| Project Description | WNP Wharekirauponga Underground Mine - Assessment of Effects of Discharges to Air | 4397169-66885702-23 | | 17 Figure 2-5 Typical air vent 2.2.9 Noise earth bunds Noise earth bunds will be formed on the south-eastern boundary of the Surface Facilities Area and further to the east across Willows Rd as shown in Figure 2-1 to attenuate noise at the closest houses. These bunds will be constructed using topsoil excavated from the site. The bunds will be grassed to mitigate dust and visual impact. 2.3 Wastewater Treatment and Disposal Wastewater from staff toilets, showers and canteen facilities will be treated in an MBR (membrane bioreactor) process before discharge to an approximately 2500m2 trench- based disposal area (see location in Figure 2-1). 2.4 Water Supply Water harvested from tunnel dewatering will be piped to the OGNZL water treatment plant at Waihi. Treated water will then be pumped back to WUG for use underground and for surface dust suppression and vehicle washing. Two water tanks are proposed on site, each with a storage capacity of 220m3 (440m3 total). One tank will be installed initially with the second tank installed when operational demand increases. 2.5 Tunnelling Operations Following establishment of the Willows Portal and development of the first tunnel section (Willows Access tunnel) to the base of Vent Raise 1, typical dual-tunnel operations will consist of ● 10-15 firings per week of approximately 4 m in length each ● Digging and loading of the fired rock either directly onto a haul truck or hauling and placing in a stockpile cuddy within 200 m of the face (it is estimated that approximately 825 tonnes per day of rock will be generated)
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