outdoor) context as it takes
into account natural variations in sound.
The qualitative assessment of changes in noise levels for the slurry pipeline was
accomplished by:
•
establishing baseline noise levels at potential receptors;
•
determining the amount of sound generated by construction activity; and
•
calculating the distance required from project-related noise that would
experience noise levels over the World Bank criteria.
Activities or equipment that have sound emissions were determined based on
information contained in the project description (Volume C, Section 2) and
client-supplied equipment lists. Sound emissions for the various sources were
based on noise measurements from similar equipment, manufacturer data or
standard sound emission formulae.
Calculations were conducted using formulae consistent with International
Standardization Organization (ISO) acoustic standards and World Bank criteria,
providing L
eq
noise levels over selected time periods.
The effects of noise on wildlife have been addressed in the fauna impact
assessement section. Noise predictions provided for the wildlife assessment are
presented here for information purposes only.
The effects of traffic on public roadways has been assessed separately in
Volume C, Section 5.5.
3.4.4.3 Residual Impact Criteria
Criteria used for noise are the World Bank noise standards for mining activity:
•
an hourly L
eq
noise level of 55 dBA between 7:00 am and 10:00 pm
(daytime);
•
an hourly L
eq
noise level of 45 dBA between 10:00 pm and 7:00 am
(nighttime); and
•
where background noise is higher than 55 or 45 dBA respectively, a
maximum increase in background levels of 3 dBA.
