This mine near the Mouana Mine is the site of over a dozen precambrian natural nuclear reactors. Secondary enrichment of uranium oxides in cm to meter sized veins moderated by ground water consumed six tons of U235 and elevated temperatures to a few hundred Celsius. Remarkably the non-volatile fission products moved only a few cm in the veins during the last 1.5 billion years!
See also Bangombé, another natural nuclear reactor in the same area.
References:- Econ Geol 84 (1989) 2286-2295
- Radiochimica Acta 66/67 (1994) 455-461.
- Dymkov, Y., Holliger, P., Pagel, M., Gorshkov, A., and Artyukhina, A. (1997): Characterization of a La-Ce-Sr-Ca aluminous hydroxy phosphate in nuclear zone 13 in the Oklo uranium deposit (Gabon). Mineralium Deposita 32, 617-620.
- Hidaka, H. (2007): Geochemical characteristics of an ancient nuclear reactor "Oklo". Journal of Nuclear and Radiochemical Sciences 8, 99-103.
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http://www.curtin.edu.au/curtin/centre/waisrc/OKLO/Where/Where.html 27 entries listed. 25 valid minerals.