June 2022 G-14642.71-006-R-Rev0_FINAL 12 6.0 WILLOWS ROAD ACCESS TUNNEL AND VENT SHAFT 1 6.1 Geotechnical Investigations 6.1.1 Field mapping Key geomorphological features of Willows Road Farm were identified by WSP using analysis of available aerial imagery and topographic information. This assessment utilised high-quality LiDAR survey data and aerial imagery supplied by OGNZL, and Google Earth satellite imagery. The identified geomorphological features of the Willows Road Farm site are summarised in Figure 3. 6.1.2 Boreholes Fully cored boreholes were completed at various locations to investigate key elements of the tunnel and surface infrastructure. The borehole details are presented in Table 2 and locations of all site investigations are presented in Figure 8. Table 2: Summary of boreholes completed for Willows Road access tunnel. Name Depth (m) Direction Easting Northing Collar RL Purpose WFBH010 7.40 Vertical 2763258.00 6423876.49 220.25 Tunnel alignment between portal and Ventilation Shaft 1 WFBH011 15.08 Vertical 2762897.70 6423934.45 233.18 Tunnel alignment between portal and Ventilation Shaft 1 WFBH012 18.3 Vertical 2762718.66 6424155.79 246.49 Tunnel alignment between portal and Ventilation Shaft 1 WFBH013 16.85 Vertical 2762593.67 6424370.63 205.20 Tunnel alignment between portal and Ventilation Shaft 1 WNDD007 231.7 Vertical 2762468.97 6424304.13 237.63 Approximately 50 m from Ventilation Shaft 1 WNDD008 1043.50 20° inclined (trend ~300°) 2763401.77 6423550.34 235.57 Approximately parallel to access tunnel Geotechnical logs prepared by GHD are reproduced in Appendix C. Additional boreholes and test pits were undertaken at Willows Road farm to evaluate geotechnical issues affecting proposed surface mine infrastructure including a rock stack for temporary tunnel spoil storage (see WSP 2022). These additional investigations are not repeated in this report.
RkJQdWJsaXNoZXIy MjE2NDg3