| Existing Air Quality Effects | Waihi North Project Air Discharge Assessment - Waihi Surface Facilities | 4396626-1331619777-99 | 16/06/2022 | 49 However, the peak TSP concentrations measured at the Site 6.78 (Slevin St) during the monitoring period have been higher than the peak concentration measured at the 6.65 (Old House). The TSP concentrations at Site 6.78 (Slevin St) are on average higher than those observed at Site 6.66 (College) (p-value of <0.01). The results indicate that Site 6.78 (Slevin St) is likely affected by mining activities, but less so than the other sites. Site 6.63 (Met Station) On average, the highest TSP concentrations were recorded at the Site 6.63 (Met Station). The results are consistent with where the peak dust deposition rates also occur. The higher concentrations can likely be attributed to the site’s proximity to the Martha Pit, and its downwind location in the predominant wind direction. TSP concentrations at the site are on average approximately 3.8 – 4.6 µg/m3 higher than those recorded at the sites that appear to be unaffected by mining activities (i.e. Site 6.65 (Old House) and Site 6.66 (College)). However, TSP levels at Site 6.63 (Met Station) have not exceeded the trigger level of 45 µg/m3 since 2009.. The Martha Eastern Perimeter Road was sealed in 2010 which may have contributed to the lower average TSP concentrations observed at the site since 2009. The close proximity of this road to the monitor (<20m) means coarse road dust is likely to be captured by TSP samplers. Sites 6.78 (Slevin Street), 6.64 (Courthouse) and 6.61 (Grey Street) The distribution of TSP concentrations recorded at the 6.78 (Slevin St), 6.64 (Courthouse) and 6.61 (Grey Street) sites are all statistically similar to each other. On average, the TSP concentrations at the sites are higher than those recorded at the background monitoring stations (Sites 6.65 (Old House) and 6.66 (College)) but lower than those recorded at Site 6.63 (Met Station). The higher average TSP concentrations recorded at Site 6.78 (Slevin St), relative to background levels, may in part be attributed to mining activities due to its proximity to the mine and downwind location in the predominant wind direction. Mining activities may at times also contribute to TSP concentrations at Site 6.61 (Grey Street) since it is also located downwind of the Martha Pit in the prevailing wind direction. However, the site is located further from the mine than Site 6.78 (Slevin St) and the contribution from any mine activities to pollutant levels would generally be expected to be lower. Site 6.64 (Courthouse) is located in the Waihi commercial area approximately 310 m south of Martha Pit. The site is downwind of the pit for less than 5% of the time. Mining activities are therefore not expected to be a significant contributor to the TSP levels at this site. The higher TSP concentrations recorded at the site (compared to sites unaffected by mining) are therefore expected to be associated with other emission sources (e.g. transport and commercial sources, home heating emissions) and can be considered to be representative of background concentrations in Waihi Township. The three exceedances recorded at Site 6.64 (Courthouse) are not expected to be associated with emissions from the mine. Summary Overall, the monitoring results suggest that Martha Pit mining activities may have an impact on TSP concentrations at the sites located close to the pit, however at distances of between 150 m and 250 m the impact of the mine becomes less significant and TSP levels are similar to those recorded in other parts of Waihi that are not impacted by the mine. Table 6-5 summarises the results of the TSP monitoring data analysis.
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