Typomorphic characteristics of pyrite: Criteria for 3D exploration targeting in the xishan gold deposit, China

Abstract

This paper describes 3D modeling of exploration criteria derived from typomorphic characteristics of pyrite in the Xishan quartz vein-type gold deposit (China). The methodology consists of five steps: (1) modeling of orebody thickness and grade using ordinary kriging in longitudinal section; (2) analysis of major/trace element content of Au-bearing pyrite from each ore paragenetic stage; (3) analysis of thermoelectric parameters of Au-bearing pyrites and estimation of ore-forming temperatures and comparison with homogenization temperatures from fluid inclusion analysis; (4) 3D modeling of orebodies using surface geological mapping, mining tunnels in different levels, and a borehole dataset; and (5) 3D modeling of thermoelectricity coefficients and estimated temperatures from Au-bearing pyrites for exploration targeting via discrete smooth interpolation and concentration-volume fractal modeling. The results indicate that: (1) Au-bearing pyrites from four ore paragenetic stages record gradually decreasing temperatures from the earliest to the latest stages, and the frequencies of occurrence of pyrite crystal combination forms and element components are closely correlated with P-type values of pyrite; (2) orebodies Nos. 108–1 and 107 are continuous at depth and potential exploration targets of their continuations extend more than 700m downward from their present mining levels; whereas orebodies Nos. 55 and 108–2 discontinue at depth.