Speaker
Description
As global uranium demand increases to support clean energy transitions [1], understanding the environmental impacts of exploration activities becomes essential for sustainable resource development. While extensive research exists on operational mining impacts [2], the radiological consequences of preliminary exploration activities particularly test pit excavation and rehabilitation remain poorly characterized, especially in sub-Saharan Africa where uranium exploration is expanding rapidly [3]. This presentation will describe a comprehensive radiometric assessment of uranium exploration test pits in Botswana using a dual-detector validation approach. The study employed complementary detection systems: a Mobile Radiation Detection Unit (MRDU) for broad area surveys and an InSpector 1000 for point measurements. This allowed for characterization of radiation environments across the 144 km² Letlhakane Uranium Project lease area. Results from investigation of four test pits (one open, three rehabilitated) and 52 measurement locations will be presented revealing spatial variability in radiation levels. Significant radiation enhancements were observed with rehabilitated areas averaging 377.8(19) nGy/h (6.4 times global background levels) while the open pit reached 800 nGy/h (13.6× enhancement). Remarkably, undisturbed areas showed moderate elevation (76.2(4) nGy/h).
The presentation will demonstrate how realistic exposure scenarios (20% outdoor occupancy, 2000 h/y occupational exposure) yielded Annual Effective Dose Equivalent calculations of 0.107(5) mSv/y for undisturbed areas and 0.529(26) mSv/y for rehabilitated sites, following UNSCEAR recommendations [4]. Approximately 95% of measurements remained within international safety limits (1 mSv/y) [5], though some localized "hotspots" reached 1.64 mSv/y, warranting further remediation considerations. Cross-validation results between detection systems will be presented, showing excellent agreement in uniform areas (8% difference) but small differences in heterogeneous environments (1.7× factor). The findings demonstrate that exploration activities may create persistent radiation modifications that rehabilitation efforts only partially address. The distribution patterns were characteristic of environmental contamination which suggested incomplete restoration of pre-disturbance conditions. Generally acceptable exposure levels under realistic scenarios indicate that well-managed exploration can proceed safely with appropriate monitoring that is consistent with IAEA guidelines [6]. This study establishes the first quantitative baseline for the uranium exploration site and will present a validated, replicable framework for environmental radiation assessment in uranium-bearing regions worldwide.
1] OECD Nuclear Energy Agency and IAEA (2023). Uranium 2022: Resources, Production and Demand. OECD Publishing, Paris. https://doi.org/10.1787/499d4341-en
[2] United Nations Scientific Committee on the Effects of Atomic Radiation (2008). Sources and Effects of Ionizing Radiation, UNSCEAR 2008 Report to the General Assembly, with Scientific Annexes. United Nations, New York
[3] World Nuclear Association (2023). World Nuclear Association Country Profiles: Africa. Available at: https://world-nuclear.org/information-library/country-profiles/others/africa.aspx
[4] United Nations Scientific Committee on the Effects of Atomic Radiation (2008). Annex B: Exposures of the public and workers from various sources of radiation. In: Sources and Effects of Ionizing Radiation, UNSCEAR 2008 Report, Volume I. United Nations, New York, pp. 233-320
[5] International Commission on Radiological Protection (2007). The 2007 Recommendations of the International Commission on Radiological Protection. ICRP Publication 103. Annals of the ICRP 37(2-4), 1-332
[6] International Atomic Energy Agency (2020). Occupational Radiation Protection in the Uranium Mining and Processing Industry. IAEA Safety Reports Series No. 100. IAEA
