Computer simulation of radon contamination levels around controlled district recirculation circuits

Abstract

Research work carried out during the 1960s and 1970s indicated that significant concentrations of radon daughters could be encountered in underground coal, tin, haematite and fluorspar mines as well as in uranium mines. This study indicates that radon-related radiation could occur and constitute a health hazard in non-uranium mines. As a result, research initially concerned with the radon-related contamination in uranium mines was extended to consider the radiation hazard encountered in non-uranium mines, including coal mining. The recent introduction of controlled district recirculation circuits within a number of South African gold mines and a UK coal mine has promoted new interest in assessing the effects that controlled recirculation may have on the levels of radon-related contamination. This paper describes a computer program which was developed in order to predict the possible effect that the introduction of controlled recirculation may have on the residence time and hence radon daughter levels. The results of a series of simulation exercises performed on representative mine ventilation networks are described. These results are compared with available published underground data and general conclusions are presented.