Controlled air recirculation consideration for Canadian hard rock mining

Recirculation of air is a widely used technique in general ventilation and air conditioning practise.Interest in the application of controlled recirculation of ventilation air in mines has grown considerably in the last decade. This is evident by the number of controlled recirculation schemes which have been implemented or are being considered or planned in several countries and in different types of mines.A detailed description is given of the operating and proposed schemes in South African gold and U.K. coal mines. This includes safety, dust filtration and blast contaminant removal systems.The monitoring and feasibility methodology required to evaluate controlled recirculation for heat reclamation, and thus cost saving, in Canadian hard rock mines, is then examined.Experimental work pertaining to air quality study, carried out at three mines, is described in detail, and backed up by extensive appendices.The observed deposition of dust and reduction in gaseous pollutants concentration in exhaust shafts are analyzed and depicted in several figures and tables.Simplified theoretical aspects of dust deposition, and statistical analysis of the obtained results, are outlined