Environmental geochemistry of selected elements in lignite from Barsingsar and Gurha mines of Rajasthan, Western India

The present paper contains the result of investigation carried out on selected trace elements in the less studied lignite deposits of Rajasthan, Western India. The study has been made on two new lignite deposits–Barsingsar and Gurha. The former has elevated ash content (mean 20.8%) than the latter one (mean 5.1%) and both of them have high volatile matter (mean 43.7% and 49.9% respectively). The lignite samples have been studied for selected elements like Fe, Ca, Mg, Mn, K, Na, Cu, Co, Ni, Cr, Zn, Pb, Cd and As. The elements like Cd, Co, Ni, Pb and Cu occur in high concentration when compared to the Clarke values for brown coal. Ca and Mg relate positively with organic matter in Barsingsar lignite indicating their organic source while K, Cu, Co, Pb and Cd indicate their inorganic origin. Ca might have come in contact with the organic matter during humification and would have become a part of humate. The elements like Cu, Co, Ni, Cr, Cd and Pb showing strong affinity with inertinite could have got associated with the mineral matter present in the fusinite and funginite macerals. In Gurha lignites Pb and Co have shown their affinity with inorganic matter which could have been drawn from sulphides and clay minerals.