| Existing Air Quality Effects | Waihi North Project Air Discharge Assessment - Waihi Surface Facilities | 4396626-1331619777-99 | 16/06/2022 | 43 Figure 6-2 Box and whisker plot of monthly average deposited dust monitoring data (January 2000 – December 2020) Figure 6-3 show the rate observed between 2000 and 2020. The deposited dust monitoring results show that for the majority of time, deposited dust levels are below the MfE GPG and consent trigger values of 4.0 g/m2/30-days. Deposition rates have exceeded the trigger value on 4 occasions since January 2000 – twice at Site 6.71 (Morrison), and once at both Site 6.63 (Met Station) and Site 6.70 (Smith). No exceedances have been recorded since November 2012. The recorded exceedance of the trigger value recorded in 2000 at Site 6.7 (Smith) of 11.66 g/m2/30-days appears to be an extreme outlier value and likely consequence of an abnormal event. This outlier value was omitted from the data for the statistical analysis. This assumption is supported by the lower deposition rates record at the site during the 20-year monitoring period. The second highest concentration measured at the Site 6.7 over the 20-year monitoring period was 3.01 g/m2/30-days. Only one exceedance of trigger value has been recorded at Site 6.63 (Met Station) since March 2001, which OGNZL has advised was most likely to be due to contamination of the sample with bird droppings, and therefore not directly associated with site activities. The two exceedances at Site 6.71 (Morrison) were recorded March 2000 (5.23 g/m2/30-days) and March 2001 (4.76 g/m2/30-days). Since March 2001, the maximum deposition rate recorded at the site has been 3.24 g/m2/30-days. 6.00 (Bulltow n Rd) 6.59 (Torrens-Alex) 6.60 (Torrens-TE) 6.61 (Leaches) 6.63 (Met Station/Of f ice) 6.66 (College) 6.7 (Smith) 6.71 (Morrison) 6.72 (Baxter Rd) 0 1 2 3 4 5 Monthly Deposition Rate (g/m2/30-days)
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