B-2 – Area 2 - Assessment of Environmental Effects 63 These matters have been incorporated into the proposed conditions. 5.7.4 Conclusion The Wharekirauponga Access Tunnel and bussing of mine shift workers to Area 2 will minimise to a significant extent the volume of traffic required to enter and exit Area 2 using Willows Road. However, some light and heavy vehicle movements will still be required for site establishment works, maintenance activities, general mining activities and for staff which work within Area 2. Overall, Stantec (2022) has assessed that the activity can be undertaken in a way that will have acceptable effects on the existing road network in and around the Willows Road area. The Construction Management Plan will seek to manage construction on the public road network, and this process will be utilised for all the road network components of the proposal. Some upgrades to Willows Road and the Willows Road / SH25 intersection are proposed and these will occur within 6 months of construction activities commencing at the site. 5.8 GEOTECHNICAL MATTERS An assessment of geotechnical matters relating to the surface components of the Willows SFA is provided in WSP (2022a). An assessment addressing the Willows Access Tunnel is provided in WSP (2022b). A copy of these assessments is provided in Part H of these application documents. The assessments set out above have completed a review of the ground conditions in which key project elements will be located and have concluded they are suitable from a geotechnical perspective. Tunnel Portal The tunnel portal will be accessed by a road from the mine infrastructure area that will follow the eastern margin of the proposed WRS. It is anticipated that the slope around the portal will require local support by a suitable retaining structure, potentially gravity wall or soil nail/rock bolt reinforced mesh and shotcrete. Such measures will ensure that the access tunnel and portal have a high level of stability. Ventilation Shaft 1 Ventilation Shaft 1 will be approximately 250 m deep and located near the boundary between the Willows SFA site and the CFP. WSP (2022a) considers ventilation shaft 1 will be constructed in andesite rock with strength ranging from very weak to strong and that a bottom-up construction methodology – referred to as an alimak raise would be suitable in
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