Application of power-spectrum-volume fractal method for detecting hypogene, supergene enrichment, leached and barren zones in Kahang Cu porphyry deposit, Central Iran

The aim of this study was to identify various mineralization zones especially supergene enrichment and hypogene zones in Kahang Cu porphyry deposit by higher than 60 million tonnes of sulfide ore with an average grade of 0.6% Cu and 70 ppm Mo, which is situated in central Iran, based on analyzing the subsurface data using a proposed power spectrum-volume (P-V) fractal method. P-V method is used in frequency domain provided by application of Fourier series transformation on assay data. Straight lines fitted through log-log plots, showing P-V relations for Cu, were employed to separate supergene enrichment and hypogene zones from leached zone and barren host rock in the deposit. In the proposed P-V fractal method, the identification of mineralization zones is based on power-law relationship within power spectrum field (S) and the rock volume hosting Cu mineralization at different grades by applying a V(>= S) proportional to S-2/beta multifractal model. The subsurface data from deposit was analyzed by P-V fractal method and the results have been compared with geological models which included alteration and mineralogical models. The comparison shows that the interpreted zones based on the P-V fractal method have noticeable consistency to the geological models. The proposed P-V method is its either new approach to define zones in a mineral deposit and there was no professional software available to perform the relevant calculations; therefore, Fractal Power Spectrum-Volume (FPSV) software was programmed by the authors to achieve this goal. (C) 2011 Elsevier B.V. All rights reserved.