November 2004 (PDF 11.6 MB) - Barrick Gold Corporation

Table 4.1.Modifying factor corrections(See definitions in Section 4.2)FactorAssessment/measurementWhen to apply Correction 1 CommentsTonal noiseOne-third octaveor narrow bandanalysisLevel of one-third octave bandexceeds the level of theadjacent bands on both sidesby:—5 dB or more if the centrefrequency of the bandcontaining the tone is above400 Hz—8 dB or more if the centrefrequency of the bandcontaining the tone is 160 to400 Hz inclusive—15 dB or more if the centrefrequency of the bandcontaining the tone is below160 Hz5 dB 2 Narrow-bandfrequency analysismay be required toprecisely detectoccurrenceLowfrequencynoiseMeasurement ofC-weighted andA-weighted levelMeasure/assess C- and A-weighted levels over sametime period. Correction to beapplied if the differencebetween the two levels is15 dB or more5 dB 2 C-weighting isdesigned to bemore responsive tolow-frequencynoiseImpulsivenoiseA-weighted fastresponse andimpulseresponseIf difference in A-weightedmaximum noise levels betweenfast response and impulseresponse is greater than 2 dBApplydifference inmeasuredlevels as thecorrection, upto a maximumof 5 dB.Characterised by ashort rise time of35 milliseconds(ms) and decaytime of 1.5 sIntermittentnoiseSubjectivelyassessedLevel varies by more than 5 dB 5 dB Adjustment to beapplied for nighttimeonly.DurationSingle-eventnoise durationmay range from1.5 min to 2.5 hOne event in any 24-hourperiod0 to –20 dB(A) The acceptablenoise level may beincreased by anadjustmentdepending onduration of noise.(See Table 4.2)MaximumadjustmentRefer toindividualmodifyingfactorsWhere two or more modifyingfactors are indicatedMaximumcorrection of10 dB(A) 2(excludingdurationcorrection)Notes:1. Corrections to be added to the measured or predicted levels.2. Where a source emits tonal and low-frequency noise, only one 5-dB correction should be applied if the tone is in thelow-frequency range.NSW industrial noise policy29