Environmental Assessment
Volume D-3.4
Process Plant
Noise
model methods are 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 are assessed in the fauna section (Volume D,
Section 4.2). Noise predictions provided for the fauna assessment are presented
here for information purposes only.
The effects of traffic on public roadways has been assessed separately in
Volume D, 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
•
a maximum increase in background noise levels of 3 dBA (applied
where background is higher than 55 or 45 dBA respectively).
Criteria are applied at receptors (homes or communities) outside the project
boundary. At the plant site, the boundary is the plant site property boundary.
Residual impacts are determined at specific community receptors based on World
Bank criteria. The parameters used to determine environmental consequence at
the community receptors are direction, magnitude, geographic extent, duration,
reversibility and frequency. The only parameter that has a unique definition for
noise is magnitude. The impact magnitude ratings are also based on the World
Bank (WB) criteria:
•
negligible: predicted noise levels are below the WB criteria and will not
affect baseline noise levels;
•
low: predicted noise levels are below the WB criteria but will increase
period (day or night) baseline noise levels, where baseline levels are
below WB criteria;
•
moderate: predicted noise levels are above the WB nighttime criteria but
below the daytime criteria. Where baseline levels are above WB
criteria, noise levels increase by more than 3 dBA; and
Ambatovy Project
51
January 2006
