Coal resources of the Henry Mountains coalfield (OFR-362)

By: D. E. Tabet

This study builds on the work of various previous investigators and includes new data from outcrop studies carried out by UGS personnel during the late 1980s as well as recently released coal company drilling and coal-quality data. The coal outcrop traces, as mapped by the UGS on 7.5 minute quadrangles, were digitized and then recompiled at a 1:100,000 scale. Coal thickness measurements from outcrops were plotted on the maps only when they appeared to fully represent the complete coal section for each coal zone and not just scattered individual coalbeds. Published, as well as newly released, coal exploration drilling data were plotted with the outcrop data to produce field-wide total coal zone thickness and depth to coal maps for the Ferron and Muley Canyon Sandstone coal zones. Finally, coal resources were calculated using the demonstrated, inferred, and hypothetical data-spacing reliability categories developed by the U.S. Geological Survey.

Demonstrated resources lie within 3/4 of a mile of point of thickness measurement, inferred resources are between 3/4 and three miles from a thickness measurement point, and hypothetical resources lie more than three miles from a thickness measurement point. The resources were also classified using the following depth categories: less than 100 feet of cover, 100 to 1,000 feet of cover, and 1,000 to 2,000 feet of cover. No coal resources in the Ferron Sandstone and Muley Canyon Sandstone members of the Mancos are known to lie below 2,000 feet of cover.

Other Information:
Published: 1999
Pages: 32 p.
Plates: 6 pl.
Scale: 1:100,000
Location: Garfield and Wayne Counties
Media Type: Paper Publication