Rare earth elements and yttrium in Pennsylvanian coals and
Nov 01 2020· Coal mines and coal beds were selected to provide samples of the largest and most heavily mined Pennsylvanian coal beds Raccoon Creek and Carbondale Group in Indiana Four marine shales selected for this study are associated with the coals Sh1 informally called the Veale shale in this paper occurring above the Viking A Coal in the