Vol.:(0123456789) 1 3 Environmental Earth Sciences (2018) 77:698 https://doi.org/10.1007/s12665-018-7885-5 ORIGINAL ARTICLE Geochemical implications of minerals and environmentally sensitive elements of Giral lignite, Barmer Basin, Rajasthan (India) Pramod K. Rajak 1  · Vijay K. Singh 1  · Prakash K. Singh 1  · Asha Lata Singh 2  · Narendra Kumar 3  · Om Prakash Kumar 1  · Vishvajeet Singh 1  · Aniruddha Kumar 2 Received: 18 January 2018 / Accepted: 27 September 2018 © Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract The Barmer Basin of Rajasthan is signifcant for its Paleogene lignite sequences. The lignite seam occurs in Akli Formation of Barmer Basin at the depth of 06–241 m. A total of 57 lignite samples were collected from the working faces of lignite mine and were subjected to proximate analysis (moisture, ash yield, volatile matter, and fxed carbon), ultimate analysis (carbon, hydrogen, nitrogen, oxygen and sulfur), elemental analysis (Fe, Ca, Mg, Cd, Mn, K, Na, Cu, Co, Ni, Cr, Zn, and Pb) and rock-eval pyrolysis for mineral carbon (MINC). Some elements like Cu, Cd, Co, Ni, Zn, Pb, Na, and K occur in high concentration, while Mg and Ca have their concentrations lower than World Clarke average. In addition, various minerals and functional groups present in the lignite samples were analyzed through X-ray difraction and Fourier transform infrared (FTIR) spectroscopy. The mineral (weight and atomic) percentage has also been analyzed through scanning electron micros- copy–energy dispersive spectroscopy (SEM–EDS). Keywords Giral lignite · Barmer Basin · Rajasthan · Geochemistry Introduction Coal is an organo-clastic sedimentary rock comprising of macerals and varied proportions of mineral matter. All the inorganic non-coal material associated with coal as mineral phase is generally refected as Mineral Matter (Gluskoter 1975). More impetus is now being given on the study of mineral matter due to their detrimental efect on environ- ment and the utilization process of coal. It has, therefore, become important to have a better understanding of the mineral matter both for coal consumer as well as for coal producer (Singh et al. 2010). Similarly, it is also necessary to know the distribution of environmentally sensitive trace elements in coals of diferent basins (Prachiti et al. 2011; Singh et al. 2015a, b). The commonly occurring minerals in coal belong to alumino-silicates, carbonates, sulphides and silica (quartz). The amount of mineral matter depends on type of deposition, i.e., allochthonous and autochthonous, tectonic framework of the depositional basin, hydrological conditions, climatic conditions, and the geomorphology of the hinterland. Mineral matter in coal may occur in all phases, i.e., solid, liquid, and gas. Lithotype is characterized by types of mineral-rich intergrowths recognized megascopi- cally. Clay minerals, quartz, carbonates, and sulphides are the common minerals found in lignite/coal (Ward et al. 1999; Singh 2004). The occurrence, mobility, concentration, and toxicity of elements directly infuence environment (Finkelman 1995; Dai et al. 2005; Prachiti et al. 2011; Singh et al. 2015a). Elemental analysis of coal is, therefore, impor- tant to formulate the strategies and policies to properly address the environmental problems (Querol et al. 2001; Dai et al. 2005; Wang et al. 2008; Tang et al. 2009; Singh et al. 2012). Coal extraction, preparation, processing and utilization segments of the coal system trigger the envi- ronment related problems particularly due to release of toxic elements along with dust particles and soot into the * Prakash K. Singh prakashbhu@redifmail.com 1 M P Singh Lab of Coal and Organic Petrology, Centre of Advanced Study in Geology, Banaras Hindu University, Varanasi 221005, India 2 Bioremediation Lab, Department of Botany, Centre of Advanced Study, Banaras Hindu University, Varanasi 221005, India 3 Department of Environmental Science, Babasaheb Bhimrao Ambedkar University, Lucknow 226025, India