| Project Description | Waihi North Project Air Discharge Assessment - Waihi Surface Facilities | 4396626-1331619777-99 | 16/06/2022 | 11 Explosive charge up units 1 1 Dozers 1 2 Graders 1 1 Service vehicles 2 2 Water cart 1 2 Light vehicles 6 7 Compactor 1 1 2.3 Rock and Tailings Storage 2.3.1 Introduction The WNP will require the construction of new tailings facilities (TSF3 and GOP TSF) and a new permanent overburden repository to be known as the Northern Rock Stack (NRS). 2.3.2 Tailings storage facilities (TSFs) a. TSF3 TSF3 will be a downstream earth and rockfill embankment dam, like TSF1A and 2, to store discharged slurry from the Processing Plant. The total footprint of works required for TSF3 is approximately 115 ha. The area includes the stockpile areas, the new embankment and impoundment area, collection ponds, the uphill diversion drain and the area between the impound and uphill diversion drain. Approximately 80 ha of topsoil and subsoil will be progressively stripped from the area. Stripping will be undertaken in stages as required. Vegetation will also be removed from approximately 7.0 ha4. It is expected the vegetation will be mulched on site, and then taken to the smaller west and east stockpiles. The extent of the topsoil stripping and the location of the topsoil and vegetation stockpiles are shown in Figure 2-3. Approximately 1.5 to 2 Mm3 of soil and weathered rock will need to be removed from the TSF impoundment area and stockpile areas during construction. Some of this material will be placed in the stockpile and some worked into the embankment. The TSF3 impoundment embankment will be raised in stages to a final height of 155 mRL (mine datum). Construction of the starter embankment (135 mRL) will take approximately three years to complete. The facility, when raised to 155 mRL, will have the capacity to contain approximately 5,700,000 m3 of tailings storage. Figure 2-4 is a conceptual plan showing TSF3 at completion and the associated stockpiles to the south-east. b. GOP TSF Once mining of the GOP has ceased, the pit will be partially backfilled and converted to a tailings storage facility (i.e. GOP TSF). The conversion of the pit to a TSF is expected to take approximately two years to complete. Approximately 5.0Mt of suitable rock will be required for the construction of the GOP TSF. The rock for backfilling will be transported from the NRS by reversing the existing mainland conveyor. It is expected that rock will be placed by paddock dumping and then compacted in place by a dozer and mobile compacter. Once the base layer is formed and covered with a geomembrane liner, tailings from the Processing Plant will be deposited within the pit over approximately a four-year period. The pit will store approximately 2.1 Mt of tailings with a final level of approximately 1103 mRL. 4 Approximately 5.7 ha in the Significant Natural Area (SNA) and 1.3 ha outside the SNA
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