International Journal of Coal Geology, Vol.24, No.1, 259-280, 1993
TRACE-ELEMENTS IN COAL SAMPLES FROM ACTIVE MINES IN THE FORELAND BELT, BRITISH-COLUMBIA, CANADA
Concentrations of Sb, As, B, Br, Cd, Cl, Cr, Co, Cu, F, Pb, Hg, Mo, Se, Th, U and Zn have been determined in channel samples collected at all active mines in the Peace River (northeastern B.C.) and East Kootenay (southeastern B.C.) coalfields. Means in whole-seam samples from both regions (30 samples), excepting those elements which are below detection limits in some samples, are as follows: Sb 1.0 ppm; As 1.6 ppm; Pr 1.0 ppm; Cl 136 ppm; Cr 21 ppm; Co 2.3 ppm; Cu 18 ppm; F 518 ppm; Hg 50 ppb; Th 3.2 ppm; and U 1.8 ppm. By world standards, mean concentrations of Cl, Br, Co, As, Hg and Pb in B.C. coals are relatively low while concentrations of F are relatively high. Mean values of Cl and Th are statistically higher in Peace River coals than in East Kootenay coals; concentrations of other elements are similar in the two regions. Consistent stratigraphic variations in the concentrations of elements generally do not occur, although several of the elements, namely Sb, As, Cr, Co, Cu, F, Th and U, achieve their highest concentrations in the middle one-third of the Mist Mountain Formation ( East Kootenay) and in the upper one-half of the Gates Formation coal-bearing section (Peace River). These trends may be more related to variations in ash content of the samples than to stratigraphic controls. Based on correlations, almost all of the eleven elements whose concentrations consistently exceed detection limit appear to have strong inorganic associations. Exceptions are Cl and Br, which appear to be associated predominantly with the organic fraction.
Keywords:BORON