Geochemistry of the No. 6 coal seam of the Guanzigou Mine, Inner Mongolia, Northern China

To study the geochemical characteristics of the No. 6 Coal of the Guanzigou Mine, the contents of major and trace elements were determined by X-ray fluorescence spectrometry and inductively coupled plasma-mass spectrometry. Results showed that the contents of SiO2, Al2O3, TiO2, Li, Ga, In, and Pb in the No. 6 Coal are higher than the common contents of the average values in Chinese coal, whereas those of other elements, such as Co, Ni, Rb, Cs, and Ba, are lower. The SiO2/Al2O3 ratio (1.22) is close to the ratio in pure kaolinite (1.18) because of the lower proportion of quartz or boehmite in the coal. In the vertical section, all major and most trace elements in the samples are enriched near the parting and floor. The contents of Al2O3, Li, and Ga have reached their minimum mining grade, supporting their recovery as by-products. The high content of Pb should be paid attention to during coal mining and utilizing. The geochemical associations of the elements were assessed according to correlation and cluster analyses. It was found that Al2O3, SiO2, Li, Na2O, Bi, MgO, K2O, Rb, Cs, and Ga are associated with clay minerals. Cd, Pb, TiO2, and Cu are associated with unidentified traces of sulfide minerals or organic matter. In, Tl, MnO, Co, S-td, Fe2O3, and CaO are associated with sulfides, carbonates, or organic matter. P2O5, Sr, Be, Ba, Ni, and U are associated with gorceixite or goyazite. These results not only provide fundamental information on coal seam formation, but also favor the comprehensive utilization of the coal and the assessment of environmental and health-related effects of the coal during mining and utilizing processes.