November 2004 (PDF 11.6 MB) - Barrick Gold Corporation

activities, they also increase environmental noiselevels. Therefore, previously low ambient noiselevels will not be maintained, and assessments ofnoise sources for control purposes should be madeagainst the acceptable noise level relevant to themodified land use.2.3 Using the L AeqdescriptorThe L Aeq,descriptor applies for both the intrusivenesscriterion (L Aeq, 15 minute) and the amenity criterion(L Aeq, period). In this policy, the equivalent continuous(energy average) level (A-weighted) of the industrialsource is of interest (not necessarily that of the totalnoise environment). In certain circumstances othernoise descriptors may be more appropriate formeasurement/assessment or compliance purposes,depending on the characteristics of the noise source.For example, where the noise emissions from thesource of interest are constant (e.g. fan noise) andthe ambient noise level has a degree of variability(for example, due to traffic), the L A90descriptor mayadequately describe the noise source and be mucheasier to measure/assess. In these cases, it may bepreferable to replace the L Aeqdescriptor.If the descriptor chosen for measurement is not theL Aeq, reasons for the variation should be presentedin the noise assessment report.2.4 Project-specific noise levelsAfter determining the relevant noise levels from theintrusive and amenity criteria, the project-specificnoise levels can be assigned.The project-specific noise levels reflect the moststringent noise level requirement from the noiselevels derived from both the intrusive and amenitycriteria. They set the benchmark against whichnoise impacts and the need for noise mitigation areassessed.Applying the most stringent requirement as theproject-specific noise levels ensures that bothintrusive noise is limited and amenity is protected.The case studies presented in Appendix A showdefinitively how project-specific noise levels areidentified.NSW industrial noise policy21