Probabilistic prediction of pyrite oxidation process within Anjir Tangeh coal wastes pile

More than 21 Mt of coal wastes is being produced by Anjir Tangeh coal washing plant during 22 years. Wastes have been deposited in the area without considering of environmental regulations in such an unspoiled area. Moreover, the pervious researches revealed that the pile has a potential of acid mine drainage generation. Therefore, it is essential to present a model for investigating risk of acid mine drainage generation in this pile. This paper presents a probabilistic method to prediction of acid mine drainage is being generated within Anjir Tangeh coal wastes pile. After building a database, pyrite remaining fraction and pH were considered as output data while depth of the wastes, bicarbonate concentration and oxygen fraction were input parameters. Then, the best probability distribution functions were presented on each of input parameters applying Monte Carlo simulation. Also, the best linear statistical relationships between input data and output data were presented. Afterward, the best probability distribution functions of input parameters were inserted to the relationships to find the probability distribution functions of output data. Eventually, the results revealed that the remaining pyrite fraction and pH values were lower than 0.894 and 4.6 at a 5% probability level, respectively.