Reduction of nitrous gases from blast fumes in underground mines using water based absorbency solutions

State of the art in dealing with blast fumes in underground mining operations is ventilation, following the slogan: dilution is the solution to pollution. Today, blasting is one of the key procedures in modern underground mines; it is used for drift development as well as for extraction of raw materials. The resulting blast fumes are one of the major sources for nitrous gases (NO and NO₂) in the mines. The reduction of Occupational Expose Limits (OEL) for these gases in Germany by about 90% in 2016, with a transition period until 2021 for the mining sector and 2023 for the rest of Europe, leads to a big challenge for the mining industry. To keep re-entry times after blasting at least at the present level and thereby ensure an economic operation of the mine, using ventilation solely is not sufficient. For this reason, a new approach to reduce nitrous gases from blast fumes in underground mining operations using spraying systems with aqueous absorbency solutions is described. Laboratory experiments using water, sodium hydroxide (NaOH) and sodium sulfite (Na₂SO₃) were performed. A reduction of NO and NO₂ was observed.