November 2004 (PDF 11.6 MB) - Barrick Gold Corporation

eing used for a particular project. Where largenumbers of people are likely to be affected by noise,a map showing predicted noise levels as noisecontours surrounding the development is required.6.3 Determining impactsThe noise impact of the development can be determinedby comparing the predicted noise level at thereceiver with the project-specific noise levels thathave been derived for that particular location. Thedevelopment is considered to cause a noise impact ifthe predicted noise level at the receiver exceeds theproject-specific noise levels for the project. Theextent of noise impact from the development isdefined by the extent the predicted noise levelexceeds the project-specific noise levels and thenumber of receivers affected.6.3.1 Impacts under adverse weatherconditionsAs described in Section 5, adverse meteorologicalconditions such as temperature inversions andwinds can act to increase the level of noise receivedfrom a noise source. These meteorological effectsmay also result in increased levels of ambient noisecontributed by industry and background noise.Wind can also reduce noise levels at the receiverwhere it blows from the receiver towards the industry.These effects are site specific and often complex anddifficult to quantify. Extended monitoring and/ordetailed modelling may be needed to capture theeffects or predict what is expected to occur. Thecomplexity and expense involved in quantifying theeffect of adverse meteorological conditions onbackground noise levels or ambient noise levelscontributed by industry preclude these detailedprocedures from being a requirement in assessingnoise impact. However, it is recognised that sucheffects do occur, and these procedures may be usedto assess the effects of meteorological conditions onbackground noise levels and ambient noise levels inthe noise assessment report.assessed under adverse wind conditions (forexample, a 3 m/s wind blowing from source toreceiver), then where a background noise level canbe quantified for those same conditions it is reasonablethat this background noise level should beused to assess impacts under these conditions.In all cases the rating background level should bedetermined (as per Section 3.1) as the starting point,and any adjustments for adverse meteorologicalconditions can then be applied to this base value.Impact should be assessed under both adverse andnon-adverse meteorological conditions to determinethe maximum impact that may occur.Quantifying the influence of temperature inversionson background noise levels can be done in a similarfashion, and the policy provides a number ofmethods for estimating the presence of temperatureinversions.The influence of adverse meteorology on the industrycontribution to ambient L Aeqnoise levels may bemore difficult to establish. However, where this canbe quantified with a reasonable level of confidencethe resultant noise levels may be used in assessingimpact against the criteria.It is emphasised that sufficient objective evidencemust be supplied to support any claim for increasedbackground noise levels or industry contribution tothe ambient L Aeqlevels. It is not sufficient to relysolely on past experience; a site-specific analysis ofthe effects of meteorology must be undertaken.The over-riding objective is to ‘compare like withlike’ and to ensure that the situations where themaximum level of impact is likely to occur areidentified and quantified. For example, where theimpact from a proposed development is to beNSW industrial noise policy37