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 22 of 79 4.2 Recommended Operational Noise Limits 4.2.1 The District Plan limits are appropriate for activities undertaken as part of the WNP project for all zones (except the conservation area). The District Plan Noise limits provide a clear and consistent indication of anticipated amenity in the residential zone, and in rural residential settings – all of the rules listed in Table 1 refer to a daytime noise limit of 50 dB LAeq and night-time noise limits of 40 dB LAeq and 65 dB LAmax (at the boundary or notional boundaries of dwellings). These values provide for a relatively high level of amenity in a rural area, where noise limits of 55 and 45 dB LAeq (for day and night, respectively) are not uncommon in other District Plans. These higher values are also consistent with the upper range of other guidance commonly used in New Zealand, including that in NZS 6802 and the WHO Guidelines discussed above. As such, we expect that the District Plan noise limits will provide an appropriate degree of protection for local receivers of noise. In addition, noise effects can be disregarded at dwellings owned by, or that have an agreement with OGNZL and therefore the noise limits would not apply. Based on the above and Sections 2 and 3, and to harmonise the way noise is managed from the Waihi North mining operations, and to ensure general consistency with the District Plan, we recommend operational noise criteria below apply across all parts of the Waihi North Project. This would mean these would become conditions attached to the resource consents. We do however recommend a higher LAmax noise limit at night. This is because the District Plan LAmax limit is unusually strict (65 dB LAmax) and based on the existing noise environment a higher noise limit is appropriate. This is also consistent with the guidance contained within NZS 6802. The recommended condition is given below All activities associated with WNP shall not exceed the following limits when measured at or within the boundary of any residentially zoned site or the notional boundary of any occupied dwelling in the Rural Zone not owned by POGNZL or where there is an agreement in place with OGNZL andmeasured over the periods specified below: 0700 - 2200, Monday to Saturday 50 dB LAeq All other times 40 dB LAeq 2200 - 0700 (the following day) 70 dB LAFmax When viewing the combined construction noise and operational noise exposure for residents over the life of the WNP, we consider it desirable to limit the total operational noise exposure on residents by not allowing noise at the upper limits of acceptability for normal operations, as referenced in NZS 6802 (being 55 dB LAeq). This is reflected in our proposed noise limits above being 5 dB more stringent. 4.2.2 There are no specific protections for recreational users of the conservation area affected by WUG The District Plan noise standards within the Conservation (Indigenous Forest) Zone only apply at designated campsites. The closest site is the Wentworth Valley Campground, which is approximately 6 km north of the WUG orebody and 12 km north-west of the Willows Portal site. Although there are few established walking tracks, we understand that the area is used for recreational activities such as hunting. While no specific protections apply, the noise monitoring we have undertaken allows us to better understand the potential effect on these users. This is discussed further Section 9.4. Based on measurements of noise levels in conservation areas we have undertaken elsewhere (medium to dense native bush), and with reference to the measured noise levels in the conservation area (refer Section 3.3), the background noise levels are 20 – 40 dB LA90. In the vicinity of watercourses (streams, rivers etc.) the background noise level may be 10 – 20 dB higher. Therefore, where the ventilation raises are proposed to be located, the existing ambient noise levels are likely to be very low, comprising natural sounds (wind in trees, birdsong, streams etc.), with negligible noise from human activity. It is important to note that noise levels may vary, with variation due to local sources such as streams, roads and shielding provided by terrain.
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