Investigation of acidic water generated coal washing plant tailing in central Alborz- Zirab in order to decrease its environmental effects

Residues of mining and coal processing are among the most important resources of acidic drainage production in most parts of the world. So, most of the activities for determining the acidic drainage production resources and also the controlling and neutralizing methods of these drainages are carried out about coal. Central Alborz coal region produces a large amount of residues, which can produce acidic waste waters. Therefore, the said studies were carried out to investigate the capability of acidic wastewater production from these residues and their effect on surface waters of the region. In primary laboratory studies carried out on residues using modified ABA static test determined that residues of floatation and jig are in uncertain limits. So, dynamic test method on water samples wasused to investigate the probable production of acidic wastewater generated by residues of AnjirTangeh coal washing plant. In this method, the quality of water was analyzed and investigates under two climatologic conditions. Samples of flowing waters around the plant were taken using the standard sampling method No. 2347 of Iran. The results show that there were no significant statistical difference between the amounts of these parameters and national standard amounts. The factors like high hardness of water in the region because of limy layers, low underground waters level, clay minerals forming coal ash like montmorillonite that prevents penetration of waters resulting from precipitations into the residues and low percentage of pyrite, as the origin of acidic wastewater production, caused the acidic pollution of central Alborz coal washing plant not to be a threat for environment of this region.