November 2004 (PDF 11.6 MB) - Barrick Gold Corporation

Table C2. Procedure for assessing meteorological effectsAlternatives forassessment1. Use existingdata todeterminemeteorologicalnoise impactrelevant to theareaProcedureAnalyse site-specific meteorological data using one of the four existing data methodsdetailed in Table C4 to determine the percentage occurrence of atmospheric stabilitycategory F 1 or G 2 temperature inversions.If the frequency of temperature inversions during the winter months is less than 30per cent of the total night-time (for inversions this is from 1 hour before sunset to 1hour after sunrise, taken to be 6 pm to 7 am), these effects are not consideredsignificant and no additional noise predictions are needed.If temperature inversions occur for 30 per cent of the total night-time or more during thewinter months, adopt the following default values to predict noise impact:Where rainfall ≥ 500 mm/yearF-class inversions• inversion: 3°C/100 m• source-to-receiver drainage-wind speed where applicable 3 : 2 m/s at 10 mheight2. Use actualmeasurementsto determinemeteorologicalnoise impactrelevant to theareaG-class inversions• inversion: 4°C/100 m• source-to-receiver drainage-wind speed where applicable 3 : 3 m/s at 10 mheightWhere rainfall < 500 mm/yearG-class inversion• inversion 8°C/100 m• source-to-receiver drainage-wind speed where applicable 3 : 1 m/s at 10 mheightApply the above meteorological parameters to the noise prediction and determine theincreased noise level.Compare the final predicted level with the project-specific noise levels to assess the noiseimpact.If the default temperature inversion and wind drift parameters are not acceptable to thedeveloper, the actual temperature inversion strength and wind speed may be measured.(See Alternative 2 below.)Measure the actual temperature inversion strength and wind speed using the ‘Directmeasurement of temperature lapse rate’ method outlined in Table C4.Use these measurements to predict noise levels and compare the prediction with theproject-specific noise levels to assess the noise impact.Notes:1. F-class stability category corresponds to moderate inversions.2. G-class stability category corresponds to strong inversions.3. The drainage-flow wind default value should generally be applied where a development is at a higheraltitude than a residential receiver, with no intervening higher ground (for example, hills).NSW industrial noise policy74