Wastewater and stormwater minimisation in a coal mine

This paper presents a case study on the application of cleaner production principles in the mining industry. The water balance prepared for the case study showed that less than 20% of the wastewater generated by the colliery is discharged off-site. The remaining 80% of the wastewater is recycled back into the colliery. Modeling of the stormwater system showed that 75% of the clean runoff becomes contaminated through poor management practices. It was also found that the present system of stormwater management causes the process wastewater management system to fail in wet weather. Improved process and stormwater management systems are proposed. Relatively simple alterations to the operation of the coal wash filtration dams are expected to reduce the periods of inefficient operation of these dams by 95% and the pumping cost by 30%. The use of stormwater diversion channels and retention basins reduces the overflow volumes of the process wastewater treatment dams in 5 year average recurrence interval (ARI) storms by 100%. The paper also includes several recommendations for reducing the production of process wastewater at source and off-site disposal of wastewater.