Supporting Technical Assessments

www.valenza-engineering.com 381_R_04_Rev 0 OGNZL_WUG_Phase1_Conceptual_Mitigation LIST OF FIGURES Figure 2-1:WUG Vein System..................................................................................................3 Figure 3-1:WUG Proposed Tunnel Alignment ..........................................................................7 Figure 3-2:Tunnel Alignment Showing Hydrogeological Significant Features (Golder, 2021) ...8 Figure 4-1:Otahu Catchment (after GWS) ..............................................................................13 Figure 4-2: Spring Discharges and Radon Concentrations Indicative Groundwater Flow (after GWS) 14 Figure 4-3:Spring Locations, Groundwater Contours and T-Stream and EGV Veins (after GWS) .....................................................................................................................................15 Figure 5-1: Access Tunnel CHM for Waihou Groundwater Catchment (after CWS) ...............16 Figure 5-2: Access Tunnel CHM for Otahu Groundwater Catchment (after GWS) .................17 Figure 5-3: Schematic cross section of WKP-102 and WKP-04D (left) and WKP-101 and WKP-103 (right) (after FloSolutions) ......................................................................................22 Figure 5-4: Schematic cross section of WKP-104 (left) and WKP-03D (right) (after FloSolutions) ..........................................................................................................................23 Figure 5-5: Illustrated Tunnel Probing and Grouting Zones ....................................................26 Figure 5-6: Details of Tunnel Probing and Grouting Zones.....................................................26 Figure 5-7: Illustrated Grouting Zone from Surface Positions within the Mine Area ................27 Figure 5-8: Illustrated Grouting Zone from Underground Grouting Chambers ........................27 Figure 6-1: Groundwater modelling process (modified after Barnett et al. 2012) ....................31 Figure 6-2: Example of zones where operational (secondary and tertiary treatment) might be required..................................................................................................................................33 Figure 6-3: Combined Instrumentation and response grouting in a stopping configuration (adapted from MMG Dugald River trial stoping - Underground Design Methods 2015 – ACG) ..............................................................................................................................................34 Figure 6-4: Typical grouting pattern for tunnel sections (after Grouting Specialists) ...............35 Figure 6-5: Grouting and Instrumentation completed from Underground Chambers developed in conjunction with the Declines and Drives ...........................................................................35 Figure 6-6: Dewatering and Instrumentation completed from Underground Chambers developed in conjunction with the Declines and Drives (deep dewatering wells are shown in blue dotted lines)....................................................................................................................37 Figure 6-7: Example of active pore pressure monitoring within a UG block. ...........................39 Figure 6-8: Example of active temperature monitoring within a hot UG mine. ........................39 Figure 8-1: Proposed piezometer locations ............................................................................44

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