COMPARISON OF COAL COMPOSITION AND ELEMENTAL DISTRIBUTION IN SELECTEDSEAMS OF THE SYDNEY AND STELLARTON BASINS, NOVA-SCOTIA, EASTERN CANADA

AbstractSelected high to medium volatile bituminous coal seams of Carb oniferous age from the Sydney and Stellarton Basins, Nova Scotia, East ern Canada were analyzed for their organic and inorganic components. T hese studies evaluated: (a) the evolution of the ancestral mires (coal facies) that formed various seams; (b) the lateral and vertical distr ibution of various elements within coal facies (lithotypes); and (c) t he mode of occurrence of various elements. Coal facies fluctuated betw een rheotrophic and minerotrophic mires with occasional flooding or dr owning of the mire forming inorganic partings. These partings are the source for most lithophile elements including B, Cr, U, V, and rare ea rth elements. Most of the lithophile elements are associated with a di stinct, mainly syngenetic, mineral phase (associated with the clay min erals), which is derived from the erosion of a hinterland source. Chlo rine, Ca and minor amounts of As and Mn are organically bound. Arsenic is mostly associated with fine-grained framboidal pyrite as solid sol ution. Other chalcophile elements such as Cu, Pb, and Zn in the Sydney Basin occur as a syngenetic sulfide mineral phase, whereas these elem ents in the Stellarton Basin are associated with syngenetic and epigen etic sulfides. Arsenic, Cl, and Mo and part of the Cu and Pb are possi bly derived from a mineralized brine that was originated from the diss olution of Windsor Group evaporites. The lateral variation of elements suggests that the coal beds in the Sydney Basin are enriched in As, C I, Mn, and Pb whereas those of the Stellarton Basin are enriched in Cr and Ni. The Donkin resource block of the Sydney Basin has the lowest concentration of As, Mn, Ni, and Pb, which make it attractive from a d evelopment perspective. (C) 1998 Elsevier Science B.V. AU rights reser ved.