Measurement and analysis of airborne dust generation and dispersion from low-profile dump truck haulage in underground metalliferous mines

Abstract

Exposure to harmful dust increases the risk of respiratory diseases among miners. This study employed high-resolution aerosol spectrometers to investigate the generation and dispersion of airborne dust resulting from operating low-profile dump trucks (LPDT) in a fully mechanised underground metalliferous mine (FMUMM). The aim is to measure and analyse the generation-transport-exposure dynamics of airborne dust from five different real-life scenarios due to the movement of loaded and empty LPDT in decline. The dust generation and dispersion profiles of various particle sizes, viz. ≤1 μm (PM1), ≤2.5 μm (PM2.5), ≤5 μm, ≤10 μm (PM10), and ≤20 μm, and occupational dust types which are vital for dust suppression and occupational health hazards were analysed. The study revealed that the proportions of ≤1 μm, ≤2.5 μm, ≤5 μm and ≤10 μm dusts were in the range of 0.4–3.2 %, 0.9–6.1 %, 3.7–16.9 % and 15.1–38.8 %, respectively. Loaded LPDT generated 77 % and 213 % greater TAD than the empty LPDT in homotropal and antitropal ventilation scenarios, respectively. The morphological analysis revealed that the dust particles are angular and irregular in shape. The mine dust exhibited hydrophilic nature. The wetting of the decline floor reduced the aerosolisation of 0.23–5.0, 5–10, 10–15, 15–20, and >20 μm size dusts in the decline by 57 %, 62 %, 62 %, 67 %, and 72 %, respectively. The regular wet suppression application efficacy increases with particle size in the decline. The study utilised Ventsim software to create and simulate 3D decline model, providing insights into the transport and distribution of airborne particles of different sizes. The field measurement and simulation result imply that respirable particles (≤10 μm) settle slowly in the decline, indicating that dilution is an effective strategy for controlling dust exposure in FMUMMs.