GHD | Oceana Gold (New Zealand) Ltd | 12552081 | Waihi North 142 Table 6.4 Mataura Stream water quality (values in mg/L) Parameter Existing water quality* (median values) Predicted water quality after WRS seepage mixing Receiving water quality criteria Median Maximum Al 0.04 0.04 0.04 As 0.001 0.001 0.001 0.19 Ca 2.4 2.4 6.5 Cd 0.00005 0.00005 0.00006 0.0003 Co 0.0002 0.0002 0.001 Cu 0.0005 0.0005 0.0005 0.003 Fe 0.04 0.04 0.2 1.0 Hg 0.00008 0.00008 0.00008 0.000012 K 1.2 1.2 1.3 Mg 1.4 1.4 3.3 Mn 0.003 0.0035 0.4 2.0 Na 7.0 7.0 7.9 NH3-N No data No result (increase of 0.00008) No result (increase of 0.02) 0.19 Ni 0.0005 0.0005 0.003 0.04 Pb 0.0001 0.0001 0.0001 0.0004 Se No data No result (increase of 0.000001) No result (increase of 0.00005) 0.02 Sb 0.0002 0.0002 0.0002 0.03 SO4 9.0 9.1 27 Zn 0.002 0.002 0.003 0.027 Notes: Receiving water quality criteria values for hardness 20 g/m3 CaCO3 Values in bold indicate an exceedance of the receiving water quality criteria * Median from sampling results at sites Mataura 1 and 2 (Section 6.2.2) ** The mercury (Hg) criterion is lower than available laboratory detection limits Denotes a predicted increase from existing surface water quality (note: not all increases are expected to be measurable) Table 6.5 Predicted mass flux (kg/d) to the Mataura Stream Parameter WRS (maximum height) Al 0.003 As 0.00002 Ca 4.2 Cd 0.000008 Co 0.001 Cu 0.00002 Fe 0.14 Hg 0.000004 K 0.1
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