Self-similar fractal analysis of gold mineralization of Dayingezhuang disseminated-veinlet deposit in Jiaodong gold province, China

The mineralization degree in drifts in the Dayingezhuang disseminated-veinlet gold deposit in Jiaodong gold Province, China, can be categorized into non-mineralized, weakly mineralized, moderately mineralized and intensely mineralized ranks based on the number of the gold grades greater than cut-off. The grades sampled equidistantly and continuously along different drifts at − 140 m, − 175 m and − 210 m levels of the deposit are systematically calculated via the self-similar fractal model. The grade distributions often show bifractal characteristics, including two or three non-scale ranges. It shows that with the increase of mineralized rank, the fractal dimension of the second non-scale range decreases and the corresponding threshold becomes greater. The dimension decrease comes from the increase of proportion of the wider microfracture in the ore-controlling structure system; and the threshold increase is a result from the magnitude elevation of the microfractures from the extension-shear zone to compression-shear zone. The smaller fractal dimension means the proportion of the higher gold grades increases, suggesting the thickness of the orebody is proportional to its mean gold grade.