Geochemical properties and its environmental impacts of the Mazino coal deposit, Central Iran

Abstract

Tabas coalfield is one of the most important coalfields in Central Iran. The area is located in the central desert of Iran, very far from any inhabited areas. Mazino is the largest thermal coal deposit in Tabas coalfield. Coal-bearing strata in Tabas coalfield (as well as in Mazino deposit) are within the Middle Jurassic formations. This sedimentation has been developed in alluvial plain and coastal environment in Tabas coalfield. The coal-bearing sediments mainly consist of sandstone, shale, siltstone, and carbonatic rocks. Several coal seams with different thickness are interbedded with these sediments. Petrographic observations have shown that coals of the Mazino deposit are mainly anthracite to semi-anthracite and dominated by macerals of the vitrinite group; amounts of inertinite macerals are relatively very low. The dominant mineral phases of these coals are pyrite, siderite, calcite, gypsum, illite, and clays. The Mazino coals have high ash (average of 27.78%), low volatile matter (average of 5.2%), and high sulphur (average of 2.62%) content, and high calorific value with average of 22.94 MJ/Kg. The chemical composition shows that the Mazino coals range from semi-anthracite to anthracite (thermal coal), which are suitable as power-plant fuels with low chemical hazards to environment in the area.