June 2022 G-01483.84-017-R-Rev0 Because the 3 1.2 Previous Work WSP-Golder previously provided a summary report (Golder 2021) of findings for a preliminary geotechnical assessment of various elements described in previous project descriptions based on the available geotechnical information as at 30 May 2021. Since that time the original proposal was reworked into the Waihi North Project connecting the Wharekirauponga access tunnel through to Waihi and additional information made available from ongoing field investigations and studies. 1.3 Scope of Work WSP-Golder’s scope of work included the following assessments: ▪ Geotechnical assessment of tunnel rock storage at the Willows Rock Stack (WRS) and founding conditions for site Surface Facilities Area (SFA) ▪ Geohazard review of the proposed Services Trench ▪ Rock stack construction Prefeasibility Options Assessment ▪ Develop geometric WRS design including: ▪ Staged WRS construction to meet the tunnel excavation material movement schedule ▪ Haul roads and access from the tunnel portal to the WRS and SFA ▪ Concept water management for the WRS, haul road and access road ▪ Collection pond for mine affected water 1.4 Site Visits A site visit was completed by Tim McMorran (WSP-Golder Principal Engineering Geologist) on 20 July 2020. Tim accompanied Dan Calderwood (OGNZL), Fergus Mcarthur (OGNZL) and Holly Janssen (GHD) on a visit to the Willows Road farm site and observed rock and soil outcrops and geomorphology visible from farm tracks around the proposed portal site, waste rock site, silt dam and other infrastructure. Tim visited the site a second time on 22 September 2020 accompanied by Sue Bonham-Carter (WSP-Golder Principal Mining Engineer) and Holly Janssen. An additional site visit was made by Tim McMorran on 20 September 2021 to review the geotechnical issues affecting the two possible WRS locations and associated infrastructure. 1.5 Units of Measure All measurements are metric. 1.6 Co-ordinate System The coordinate system used for the Willows Road element designs is in a modified projection of New Zealand Map Grid (NZMG).
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