GHD | Oceana Gold New Zealand Ltd. | 12552081 | Waihi North Project 16 Table 4 Regime D Discharge Water Quality Range of Concentration Consented Water Quality Chemical Parameter Mean Max Normal Compliance Maximum Compliance pH 8.6 8.9 6.5 – 9.5 Cyanide (g/m3) 0.016 0.02 0.11 0.32 Iron (g/m3) 0.039 0.06 0.5 3.1 Manganese (g/m3) 0.014 0.051 0.5 0.6 Copper (g/m3) 0.0013 0.0029 0.0331 (0.112)2 0.061 (0.264)2 Nickel (g/m3) 0.0009 0.0012 0.551 (2.04)2 Zinc (g/m3) 0.0018 0.003 0.361 (1.36)2 Silver (g/m3) 0.00018 0.0003 0.011 (0.080)2 0.0141 (0.203)2 Antimony (g/m3) 0.006 0.013 0.06 0.1 Arsenic (g/m3) 0.0018 0.002 0.66 Selenium (g/m3) 0.0032 0.018 0.07 0.12 Mercury (g/m3) <0.000083 <0.000083 0.0005 Cadmium (g/m3) 0.00009 0.0001 0.0041 (0.013)2 Chromium VI (g/m3) <0.01 <0.01 0.04 Lead (g/m3) 0.00017 0.0002 0.0111 (0.079)2 TSS (g/m3) 3.1 5 8 40 Ammoniacal N (g/m3) 1.13 2.70 1.13 –18.004 4.98 – 209.984 *Trace element concentrations and acid-soluble and based on unfiltered samples 1. Based on a hardness concentration of 315 g/m3 CaCO3. Actual compliance concentrations for these elements vary depending on the recorded hardness in the discharge. 2. Based on the mean and maximum recorded hardness concentrations of 1359 and 1610 g/m3 CaCO3 over the given period. 3. Mercury has a mdl of 0.00008 mg/l therefore the actual mercury concentration is less than given. 4. Dependent on discharge pH and temperature. Consent refers to Total Ammonia.
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