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 65 of 79 C5 Noise Level Analysis The table below shows the noise levels at the north-western receivers for the year 2024. Overall noise levels are similar in 2025 and 2026. These calculations assume use of the smaller 51 tonne loader as discussed above for the baseline (i.e. non-mitigated) scenario, and a 3 metre wall at Barrier C. Table 19: 2024 noise emissions to north-west, with Barriers A-C and source management options Receiver Noise level with no mitigation, dB LAeq Dominant noise sources Noise level with mitigation, dB LAeq Quieter plant A only (Fence) B only (Bund) C only (N wall) A+B A+B+C All 55 Barry Rd 51.4 Processing (45 dBA) GOP FEL (44 dBA) 180t Excv. (43 dBA) 777 Haul (42 dBA) GOP Crush (40 dBA) 50.8 51.4 51.3 50.6 51.3 50.6 50.0 72 Barry Rd 53.9 180t Excv. (47 dBA) GOP FEL (47 dBA) 777 Haul (44 dBA) Processing (43 dBA) GOP Crush (43 dBA) 52.6 51.9 52.6 53.1 51.9 51.8 50.3 10 Moore St 53.0 180t Excv. (46 dBA), Processing (46 dBA) GOP FEL (44 dBA) 777 Haul (41 dBA) GOP Crush (42 dBA) 51.7 53.0 51.2 52.4 51.2 51.1 49.5 Table 20: Noise levels at 33A Heath Road for years 2024-2026, with Barrier D and source management options Year Noise level with no mitigation, dB LAeq Dominant noise sources Noise level with mitigation, dB LAeq Quieter plant SW Pit Wall Both 2024 51 180t Excv. (44 dBA) 777 Haul (43 dBA) 50t Excv. (43 dBA) 65t Dozer (40 dBA) 50 N/A 50 2025 54 777 Haul (50 dBA) 40t ADT’s (48 dBA) Drills (45 dBA) Water cart (41 dBA) 54 49 49 2026 53 180t Excv.’s (49 dBA) GOP crusher (44 dBA) 777 Haul (43 dBA) 40t ADT’s (40 dBA) 53 51 51 C6 Outcomes Northern Barriers The results opposite indicate that the range of mitigation options available generally all achieve the same result when used in isolation. Barriers A and B only provide any benefit to the houses immediately behind them. In general, Barrier A benefits 72 Barry Road, Barrier B benefits 10 Moore Street and Barrier C benefits 55 Barry Road. In all cases the benefits are small to the extent of being imperceptible. From the discussions we have held, we understand the use of quieter plant may render the project unfeasible, and would almost certainly extend the duration of mining, meaning it is not considered further. With this in mind, the best acoustical outcome would be the construction of barriers A, B and C. Notwithstanding this, we note that these barriers still do not ensure noise levels are below 50 dB, only offer an imperceptible improvement and may have other adverse effects (such as visual). Therefore, alternative mitigation in the form of building mitigation has been considered. Southern Barrier With respect to Barrier D in the south-west, we understand from discussions with OGNZL that in practice this would be a difficult barrier to construct. On top of this, the construction of the barrier itself would give rise to construction noise emissions. While it would not be impossible to construct, we note also it is only effective for year 2024 with insignificant benefits in later years. For these reasons, this barrier is discounted. The implications of this however are that noise levels at this dwelling are in excess of the criteria for some operational scenarios. In addition, we have also investigated localised screening around 33A Heath Street, such as a double-height container barrier on the property boundary. As well as being intrusive visually for that property, it also does not achieve any appreciable noise reduction. This is therefore discounted as being an option. Therefore alternative mitigation in the form of building mitigation has been considered. C7 Building Mitigation Consideration can also be given to offering building mitigation to these dwellings to enable acceptable indoor noise levels. We expect this would consist of provision of a mechanical ventilation system so that windows and doors can remain closed. Whilst not ideal, it goes some way to mitigating noise effects and would in our opinion maintain the existing amenity for these residents. This is broadly consistent with the approach adopted for large infrastructure projects, such as roads, ports and airports.
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