Abstarct: Investigating the speciation of potentially toxic elements in waste dump systems provides valuable knowledge about their mobility and pollution risks in mining sites. Sequential extraction analysis is a common experiment which is often used to determine the speciation of potentially toxic elements. However, there would be some drawbacks when this method is used especially in mine waste dumps. These drawbacks include labour-intensive procedure, interferences of fractions, being inadequate for heterogeneous media such as mine waste dumps, re-sorption and re-distribution of elements and inability in exact determining inability in exact determining the mineral phases controlling elements concentration. This study attempts to develop a new method for investigating the speciation of potentially toxic elements in mine waste dumps using the statistical correlation analysis. This method is baxsed on the correlation between toxic element concentrations and the mineralogical data obtained from XRD and ASTM-2492 analyses which determines elements speciation at different paste pH classes. In order to implement the method, 60 samples were collected from the Nos. 19’s and 31’s waste dumps at the Sarcheshmeh porphyry copper mine. The samples were analyzed by ICP, XRD, ASTM-D2492, paste pH, sequential extraction and grain size distribution methods. To delineate different aspects of waste heterogeneity in the study dumps baxsed on the gathered data and field surveys, the wastes were geochemically and physically investigated, to gether with considering the main mechanisms affecting the weathering of waste materials. The results show that, the waste materials are entirely heterogeneous due to the abundance of acid producing and neutralizing minerals contents and also adsorbent minerals of potentially toxic elements. This heterogeneity can also be seen in the grain size distribution, the permeability and the type of waste material manner (Rock like or Soil like). The air convection is the governing mechanism of oxygen supply and pyrite oxidation in the study waste dumps. The heat generated by pyrite oxidation process and also the evaporation of the waste moisture form a warm and humid air circulation system in the waste dump. Considering the inter-granular void space of the wastes, the convection process of the air circulation system results in pyrite oxidation at different rates and increases the heterogeneity of the dump from geochemical and mineralogical point of views. After characterizing the waste heterogeneity, the proposed method was employed for speciation of potentially toxic elements. The results show that, pyrite was the main mineral for liberating As, Cd, Co,