Laserfiche WebLink
and sub-bituminous. Although the Twenty <br />noted within the Williams Fork Formation in <br />a fades change within the Williams Fork <br />Sandstone in the Danforth Hills Area. <br />Structure <br />N1ile Sandstone Member is a regional aquifer <br />the Craig, Hayden and Steamboat Springs area, <br />Formation has eliminated the Twenty Mile <br />The area around the mine is dominated by the Axial Basin Uplifr, an anticline, or arch, which <br />is a southeastward extension of the larger Uinta Mountain Arch. The Axial Basin anticline is <br />an asymmetrical fold, the axis of which trends north 60° west, with strata dipping (inclining) <br />steeper on the south side of the axis than on the north. The south flank of the anticline has <br />several secondary folds trending subparallel and at approximate right angles to the main <br />anticlinal axis. In general, the rocks of the broad anticline have not been stressed sufficiently <br />to cause them to break severely, but a few discontinuous normal faults trending primarily <br />parallel to the anticlinal axis are found in the area. <br />The stricture of the petmii area is geologically simple. The axis of the Collom syncline, a <br />downward fold, passes through the permit area as shown on the Geology Nlap (Map 7). <br />Bedding orientation, as measured on surface outcrops, generally has a strike of N 70° W and <br />is characterized by dips from nearly horizontal to as much as 20 to the north. As the mine <br />advances southward, the structure is influenced by the Elkhorn Syncline and a change in <br />attitude of the structure occurs resulting in an eastward dip and nearly north-south strike. <br />Local deviations in this general trend are the result of discontinuous minor folds resulting <br />• from differential compaction. <br />During geologic mapping, there was no evidence of faulting in the rock units within the <br />mining area; however, some linear features that may be fault controlled were observed on <br />aerial photographs of the property. Such lineations may also be related to joints (fractures <br />without appreciable movement) in the rock. Three major joint trends that generally coincide <br />with these lineations were observed within the permit area. These are nearly vertical or <br />vertical and strike approximately north 70° west, north 45° west, and north 30° east. In <br />surface exposures, sandstone exhibits <br />• <br />2.04.6-5 <br />