June 2022 G-14642.71-006-R-Rev0_FINAL 44 Ground conditions are inferred to be unsuitable for raise bore construction. We interpret that a construction methodology that allows suitable support to be progressively installed during construction, such as an Alimak raise, will be required. Main Access Tunnel There is currently no subsurface information available for the main access tunnel alignment between Willows Road Farm and the WUG ore body. The distribution of geological units has been inferred based on surface geological mapping. Tunnelling conditions can be reasonably inferred from geotechnical investigations at Willows Road Farm and WUG, recognising that this information does not provide a complete assessment for tunnel design. Tunnelling will rely on support design and groundwater management based on drill ahead investigations during tunnelling, a method that is commonly used in tunnelling. Wharekirauponga Underground Mine The proposed mine design and mining methodology is believed appropriate for the Wharekirauponga deposit given the current design stage. Geotechnical investigations have been limited to date given the difficult site access for drilling. Efforts to date have largely focussed on exploring the deposit and evaluating the grade. The geotechnical assessment for the mine follows industry practice for the current project stage. Recommendations for areas of future investigation and assessment effort include better characterisation of the geomechanical properties and distribution of the various rock units. This will allow more reliable analysis of the behaviour of the rock mass during mining on which to base the mine design. Feasible options for decommissioning the ventilation shafts are available.
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