Abstract: Samples of coal, gangue, roof and floor rocks were collected from the deeply-buried group A coal seam from Huainan
coalfield, Anhui, China. The concentrations of thirteen hazardous trace elements were determined by Inductively Coupled Plasma-Mass
Spectrometry (ICP-MS) to investigate the distribution characteristics of hazardous trace elements in the deeply-buried group A coal
seam of Huainan coalfield. The occurrence of hazardous trace elements in the deeply-buried group A coals were analyzed by the Tessier
five-step morphological extraction method and correlation analysis. The results show that, (1) Compared with the average contents of
various trace elements in the Chinese upper continental crust, the calculated enrichment coefficients of B, As, Se and Cd are all greater
than 1 in the deeply-buried group A coal seam from Huainan coalfield, indicating relative enrichment; the concentrations of B, As, Se
and Cd in the deeply-buried group A coals seam of Huainan coalfield were relatively higher than those in the upper part of the Group B
coals of Huainan, Northern China coals and Chinese coals. (2) Correlation analysis and Sequential extraction experiments show that
most of the trace elements in the group A coals mainly existed in the residual form and Fe-Mn Oxide binding state, and the sum of
quality fractions ranged from 55%~98%. Ni, Mo, Cd, Hg, Cu, Pb and Zn mainly occurred in sulfide minerals, whereas Mn occurred in
carbonate minerals. V, Cr, Se, B and As mainly occurred in clay minerals such as aluminosilicate. (3) Deposition environment of the
deeply-buried group A coals was traced by boron and the results show that the deeply-buried group A coals was formed a brackish
water-influenced sedimentary environment. Concentration of trace elements in the deeply-buried group A coals could be explained by
the stable salt water sedimentation environment and the influence of seawater

Key words: the deeply-buried group A coal seam, hazardous trace elements, concentration, occurrence, depositional environment