Geochemical evaluation of coal from the Tertiary Usibelli Group, Usibelli mine, Alaska, one of the lowest sulfur coals mined in the United States

The Nenana coal basin extends 240 km in length and 1.5-50 krn in width along the northern foothills of the Alaska Range in central Alaska. Located at the western end of the Nenana basin is the Usibelli Coal Mine, approximately 120 km southwest of Fairbanks. The Tertiary Usibelli Group consists of coal-bearing fluvial and lacustrine sedimentary deposits that were derived from the Yukon-Tanana Upland area located northeast of the present mine site. To evaluate changes in major-, minor-, and trace-element distributions, we collected 65 samples from the No. 3 bed from 5 different locations and 128 samples from the No. 4 bed from 6 different locations