Fugitive dust dispersion modeling in Mae Moh Open Pit Coal Mine, Lampang Province

Abstract

According to the development of mathematical model by adopting CALPUFF software for simulation of climate and TSP and PM10 dust dispersion in mining and waste dump areas at Mae Moh mine, this study comprises of four main sections: (1) simulation of the climate model, (2) evaluation of the emission sources from the mining activities by using US.EPA AP-42 formulas, (3) investigation of the dispersion in 2016, and (4) comparison between the model data and air quality measured at the monitoring stations within the pit in each season by adopting a statistical technique to conduct a reliability test before using the model in 2022 and 2029. In comparison to the data observed from the meteorological stations, the results from the model reveal that the correlation coefficients of three seasons are 90 % indicating that the climate model is reliable. To evaluate the sources of TSP and PM10, the mining activities are used to calculate the emission factors in 2016 and the results indicate that excavation and haulage are the most dust-releasing activities. By comparison with the dust measured in the areas, the correlation coefficients (R2) of all seasons fluctuate between 0.140 – 0.870 indicating that the dispersion simulation is at moderate. Based on the model developed for the year 2016, it can be applied to predict the dust dispersion in 2022 and 2029. The input data consist of production plans, climate changes in accordance with depth of the mining pit, and emission rates from the main dust-releasing activities. It is found that the dust disperses along the local wind. Moreover, the dust concentration at night is higher than the daytime due to the decrease of the mixing height level, affecting the night shift workers than the daytime shift workers. The deepest location of the pit shows the highest dust concentration. Consequently, workers in this area should wear dust protective equipment, or avoid being in this risky area for a long period.