A Radon Emanometry Case Study of the Rössing South Deposit, Namibia

The RadonXTM technique uses the principle of adsorption of radon, emanating from buried uranium mineralization, onto activated charcoal. The charcoal is contained within a cartridge which is fitted into the base of an inverted cup, and is buried in the ground for a period of approximately 10 days. The technique differs from alpha-sensitive radon detection systems in that it measures the gamma radiation arising from the daughter products of the adsorbed radon, namely 214Bi and 214Pb. The present case study shows that RadonXTM has an improved sensitivity compared to an alpha detection system, in which cups are buried for a period of 30 days. A case study is presented, in which the RadonXTM radon emanometry technique is sited over the Rössing South uranium deposit. The mineralization occurs under a cover varying between 20 and 80 m, within rocks of the Damara Supergroup and associated leucogranites, in the Central Zone of Namibia. The results show that the deposit, blind in terms of a radiometric signature, has a clear RadonXTM target anomaly signature, making the technique an effective and essential exploration tool in areas of deep cover. An excellent depth of penetration, of 100m or more has been quantified elsewhere in the Central Zone, under favourable permeability conditions.