SW INDIANA COAL CORRELATION USING TRACE ELEMENTS

Correlating coal seams has always been among the most debated and researched issues in coal geology. The correlation is usually conducted using palynology and sulfur and ash content. However, these techniques in most cases do not provide enough information needed for regionally extensive correlations.

The Lower Block coal seam located at the base of the Brazil Formation, Racoon Creek Group, in southwest Indiana and is Bolsovian (Westphalian C) in age. This coal seam represents an economic low to medium sulfur and low ash coal resource which is mainly being used for electricity generation in Indiana. There have been reports that the Lower Block coal is not of the same quality in southern and northern parts of southwest Indiana. Hence it has been suggested by coal exploration and the quality of coal (sulfur content and ash yield) that the Upper Block coal in Clay County coincides with the Lower Block coal from the Daviess County in southwest Indiana. This theory has been tested using the coal geochemistry (mineral content and trace elements) on the Lower Block coals from both Clay and Daviess counties, in the Black Beauty Coal Company mines. Wet sequential extraction of the Lower Block coal was conducted and each fraction was analyzed using an Inductively Coupled Mass Spectrometer (ICPMS) for trace elements. Mineralogy of the samples was determined using X-ray diffraction (XRD). Preliminary results show distinct mineralogical and trace element variation between the Lower Block coal seams from the two counties.