Application of coalfield logging data in prospecting target area of uranium deposit in coal measures in northern Guizhou

The Late Permian of northern Guizhou is composed of two and a half paralic sedimentary cycles. It is a favorable area for the formation of coal and uranium deposits. Through comprehensive analysis of logging data of Upper Triassic Permian coalfield in northem Guizhou Province, the natural gamma anomaly of pyrite and clay rock in bottom of coal measures was found. Test and analysis of the data through related rock samples, show that the natural gamma anomaly was mainly caused by radioactive element uranium. using correlation between natural gamma field and uranium content, it is indicated that the natural gamma range less than 3.79 PA·kg^-1 (the mass fraction of uranium is less than 0.010 111%) was classified as normal values, the natural gamma race greater than or equal to 3.79 PA·kg^-1 and less than 10.29 PA·kg^-1(the uranium mass fraction in 0.010 111%~0.030 027%) as coal uranium mineralization anomalies(potential)value. The natural gamma race greater than or equal to 10.29 PA·kg^-1 (uranium mass fraction is higher than 0.030 027%) is classified as coal uranium (potential)abnormal value.The anomaly of natural gamma in the field of coal logging was explained, the areas of the Late Permian coal and uranium mineralization anomalies (potential) and prospecting target area in (potential) anomaly areas were delineated. The target area distributed around Guandian syncline, Songkan syncline and grave dam syncline, Metallogenic belt is located in pyrite clay of the bottom of coal stratum in the Longtan Formation of Late Permian, controlled by Longtan Formation and Maokou Formation. Comprehensive evaluation showed that the abnormal continuity of prospecting target area is better. According to the correlation related calculation, the average uranium content was 0.018 558%, surpassed the boundary grade, has a better potential for prospecting uranium deposits in coal measures.