November 2004 (PDF 11.6 MB) - Barrick Gold Corporation

• justified any residual impact (that is,remaining exceedances of the project-specificnoise levels after feasible and reasonablemitigation measures have been applied).The noise report showed that noise levels from theexisting premises were well in excess of the applicableproject-specific noise levels at nearby residences,being more than 15 decibels above the projectspecificnoise levels. The report outlined a range ofmitigation measures that could reduce the noiselevels at the site.The mitigation measures involved re-organisingschedules so that noisy activities occurred at lesssensitive times; repair and ongoing maintenance tofaulty bearings; fitting improved mufflers to anumber of pieces of equipment; treating the buildingenvelope by sealing some doorways and windows;erecting a small barrier; enclosing a number ofpieces of equipment; and the possibility of acousticallytreating a residential premises. Even with allthese measures in place it was reported that therewould still be minor exceedances of the projectspecificnoise levels. This was mainly due to theclose proximity of adjoining residential properties.Discussions between the EPA and the companyascertained that it was not economically feasible toimplement all the mitigation measures at once. Itwas agreed to establish a timetable that coveredprogressive mitigation work over time that wouldboth reduce noise levels at nearby receivers andallow the company sufficient time to achieve therequired levels. (For example: re-organise schedulesand repair bearing immediately, seal openingswithin 3 months, replace windows in 6 months andenclose generator in 12 months.)Such a strategy and time-line was then incorporatedinto a pollution reduction program that formalisedthe proposed mitigation works.A5 Urban/industrial interface casestudyThe ‘urban/industrial interface’ receiver category inTable 2.1 may be applied for existing situations onlywhere residences are close to industrial premises.The amenity levels for the ‘urban/industrial interface’category are relevant for a region surroundingthe industrial premises, extending out to a pointwhere a 5-dB reduction in the source noise levelfrom industry is reached. This takes account of hownoise levels are reduced when moving away from asource.In the existing premises example given above, theamenity criteria that would apply would be the‘urban/industrial interface’ criteria if the industrywere in an ‘urban’ area. It would apply for allresidences in a region that extends out from theindustrial boundary to a point where a 5-dB reductionin noise level is reached. This region may bedetermined by measuring the source noise level ateach relevant industrial boundary and then movingback from each respective boundary until the noiselevel has dropped off by 5 dB. For residences beyondthis point the amenity criteria for the ‘urban’category would apply.The following shows a fully worked example usingthe ‘urban/industrial interface’ category.Example:An existing scheduled premises is proposing toupgrade its premises. It operates 24 hours a day,seven days a week. There are residences adjoining itswestern boundary.A noise survey of the area has determined thefollowing existing noise levels at the adjoiningresidences:• rating background levels of 47 dB(A) day,45 dB(A) evening and 40 dB(A) night—determined using the procedure in Section 3.1• existing L Aeq, periodlevels of 52 dB(A) day, 50dB(A) evening and 48 dB(A) night dominatedby the noise from other industry in the area—determined using the procedure in Section 3.2.From Table 2.1, the project fits the description of an‘urban/industrial interface’ receiver type, so therecommended acceptable noise level (ANL) for‘urban/ industrial interface’ area applies (that is,65 dB L Aeq, day, 55 dB L Aeq, eveningand 50 dB L Aeq, night).In this case the existing industrial noise in the area(not including the source in question) is within 6 dBof the ANLs for the evening and night periods, andhence the amenity criteria need to be reduced tocontrol overall levels in the locality to protectamenity, as outlined in Table 2.2.Hence the criteria in Table A5 apply.NSW industrial noise policy66