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 27 of 79 6.2 Construction Activities 6.2.1 Gladstone Hill As described in Table 6, a number of construction activities will be necessary to establish this worksite. The most significant in terms of noise experienced outside the MMZ are expected to be initial works on the hill, including topsoil stripping and removal of overburden, and construction of the MUG Portal with initial sections of the underground drives. The WUG Portal activity is described further in Section 6.2.2. The initial phase of preparation will require earthworks plant to operate on the top of Gladstone Hill, where it will effectively be exposed to receivers on all sides. Noise emissions will, however, be somewhat limited in that only relatively small equipment can be used during this phase of operation, as the hill could not support the bulk of the large 180 tonne excavator, for example. Figure 13 shows noise contours from example construction works occurring on top of the hill. This assumes a scenario with multiple excavators (up to five, 20t - 50t), bulldozers (up to three, 20t - 50t) and articulated dump truck movements. The calculations show that noise levels will be around 45 dB LAeq at the closest dwellings. Following these works to establish the site, the initial mining preparation will take place to form the pit and other ancillary features. For receivers of noise outside of the site, this phase will generally be a transition from construction noise to operational noise. However, in terms of how this is assessed from a technical perspective, it marks a shift from noise being assessed under the construction noise standard (NZS 6803) to being assessed under the project’s operational noise limits. We expect that this transition will occur approximately mid-2024, when the new GOP crusher becomes operational. Larger mining equipment will also be utilised by this time. Noise-generating activities from then on will be typical of ongoing operations, so it is most appropriate to assess against the operational noise limits. Figure 13: Noise contours from Gladstone Hill construction activities 6.2.2 WUG Portal A new portal will be constructed for the proposed materials handling tunnel to connect the WUG mine with the main site in Waihi. This will allow for transfer of ore to the Processing Plant and if needed, backfill material from the NRS. This portion of the project will also allow for the future development of a new portal to Martha Underground Mine. We understand that the portal will be achieved through a significant cutback to the Silverton Hill, beneath the company-owned dwelling at 23 Boyd Street. This cut will bring the ground level down to form a plateau around the same elevation as the polishing ponds area. As previously, the initial earthworks at the top of the existing hill will be the most exposed to northern receivers. We have calculated likely noise levels based on excavators, bulldozers and dump trucks working in this area, with the results shown in Table 11 and Figure 14 below. Figure 14: Noise contours fromWUG Portal construction activities Calculated noise levels at select receiver locations are given below. Compliance is achieved at all locations. Table 11: Construction noise levels around Gladstone Hill and the WUG Portal at select receivers Receiver Calculated noise level, dB LAeq Gladstone Hill Construction WUG Portal Construction R11 – 55 Barry Road 45 43 R12 – 10 Moore Street 48 44 R13 – 72 Barry Road 45 47 R15 – 107 Barry Road 31 42 R16 – 33A Heath Road 34 44
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