Mine wastewater chemical composition in Khe Cham coal mine in Vietnam: features and some impacts

Quang Tuan Tran1, Van Lam Nguyen2
1 Ruhr University Bochum, Bochum
2 Hanoi University of Mining and Geology, VietnamVietnam Hanoi University of Mining and Geology, Vietnam Hanoi University of Mining and Geology,

P 10.1 in Wasser und Umwelt in Südostasien

Mine wastewater has been a major concern in mining in recent years. The aim of this research was to study the chemical composition of this mine wastewater and some their impacts on coal mining. These included collecting, observing, sampling, and analyzing water at several sites. Two evaluation methods were used: The chemical composition variation assessment of the mine wastewater in 2 years (2008, 2009): (1) over time (based on the monitoring data for the quarterly indicators); (2) by mining depth (selected the monitoring data at this coal mine wastewater monitoring stations in different depths of the pit). The important components of the mine wastewater were indentified and had some signs of the pollution such as low pH value (2.6 and 3.7 in August 2008, and in June 2009 respectively); some heavy metals as Fe, Mn with high concentrations (the maximum value of Fe, Mn, TSS: 96 mg/l; 5 mg/l; and 932 mg/l in 2008 respectively; the maximum value of Sulphate (SO42-): 1711 mg/l in 2009). The two impacts of the mine wastewater: erosion (determined the corrosive components were due to pH, TSS, SO42-,...) and impacts on the surrounding environment were studied. These results suggest that the concentration of Fe, Mn, SO42-, TSS generally exceeded the Vietnamese Standard (QCVN 24:2009/BTNMT), and corrosived the mine equipment. Until now, the quality of mine wastewater is not effectively improved before it is discharged into surface water sources. It is necessary to thoroughly treat them to minimize their impacts.