November 2004 (PDF 11.6 MB) - Barrick Gold Corporation

Assessing intrusivenessFor assessing intrusiveness, the background noiseneeds to be measured. An objective procedure isoutlined in Section 3.1.The intrusiveness criterion essentially means thatthe equivalent continuous (energy-average) noiselevel of the source should not be more than 5 decibels(dB) above the measured background level.Assessing amenityThe amenity assessment is based on noise criteriaspecific to land use and associated activities. (SeeTable 2.1.) The criteria relate only to industrial-typenoise and do not include road, rail or communitynoise. The existing noise level from industry ismeasured. (See Section 3.2.) If it approaches thecriterion value, then noise levels from new industriesneed to be designed so that the cumulativeeffect does not produce noise levels that wouldsignificantly exceed the criterion. (See Table 2.2.) Forhigh-traffic areas there is a separate amenity criterion(Section 2.2.3). The cumulative effect of noisefrom industrial sources needs to be considered inassessing impact (Section 2.2.4).Project-specific noise levelsFor a particular project, the more stringent of theintrusive or the amenity criteria sets the projectspecificnoise levels for that project. Generally, theintrusive criterion applies for all new industriesuntil an area begins to become more developed,causing increased noise levels. At this stage theamenity criterion starts to take over as the applicablecriterion. Where several new industries areproposed for a new area, care must be taken toensure that equitable levels are set for each proposedindustry (Section 2.2.4).Accounting for annoying noise characteristicsA noise source may exhibit a range of particularcharacteristics that increase annoyance, such astones, impulses, low frequency noise and intermittentnoise. Where this is the case, an adjustment isapplied to the source noise level received at anassessment point before it is compared with theproject-specific noise level to account for the additionalannoyance caused by the particular characteristic.Application of these modifying factors isdescribed in Section 4.Accounting for the effect of meteorology on noiselevelsWhen assessing noise impacts, the project-specificnoise levels are expected to apply under weatherconditions characteristic of an area. These conditionsmay include calm, wind and temperatureinversions. In this regard, the policy addresses theincrease in noise that results from atmospherictemperature inversions and wind effects.The policy sets the following procedure for assessingtemperature inversions (Section 5.2):• an initial screening test is done to identifywhether any further assessment ofmeteorological effects on noise is warranted• where the effect is significant, the proponentmay choose to use default meteorologicalvalues to predict the increased noise levels.These defaults have been provided so thatpotentially costly on-site monitoring can beavoided.• alternatively, the proponent can reject thedefault values and derive parameters bydirect measurement• the increased noise level is then predictedusing the meteorological parametersestablished.This procedure is based on an extensive study of theprevalence of temperature inversions and draws onsubstantial field data.The noise levels predicted under existing meteorologicalconditions for each receiver are then comparedwith the project-specific noise levels, toestablish whether the meteorological effect willcause a significant impact.Wind may also increase noise levels downwind ofthe source. The policy specifies a procedure forassessing the significance of wind effects, and adefault wind speed to be used in the assessmentwhere these effects are found to be significant(Section 5.3).1.4.5 Applying noise mitigation strategiesWhere noise impacts are predicted, noise-sourcemanagers should seek to achieve the criteria byapplying feasible and reasonable mitigation meas-NSW industrial noise policy5