Studying Hygienic Status of Mechanized Long Wall Face from the Perspective of the Existing Dust Containing Silica in Tabas Coal Mine

In order to consider the quantity of the existing negative effect in mechanized longwall mining face in Tabas coal mine, the concentration of the available coal dust and amount of its toxicity in every part of the mining face and tail gate were investigated and compared with the permissible amount. After sampling and preparing dust, its concentration was determined by gravimetric method. Then, using Zetasizer, the particle size distributions were determined and also the available amount of silica in the samples was found using SEM and XRF device. The results of the elemental analysis of dust in the mine showed that the weight percentage of silica in dust was between 27.9 and 26.7 %. The correction of the permissible dust concentration from the perspective of silica was done and the result was reported as 0.36 mg/m³. Computational fluid dynamics can be used to determine dust accumulation zones and the zones with high dust concentration. Finally, D₅₀ of the samples showed that the existing toxicity in dust can be transferred to dozens of meters far from the source (shearer).