| Discharges to Air and Associated Mitigation Methods | Waihi North Project Air Discharge Assessment - Waihi Surface Facilities | 4396626-1331619777-99 | 16/06/2022 | 23 3.3 Products of Combustion The operation of the vehicles used on site will generate the products of combustion, which include PM10, PM2.5, nitrogen oxides (NOx) and carbon monoxide (CO). The results of monitoring of ambient concentrations of air pollutants at the Martha Mine, including those associated with motor vehicles were discussed in the report prepared for the Golden Link Project Area consent applications entitled “Air Quality Implications of Underground Mining in the Golden Link Project Area”.19 The conclusions from that report were: ● The results of ambient monitoring of air quality showed only minimal effects from vehicles associated with mine operations with most measurements well below the Ambient Air Quality Guidelines and the National Environmental Standards for Air Quality ● The only elevated results were recorded when a stockpile was being worked in 1993 within 10m of the monitoring site. This produced elevated results of NOx and a moderate amount of sulphur dioxide (SO2). Extrapolation of the data indicated that levels of both contaminants would be insignificant within about 50m of the activity ● Since the 1993 measurements were made, the sulphur content of fuel has been decreased by 95%, with a corresponding decrease in SO2 emissions from vehicles. Vehicle emissions per kilometre travelled have also decreased over period in response to improvements in emission control technology. Overall, vehicles movements within the site are expected to be comparable to historical levels over the life of project. During this period, vehicle emissions are expected to be similar to previous levels although the distribution of emissions within the site will be different. Higher vehicle emissions are expected to occur during project years 4 and 5 in response to increased construction activity at site. However, based on the results of the previous ambient air monitoring and the separation distances between site operation and sensitive receptors, emissions from vehicle are expected to have a minimal impact on ambient air quality beyond the boundaries of the site. 3.4 Emissions from Blasting on the Surface 3.4.1 Overview Blasting generates emissions of particulates, CO, NOx and small quantities of SO2. Blasting also produces dust generated from the shattering of rock. In the past, the primary explosive used at the mine was ANFO (ammonium nitrate, fuel oil), which produces substantially higher levels of NOx compared to emulsion explosives, which are now used almost exclusively at the mine. Emulsion explosives are a mix of ammonium nitrate, fuel oil or diesel and emulsifiers. Diesel, which has a very low sulphur content compared to fuel oil and produces less SO2 emissions, is favoured. The volumes of explosives used will vary significantly and generally reflect production rates. Best practices will be followed with respect to controlling potential effects and fly rock, including the preparation of a detailed Vibration Management Plan. 19 Rolfe K “Newmont Waihi Gold: Air Quality Implications of Underground Mining in the Golden Link Project Area” March 2012.
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