COLUMN LEACHING OF UNRETORTED AND RETORTED OIL SHALES AND CLAYSTONE FROM THE RUNDLE DEPOSIT - WATER LEACHING

The chemical compositions were determined for leachates from both small and large columns containing a number of solid waste components likely to be present in the dumps of a future shale oil industry on the site of the Rundle oil shale deposit. Samples of unretorted and retorted shales and interburden claystone were studied. These materials were leached both individually and in admixture under unsaturated flow conditions with distilled water. Long term trends in leachate composition were obtained by maintaining each of the columns for at least one year. A number of components in the first pore volume of leachate from some of the columns were found to exceed Australian drinking and irrigation water criteria. These were Mn, NO3, Mo. As, Se and B. Thiosulphate was present in high concentrations in the leachate from retorted shale. Almost 50% of the Cu and Ni leached from the Kerosene Ck shale was present in the form of metallo-organic complexes. The composition of leachate in the first pore volume from both the small and large columns was found to be the same, indicating that the results of small scale column tests may provide a good model for the leaching of the actual waste dumps to be constructed at Rundle. © 1990.