Geochemistry of late Permian Coals from the Yantang Mine in Xuanwei, Yunnan, China
16 samples included coals, roofs, floors and tonstein of Late Permian collected from Yantang mine, Xuanwei were characterized through a petrographic and geochemical investigation. The results showed that, Yantang coals are medium degree of coalification bituminous coals; between gas coal and rich coal; have middle to high ash yields; extraordinarily low sulphur except B2-4, and dominanted by pyritic sulphur. Yantang coals are mainly composed of vitrinite and inertinite. The major minerals are clay minerals and quartz, followed with calcite, pyrite, illite and so on. The contents of Cu, W, Zr and V in Yantang mine were higher than the coals of national and Permian of southern China. Pearson correlation analysis results show that Be, Ni, Tl, Th, Li, Ga, Cs, Zr and Hf and ash yields significantly related at the 90% confidence level (r=0.51-0.79), and it indicate the nine elements are combined in minerals in the coal or related with minerals closely.