Water vapor and nano-sized coal dust interactions: Experimental insights and numerical modeling

Research over the past decade has significantly enhanced understanding of dust particles and environmental moisture interactions in open settings. However, the impacts of dust and moisture interaction in confined occupational environments remain understudied. This gap is critical for miner health and safety, as exposure to mineral dust in underground mining environments is a recognized problem. Factors such as depth of mining, ventilation, climate, equipment heat, and dust control technologies influence relative humidity (RH) in these spaces. Our study focuses on nano-sized coal dust particles (NSCDs) and their interaction with environmental moisture. We demonstrate that increasing RH directly affects the particle size and mean bulk density of NSCDs. Numerical models accurately predict moisture transport and adsorption on these particles. Key findings show that lignite coal dust, with higher water uptake, exhibits a more significant increase in particle size and bulk density compared to bituminous coal dust. This study underscores the necessity of accounting for these alterations in NSCD characteristics when modeling dust transport and deposition in mines, suggesting that current dust control measures and exposure assessments may overlook the dynamic nature of particle-moisture interactions.