Appliances to damp deposits of dust in tunnels and workings before and after shotfiring and loading operations. Water sprays are also used along dusty roadways. Various types of mist projectors and atomizers are used and effect considerable improvement, but the dust trapped consists chiefly of the coarser particles. In many dusty mines, a water pipe system extends throughout the workings and sprays are employed at all loading and other dusty points. Sprays are also used to suppress dust at coal and ore processing plants.