November 2004 (PDF 11.6 MB) - Barrick Gold Corporation

A2(a)Intrusiveness, amenity and hightrafficcriterion case studiesNew industrial development in a ruralareaA new industrial development is proposed for arural area affected by traffic noise. A noise survey ofthe area reveals a number of nearby residences withthe following background noise levels:• rating background levels of 33 dB(A) day,31 dB(A) evening and 30 dB(A) night—determined using the procedure in Section 3.1.The existing L Aeqlevels were found to be all due totraffic noise and natural sources (there being noother industrial noise sources in the area), so it wasdecided that the existing L Aeqlevel from industrialnoise was negligible. From Table 2.1, the project fitsthe description of a ‘rural’ receiver type, so therecommended acceptable noise level (ANL) for‘rural’ areas applies here (that is, 50 dB(A) day, 45dB(A) evening and 40 dB(A) night). As the existinglevel of noise from industrial sources is negligible,there is no need to reduce the ANL, as outlined inTable 2.2.Hence, the criteria applicable to this project are asshown in Table A2.From the table it can be seen that, if the intrusivenesscriterion is met, the amenity criterion wouldautomatically be met. Hence, the intrusivenesscriterion is the limiting criterion and represents theproject-specific noise levels to be applied to thisproject.Table A2. Criteria applying to casestudy (a)Period Intrusiveness criterion 1 Amenitycriterion 2(b)New industrial development in asuburban areaA new industrial development is proposed for asuburban area. Natural sources and noise fromanother industry in the area dominate the existingnoise levels at the site. Traffic can also be heard atthe site as a very distant hum, with the main roadbeing over 300 m away from the site and shieldedby rows of houses. A noise survey of the area hasdetermined the following existing noise levels:• rating background levels of 51 dB(A) day, 48dB(A) evening and 46 dB(A) night dominatedby the general hum of the industry in the areaand the distant traffic noise—determinedusing the procedure in Section 3.1• existing L Aeq, periodlevels of 57 dB(A) day,54 dB(A) evening and 52 dB(A) night—determined using the procedure in Section 3.2.Note that there was no need to eliminatetraffic noise levels from the measurement, asthey were considered low enough not tocontribute to the levels. (See Section 3.2.1).From Table 2.1, the project fits the description of a‘suburban’ receiver type, so the recommendedacceptable noise level (ANL) for ‘suburban’ areasapplies (that is, 55 dB(A) day, 45 dB(A) evening and40 dB(A) night). In this case, the existing industrialnoise-source level exceeds the ANL, so the ANLneeds to be reduced to control overall levels in thelocality in order to protect amenity, as outlined inTable 2.2. As it is unlikely that existing noise levelswill decrease in future, the criterion that applieshere is ‘existing level minus 10’.Hence the criteria shown in Table A3 apply to thisproject.Table A3. Criteria applying to casestudy (b)Day 38 dB L Aeq,15 minute(33 + 5) 50 L Aeq,DayEvening 36 dB L Aeq,15 minute(31 + 5) 45 L Aeq,EvenPeriodIntrusivenesscriterion 1Amenitycriterion 2Night 35 dB L Aeq,15 minute(30 + 5) 40 L Aeq,NightNotes:1. Intrusiveness criterion is L Aeq,15 minute≤ RBL + 5(Section 2.1)2. Amenity criterion for rural areas (Tables 2.1 and 2.2,Section 2.2)Day 56 dB L Aeq,15 minute(51+ 5) 47 L Aeq,DayEvening 53 dB L Aeq,15 minute(48 + 5) 44 L Aeq,EvenNight 51 dB L Aeq,15 minute(46 + 5) 42 L Aeq,NightNotes:1. Intrusiveness criterion is L Aeq,15 minute≤ RBL + 5(Section 2.1)2. Amenity criterion for suburban areas (Tables 2.1and 2.2, Section 2.2)NSW industrial noise policy62