November 2004 (PDF 11.6 MB) - Barrick Gold Corporation

In this case, the amenity criterion is the limitingcriterion and represents the project-specific noiselevels to be applied to this project.(c)New industrial development in ahigh-traffic areaA new industrial development is proposed on amajor highway. The noise environment at thenearest affected residences is dominated by trafficnoise from the major highway. There are otherindustries in the area, but they cannot be heardabove the traffic noise. A noise survey of the areahas determined the following existing noise levels:• rating background levels of 58 dB(A) day,58 dB(A) evening and 44 dB(A) nightdominated by traffic noise—determinedusing the procedure in Section 3.1• existing L Aeq, periodlevels of 70 dB(A) day,69 dB(A) evening and 66 dB(A) night—determined using the procedure in Section3.2. Note that these levels were solely due totraffic.Note: From an initial survey of the area anddrawing on local knowledge, it was foreseen at thestart of monitoring that existing traffic noise levelswould be well over 10 dB above the ANL for thearea (‘urban’ category—60 dB(A) day, 50 dB(A)evening, 45 dB(A) night). Hence, based on Section2.2.3, there was no need to eliminate traffic noiselevels from the measurement, as the high-trafficamenity criterion depends on the existing trafficnoise level only. (If traffic noise levels had been lessthan 10 dB above the ANL, then one of the methodsin Section 3.2.1 could have been employed to excludethe traffic noise level.)As the existing traffic noise levels are 10 dB or moreabove the ANL for the area, the high-traffic amenitycriterion applies to this project. This is stated as‘L Aeq,period≤ L Aeq, period(traffic)–10’ from Section 2.2.3.Hence, the criteria that apply to this project are asshown in Table A4.In this case the high traffic amenity criterion is thelimiting criterion for the day and evening periods,and the intrusiveness criterion is the limitingcriterion for the night period. The project-specificnoise levels for this project comprise each of these.Table A4. Criteria applying to casestudy (c)PeriodDayEveningNightA3(a)Meteorological-enhancement casestudiesArea affected by temperatureinversionsFor proposed developments that operate at night, theeffects of temperature inversions need to be considered.For case study (a) in the previous section, theassessment of noise enhancement (increase) causedby temperature inversions is as follows (using theprocedure outlined in Appendix C).Screening testsIntrusivenesscriterion 163 dB L Aeq, 15 minute(58 + 5)63 dB L Aeq, 15 minute(58 + 5)49 dB L Aeq, 15 minute44 + 5)High trafficamenitycriterion 260 dB L Aeq,Day(70 –10)59 dB L Aeq, Even(69 –10)56 dB L Aeq, Night(66 –10)Notes:1. Intrusiveness criterion is L Aeq,15 minute≤ RBL + 5(Section 2.1)2. High traffic amenity criterion (Section 2.2.3)Test 1. As the development will be operational 24hours a day, the potential for noise increase resultingfrom temperature inversions warrants furtherinvestigation.Test 2. An initial check to determine whether thisincrease in noise will have an impact on residents inthe area is done, using default parameters in thenoise prediction to estimate the upper level ofimpact. For a non-arid area a temperature inversionstrength of 3 °C/100 m applies, and for residentsdownhill from the source a drainage-wind-flowwind speed of 2 m/s also applies. (The screeningtest for non-arid areas assumes the presence of an F-class stability, as this category is much more likely tooccur in these areas than G-class). An inspection ofthe area reveals that residences are located between500 and 1000 m away from the source in a downhilldirection. Using the table in Appendix D, the noiseincrease due to inversions is between 4 dB and 5 dB.Where this increase results in exceedance of theNSW industrial noise policy63