Study of particles from the Kafang copper deposit in Gejiu city, Yunnan

Abstract

Samples were collected from the mining area, limestone area, and prospective area proximal to the Kafang copper deposit. The particles were analysed by the transmission electron microscopy (TEM) and the soil samples in the mining area were analysed by the X-ray diffraction (XRD). In the mining area and prospective area, metallic elements in the particles are Cu, Pb, Zn, As, Hg, and Co. Particles collected in the limestone area contain few metallic elements that exist in the ore minerals. Based on analysis of these particles, the following conclusions are made: (1) sizes of the collected particles are 20 – 300 nm; (2) the composition of the soil samples and the particulate samples are significantly different because particles in the particulate samples reflect an origin from geogas; (3) geogas particles have different elemental contents because of different physicochemical properties of the elements and physicochemical environment that the geogas particles experienced; and (4) the Kafang stratiform copper deposit is a granite-related hydrothermal deposit. Metallic elements in geogas particles occur in the ore minerals and have similar compositions to those of geogas particles in the sampling sites. The geogas particles most likely originate from concealed deposits. Supplementary material: EDS spectra of particles and coordinates of sampling points in the mining area, limestone area, and prospecting area are available at: https://doi.org/10.6084/m9.figshare.c.3820687