Dust Control Handbook for Industrial Minerals Mining and Processing

Figure 3.21. A fogger spray used to create a mist for dustsuppression in the heading where blasting will occur.Air Filtration SystemsAnother dust control method that has been used in underground mining operations in the past isto filter the return air of the ventilating air in the blasting area as seen in Figure 3.22. One suchfiltration unit, used in South Africa, consists of a filter and a bed of vermiculite treated withsodium carbonate and potassium permanganate which removes the dust and nitrous fumes fromblasting [Cummins and Given 1973]. Figure 3.23 shows another method, which is to placefilters inside the exhausting ventilation duct with water sprays, which spray on the filters and areoriented in the same direction as the airflow. The filters are only used during blasting, and theduct containing the filters is approximately twice the diameter of the ventilation tubing[ILO 1965]. Also, dry filters have been used successfully in the past for the same purpose.Drilling and Blasting 103