June 2022 G-14642.71-006-R-Rev0_FINAL 31 8.0 WAIHI ACCESS TUNNEL The Waihi access tunnel provides underground access from the plant site at Waihi to the end of the twin tunnels at Vent Shaft 1, a distance of about 5 km. The objective of the Waihi access tunnel is to provide a direct underground route for ore between the WUG underground mine and the ore processing plant. 8.1 Proposed Portal The proposed portal location for the Waihi to Willows (Figure 17) access tunnel is a new, as yet unformed, cutback north of the proposed Gladstone Pit. The proposed cutback will create a level platform at about RL1110 m with cut slopes formed on the north and west side of the platform. The cutback slopes will be up to about 30 m in height with an overall slope angle of about 1V:3H. Available geological information indicates that the cutback will encounter weathered andesite in the floor and lower part of the cuts, overlain by ignimbrite in the upper part of the cuts. The tunnel portal at the base of the cut slope is expected to be cut in weak to moderately strong andesite rock. Figure 17: Proposed cutback and Waihi plant site to Willows Access Tunnel location (OGNZL). 'WKP portal' shows the proposed portal location.
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