Figure 3

(a) Correlation between the intercept values obtained from log function regression for the geochemical effect of lanthanides in the C2 coal seam in Fengfeng Mine of Handan Coalfield in Hebei Province and the total concentration of REE, and (b) the correlation between the regression coefficients and concentration of LREE. The original data of REE refer to Table 1 (Dai Shifeng, 200710), the regression coefficients refer to Table 2.