SUMMARY
Research on anomalous features
of radioactive gas to detect buried ores in placer zones of coastal areas of
Central Việt Nam
Lê Khánh Phồn, Nguyễn Anh Tuấn, Nguyễn
Văn
Theoretical calculation of the concentration of radon and
thoron on the model of the typical body of coastal placer deposits in Central
Việt Nam have been showing that bedded ore bodies contain horizontal beds
of radioactive substance with the dimensions corresponding to half-space of
infinite radiation giving the basis to apply the method of radioactive gas and
to interpret factual materials. Results of the radioactive survey on five
coastal placer deposits in Central Việt Nam have been proving the ability
of detecting buried ores by characteristics of anomaly of radioactive gas. On the
ore body exposed on the surface, the concentration of anomaly of thoron depends
on ore content, but always larger than 3 to 5 times of anomaly of radon. When
the ores are covered, the concentration of thoron will strongly decrease; when
the thickness of covering soil h >80 cm, the anomaly of thoron concentration
will be smaller than radon one, but when the thickness of covering soil 3 m <h<
10 m, the radon concentration will completety disappear and still remains the
ability of detecting weak radon concentration.
Ngày nhận bài: 6/7/2009
Người biên tập: TS. Nguyễn
Tuấn Phong (Cục Địa chất và Khoáng sản Việt
Nam)