This document may not be reproduced in full or in part without the written consent of Marshall Day Acoustics Limited Rp 001 R0 20210601 SJP (Waihi North Noise Assessment) ISSUE 43 of 79 9.4 Predicted Helicopter Noise Levels Predicted helicopter noise levels are shown in Figure 28 opposite, which gives both the calculated LAeq (15min) and LAFmax noise levels. We have only presented in detail noise from helicopters accessing typical ventilation raise sites, but the assessment and conclusions would be valid for any remote sites associated with the project where helicopters are to be used. 9.4.1 Rural Zone Because the helicopters operate to and from the ventilation raise construction sites, they only pass houses for a short period of time in transit. The maximum noise levels received at these dwellings are comfortably below 70 dB LAFmax at the notional boundary of all dwellings. This means they are significantly lower than the construction criteria of 90 dB LAFmax. 9.4.2 Conservation Area We consider that helicopter noise levels are likely to be at elevated levels only in close proximity to the raise sites, and not across the conservation area as a whole, and noise would be fairly regular in nature during each helicopter campaign. As shown on Figure 25 and by way of comparison, the construction noise criteria of 75 dB LAeq (15mins) is emitted only relatively close to construction activity. We expect that for users of the Wharekirauponga Track, noise would be clearly audible if they are at the midpoint of the track closest to the raise sites, but based on the number of users it is likely only for a very small number of people. We note that noise levels from individual helicopter operations would still likely be audible more widely across the conservation area. However, these events would be at such low noise levels, for only a brief duration and for only a small number of events per campaign. In our opinion this means that helicopter noise impacts on users of the conservation area are not significant. Overall, in terms of recreational users of the conservation area, we therefore consider that helicopter operations would have acceptable effects. To adopt BPO, some methods to reduce helicopter noise effects would be to limit the number of flights or to time flights when recreational use is lower (during the weekdays, or winter) however we consider specific mitigation is not necessary in this case. Figure 28: Calculated helicopter noise levels associated with construction of vent raise sites
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