November 2004 (PDF 11.6 MB) - Barrick Gold Corporation

Appendix B—Applying the background noise policyB1Long-term background noisemethodThe long-term background noise measurementprocedure should be used during the planning andconsent stage for developments that have thepotential to cause significant noise nuisance. Boththe type of development and its proximity to noisesensitivelocations are important elements to beconsidered in deciding whether the long-termmethod is the most appropriate.Some examples of developments that may present ahigh risk of noise impact include:• extractive industries (for example, mines andquarries)• industrial developments (for example,bitumen plants, coal works, crushing andgrinding works, drum re-conditioning, powerstations, refineries and timber mills)Essentially, the procedure for determining long-termbackground noise involves two components:1. determining a representative backgroundnoise level for each day/evening/night of themonitoring period. This level is termed theassessment background level (ABL), and is asingle figure representing each day/evening/night for each monitoring site required for aparticular project.2. determining an overall level representing theday, evening and night assessment periodsover the entire monitoring period. This levelis termed the rating background level (RBL),and is determined based on the individualday/evening/night ABLs as outlined inSection B1.3.The rating background levels are used in determiningthe intrusiveness criterion.B1.1 Instrumentation requirements andsitingBackground noise levels should be measured with anoise data logger that has an accuracy at leastequivalent to the specifications of a Type 2 meter asstated in AS 1259. The data logger should be fittedwith a windshield and should have a currentlaboratory calibration certificate or label in accordancewith calibration requirements outlined inAS1259 and AS2659. Equipment should also becalibrated in the field in accordance with thesestandards.Site the data logger(s) at the most- (or potentiallymost-) affected noise-sensitive location(s). If this isimpractical, site the logger(s) at locations with asimilar acoustical environment. Be careful to choosesites that are truly representative of the noiseenvironment at the noise-sensitive receivers—forexample, do not choose positions screened fromdominant background noise sources such as roadtraffic if sensitive receivers are not screened fromsuch sources. Locate the microphone 1.2 to 1.5 mabove the ground and, where practicable, at least 3to 5 m from walls, buildings and other reflectingsurfaces. Data loggers should be sited as far awayfrom trees as practicable to avoid noise producedby wind blowing through foliage.During monitoring, set the meter to ‘Fast’ timeweighting and ‘A’ frequency weighting.A weather monitor that continuously monitorswind and rainfall data should be positioned within5 m of the data logging equipment—ideally, in aplace that is not shielded from the wind. The effectof weather on the instrumentation is of interest here,so the height of the monitor should correspond tothat of the noise logging equipment. Where multiplemonitoring sites are required for a particular project,it is best to have simultaneous weather monitoringat each noise logger location. However, weatherconditions may be represented by a single weathermonitor, provided this is within a 30-km radius ofthe site and in the same topographical basin. Theweather monitor should record average wind speed(accuracy to within ± 0.5 m/s) at least once every 15minutes (corresponding to the noise measurementinterval) and record the time intervals of rainfall.Monitoring should not be conducted (or monitoringdata are to be excluded) when average wind speedsare greater than 5 m/s or during rain. Exceptions tothis rule are allowed, provided the proponent isNSW industrial noise policy68