The Research And Application On Spontaneous Potential Methods In Interlayered Oxidation Zone Sandstone-type Uranium Deposits

Sandstone-type uranium deposit in interlayer oxidation zone has little differences with surrounding rock in electrical conductivity, gravity, magnetic and elasticity, and the radioactive rays is hard to penetrate the overlying strata. To some degree, it shows that traditional geophysical methods for sandstone-type uranium deposit in interlayer oxidation zone are insufficient. Both theory and practice show that the SP anomaly can be observed on sandstone-type uranium deposit in interlayer oxidation zone. The SP can be used to explore and determine the front line of interlayer oxidation zone and distinguish uranium mineralization development direction.Based on National Natural Science Foundation of China “Study on Spontaneous Potential Formation Mechanism and Field of ISL-amenable sandstone-type Uranium Deposits in interlayer oxidation zone”, this paper does detailed research with the measured data of the SP in sandstone-type Uranium Deposits in Hong Haigou and Zajistan. The characteristics of groundwater hydrochemistry and hydrogeochemistry in the studied area are analyzed in the beginning of this paper. It shows that the difference of pH-Eh value of in underground water determines the existence and migration of Uranium. The changes in pH-Eh value will cause a series of physical and chemical changes. The research show that the SP anomaly on sandstone-type uranium deposit in interlayer oxidation zone is caused by oxidation-reduction and filtrating electric field. Based on the theory of oxidation-reduction electric field, this paper discusses the character of SP field and establishes mathematical physics model to simulate common actual ore body. Through the theoretic calculation, the paper analyzes the relationship between the SP anomaly and ore body. The improved probability tomography method is introduced in inversion research. The theoretic inversion calculation to ideal model proves that this method is effective.In the end of this paper, a field trial is completed in Hong Haigou and Zajistan. The results are well to determine the front line of interlayer oxidation zone and distinguish uranium mineralization position and outline. The position of uranium ore body is inferred by SP method in the area without drilling. This conclusion will provide accurate and high value of information to further detailed prospecting work.