GHD | Oceana Gold NZ Ltd | 12552081 | Geochemical Assessment Wharekirauponga Underground Mine (WAI985-000-REP-LC-0013) 21 Figure 14 Box plot showing the acid neutralising capacity in spoil material Figure 13 shows that data associated with the WUG Mine has a significantly lower mean sulphur concentration of 0.91 % when compared to the Willows Access Tunnel dataset (mean concentration of 3.57 %). Moreover, sulphur concentrations for Willows Access Tunnel are comparable to the current Waihi dataset (AECOM, 2018; AECOM, 2022) which ranges from 0.1 % to 3.0 %. It should be noted that the geochemical abundance index for WUG Mine still has a value of four which is on par with the lower limits of the existing Waihi dataset (Table 1 and Table 2). Similar to the trace and major elements, the distribution of sulphur in Figure 15 shows a pattern of increasing concentrations for sulphur with depth or within the rhyolitic material closest to the orebodies. Figure 15 Cross-sectional View displaying Sulphur Concentrations for the EG-Vein (right) and T-Stream (left) Orebodies ANC values derived from core representative of the Willows Access Tunnel are comparable to the Waihi dataset. AECOM (2022) noted that historic overburden concentrations for the Waihi Martha material had a mean ANC value of approximately 6.0 % CaCO3 equiv. ANC values derived from core representative of the WUG Mine are depressed when compared to the Willows Access Tunnel (mean values of 0.73 % CaCO3 equiv. and 6.09 % CaCO3 equiv. respectively). AECOM (2022) noted that historic overburden concentrations for the Waihi Martha material had a mean ANC value of approximately 6.0 % CaCO3 equiv. which is comparable to ANC values observed within the Willows Access Tunnel.
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