Abstarct: The Mehmandoost coal washery factory is located about 24 Km northeast of Damghan city. This coal washery of unit has been operating under the supervision of the Eastern Alborz Company since 1353. One of the most important environmental problems of waste dumps and is one of the most important environmental pollutants that is caused by the oxidation of sulfide minerals in coal mine waste. Pyrite and Marcasite minerals are the most important minerals in acid drainage production. In this study, the potential of acid production by these tailings has been studied baxsed on mineralogical studies and static experiments (pH and EC saturation mud, acid production or consumption, acid and basic counting, and determination of pure acid production and consumption). The results of the studies show that the coal bed waste has a moderate enrichment than Cu and Mn without enrichment, with moderate enrichment as compared to Zn and Sb with relatively high enrichment, ratio Cd has a strong enrichment and has infinite enrichment relative to As and Pb. The minerals in the waste products include quartz, muscovite, clinocolor, kaolinite, ilite, montmorillonite and calcite and pyrite. Waste numbers 3 and 7 do not produce acid drainage. Because their pH saturation is more than 4, EC has a saturated saturation of more than 2000. Also, in this waste, NNP> +20, NAPP negative, NPR> 3, AG pH> 4.5 N and ANC / MPA ratio> 1. In waste glands No. 1, 2, 4, 5 and 6, because the pH of the saturated water was less than 3 and the EC had a saturation of more than 2000, NNP> +20, NAPP negative, NPR ratio <1, NAG pH <4.5 and ratio <1 ANC / MPA, the probability of acid drainage is high.