Abstract Helium, a nonradioactive and chemically inert gaseous element, is generated from radioactive decay of U238, U235 and Th232 series. Its stability and high permeability enable it to migrate farther away than Rn222 and form helium halos above and near the sources. Fracture zones and faults, which provide favourable conditions for helium migration, are positions where anomalous helium content is expected to be recorded. Helium survey, therefore, can be used both for geological mapping and for uranium exploration.Since 1970s, the research work on helium method in China has gained rapid advances. Amobile helium mass-spectrometer (Model HE-602)with helium sensitivity higher than10 ppb and measuring precision ±2-3% was developed by Beijing Uranium Geology Research Institute (BUGRI) in1978. All sampling techniques applied are now available, and all samples (soil gas, water and soil) collected in such a way have proed to be of good representativeness.The data acquired in the past few years at 17 uranium deposits and their neighbouring areas demonstrate the existence of helium anomalies over both uranium orebodies and tectonic faults controlling uranium mineralization. Some promising areas defined by helium anomalies have turned out to be really enriched in uranium. Furthermore, helium survey can also find application in earthquake prediction and geothermal prospecting.
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