An approach to the mathematical modelling of the uranium series redistribution within ore bodies. [Australia]

Abstract

The distributions of the uranium series isotopes in the Koongarra ore body were predicted by a simple one-dimensional model of isotopic migration parameters. Controlling the predictions were the retardation factors and the groundwater flow rates. The conditions modelled were a groundwater flow rate of 1 meter per year, retardation factors of 1 x 10/sup 4/ for /sup 238/U and of 1.2 x 10/sup 4/ for /sup 234/U, and /sup 230/Th is immobile. For this set of conditions, an exceptionally good agreement was observed between field-measured isotope ratios and ''predicted'' isotope ratios. A multiphase model adequately describes the redistribution of uranium and daughter radionuclides in the weathered zone of the ore bodies. It redistributes U, Th and Ra isotopes among an aqueous phase, an amorphous iron phase, a crystalline phase and a phase of clay and quartz. 28 refs., 26 figs., 8 tabs.