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<br /> <br />A. Geology - <br />The principal structural feature of the region is the Raton Basin, a <br />broad, asymmetric synclinal basin with an axis trending north-south. The <br />western limb is gently dipping in the study area. Steeper eastern dips <br />are found west of the mine, outside the study area. The Raton Basin was <br />formed during the latter phases of the La ramide Revolution when the <br />Sangre de Cristo Range was thrust eastward. <br />The applicant submitted geologic maps (Map 5) and geologic cross-sections <br />(Map 6) with the renewal application. The Golden Eagle and New Elk Mines <br />are located on the western limb of the Raton Basin. The dip of the <br />strata is 2° to the northeast in the general area of the mines. The coal <br />seam at the western limit of the New Elk Mine has a dip which increases <br />to 14° to 16°. <br />Several steep, normal faults, trending east-northeast have been mapped <br />between Weston and Starkville (Wood, et al., 1957). Numerous faults have <br />been mapped in the New Elk Mine workings. These faults are all high <br />angle faults (almost vertical) and have low displacements. The maximum <br />measured displacement of faults in the New El.k Mine workings is between <br />15 and 17 feet. Most faults pinch out within a very short distance. <br />There are two major faults in the area which are extensive. They strike <br />N80oE. One significant fracture zone has been encountered in the <br />Golden Eagle Mine in the area of the Second Right entries. Displacement <br />by the apparent fault associated with this zone may be approximately <br />30 feet. (See pages 2.04-7 through 21 of renewal application). Also <br />there is a fault identified by WFC on Map 5 (Geology). <br />The stream valleys overlying the existing New Elk Mine workings do not <br />appear to be fault-controlled. No extensive faults were encountered in <br />the mine workings under the Middle Fork of the Purgatoire River, <br />Pete Canyon, or Apache Canyon. <br />Other than that encountered in conjunction with a significant water flow <br />in the Second Right entries, no faulting has been encountered in the <br />Golden Eagle workings. <br />Rock units in the Raton Basin range in age from Pre-Cambrian to <br />Quaternary. The stratigraphy of the study area consists of the <br />Trinidad Sandstone, the Yermejo Formation, the Raton Formation, and the <br />Poison Canyon Formation. <br />The Trinidad Sandstone is the oldest and deepest of the sedimentary <br />formations listed above. The Cretaceous age Trinidad Formation is a <br />massive intertongued sandstone which is an important marker strata in the <br />Raton Basin. The sandstone is fine to very fine-grained, light gray to <br />buff in color, and is slightly arkosic. The Trinidad Sandstone reaches <br />thicknesses of 250 feet in the general area and is a prominent cliff <br />former. This sandstone is separated from the coal seams by up to <br />900 feet of interbedded shales, siltstones, and sandstones. <br />-9- <br />