Mineralogy and geochemistry of trace and rare earth elements of the Chah Badam Coal mine, Yazd province

Chah Badam coal mine of Yazd province is a part of central Iran zone. The main outcrop of the mining area is micacious sand shale with coal veins belong to early Jurassic age. According to petrographic studies, vitrinite is the most important maceral in the coals of the study area, and exinite and inertinite macerals are less abundant, thease coals belong to the clarodorite lithotype XRD studies indicate the presence of quartz, illite, dolomite and gypsum minerals in the coals and shaly coal of the study area. In this research, the Pb element was found with concentration coefficient more than 7 (CC>7) compared to the global average of coal. Most of the samples are slightly enriched (CC=2-5)with other rare elements including Bi, Mo, Sc, Zn, W. Elements such as Pb, Mo, Zn, Ag, As, Cu, Mo, Mn, Se, Ti, Zn, Co, B, Ba show a positive correlation with SO3, which indicates the association of these elements with sulfide and sulfate phases. The results of geochemical analysis for all rare earth elements had lower values than the average of bituminous coal in the world, which is affected by the nature of their primary constituent minerals, which entered the coal field in the form of debris under the influence of erosion.The positive correlation between rare earth elements with oxides such as SiO2, Al2O3, K2O and the negative correlation of these elements with SO3 and CaO indicates the detrital origin (presence of clay minerals such as kaolinite and illite) for rare earth elements.