Physical, mineralogical and wetting characteristics of dusts from Interior Basin coal mines

Two approaches were used to assess dust wettability rates: 1) fixed-time wettability that attempts to simulate wetting around mining environments, and 2) absolute-time wettability that evaluates intrinsic wettability rates. Fixed-time wettability for coal dusts were in the range 57-99% (% wt.) with majority of mines having values above 90%. The middle portion of the coal seam was found to be least wettable. The contact time between dust particles and water droplets was an important factor for improving wetting of coal dust. An increase in contact time from 10 to 25 s showed 3-27% improvement in fixed time wettability. Absolute-time wettability data showed that coarser particles required more time for complete wetting. The data above is being actively used to design engineering controls for improved dust control in mines.