ANALYSIS AND SIMULATION OF REACTIVE TRANSPORT IN MINE SPOIL BY A DUAL POROSITY COLUMN STUDY

A column of 25cm length and 10cm diameter was filled with sandstone having minimum to sub-minimum grain size. The sandstone was sampled from a mining site, where groundwater was supposed to be contaminated by the effluents drained from the spoil. The purpose of this study was the simulation of dissolution and reactive transport in the mine spoil. PHREEQC, an one-dimensional geochemical transport model, is used to simulate convective-diffusive transport of bromide through the column. A very good agreement was achieved for the tracer between the measured and modelled breakthrough curves, which resulted in a dispersivity of 0.0012m and was fund that 32% of water in the column could be considered as immobile. Good results were achieved as well for most of the components: chloride, sulphate, calcium, potassium, magnesium and sodium. The analysis and modelling of the effluents suggested that the infiltration of rainwater through the mine spoil might lead to cation exchange and dissolution of minerals in the spoil.