252 particles is indicative of gravitational settling. For most of the flights decreasing profile has been observed from pit bottom to the pit top. However, a sudden spike in PM levels were observed at several depths, where the concentration is predominantly higher than the pit bottom. This can be attributed to the mining operations carried out at those locations which emit significant amount of PM into the mine atmosphere. Figure 6 – Vertical profile of different sized PM concentration measured by the UAV Out of morning, afternoon, and evening sessions, higher PM concentrations were recorded during the evening session and lower during the afternoon session. Concentrations recorded during the morning session were significantly higher than the afternoon session but
RkJQdWJsaXNoZXIy MTM0Mzk2