Preliminary studies on deep-penetrating geochemical methods in exploration for concealed volcanic-type uranium deposit

Abstract

Volcanic-type uranium deposit is one of the most important type of uranium resources in China. It has been proved by the scientific deep drilling work accomplished in 2015 that uranium mineralization can be detected at the depth of more than one thousand meters, where there are no significant radiometric or other exploration geochemical anomalies that can be acquired on ground surface. With the progress of exploration for uranium resources in China, deposits which are exposed on surface or shallow-buried are all almost discovered already. It has become a challenging task to explore the deep-buried deposits for uranium geologists. Application experiments are carried out in Xiangshan uranium deposit field using two kinds of deep-penetrating geochemical methods, including the Selective Leaching of Mobile Metals(MOMEO) and Electro-geochemistry techniques(CHIM).The U ore bodies are manifested as a clear CHIM anomaly of U. The adsorbed and exchangeable forms of U obtained with the MOMEO technique is demonstrated as lower single peak anomalies compared with the CHIM technique. The ‘total’ U element content shows no clear anomaly over the uranium mineralization, while there is only a single point high value with an intensity up to 12.5 ppm of U. The polonium-210 shows no significant anomalies over the uranium mineralization.According to the results obtained in this paper, two kinds of deep-penetrating geochemical signatures demonstrate more effective role in detecting the concealed uranium mineralization than traditional methods. The deep-penetrating geochemical methods are bound to play an important role in exploring for deep-buried and concealed uranium deposits in China.