C-V fractal modeling of the pyrite thermoelectric coefficient and estimation of continuation of ore bodies at depth in the Pujon gold deposit, DPR Korea

This paper describes a method for estimating the continuation of ore bodies at depth based on concentration-volume (C-V) fractal modeling of the pyrite thermoelectric coefficient in the Pujon gold deposit, Democratic People’s Republic of Korea. The method is first established using data in the Kumjomdong area, a well-explored brownfield, and it is then applied to estimate the continuation of ore bodies at depth in the Pyongsandok area, a less-explored greenfield. The methodology consists of four steps: (1) 3D modeling of ore bodies using surface geological mapping, mining tunnels in different levels, and a borehole dataset; (2) 3D modeling of thermoelectricity coefficients from Au-bearing pyrites based on discrete smooth interpolation and C-V fractal techniques; (3) determination of levels used for calculation of the thermoelectric parameter of pyrite by C-V fractal modeling instead of traditional levels; and (4) determination of the thermoelectric parameter vertical gradient of pyrite reflecting the variation characteristics of pyrite thermoelectricity in the Pujon deposit. The results indicate that (1) pyrites in the Pujon deposit are dominantly P-type, and it is not reasonable to use traditional levels to calculate the thermoelectric parameter of pyrite; (2) thresholds determined by C-V fractal modeling can be used as levels to calculate the thermoelectric parameter of pyrite; (3) the thermoelectric parameter vertical gradient of pyrite ranges from 1 to 2 in the Pujon deposit; and (4) ore body Pyongsan No. 9 extends 85 m to 235 m downward from the current borehole location.