Laserfiche WebLink
broad, asymmetric syncline whose axis trends north-south. Previous mining at this site was <br />entirely within the Allen seam, stratigraphically located in the Raton Formation. The Poison <br />Canyon Formation unconformably overlies the Raton Formation. The Poison Canyon <br />Formation has a thickness of approximately 200 feet and occurs only as small, isolated <br />outcrops above an elevation of 8,000 feet. Unconsolidated quaternary alluvial and colluvial <br />deposits overlie the Raton Formation in the low-lying areas. <br />The rock strata dip approximately two degrees to the north-northeast. The permit area <br />contains one steep, normal fault trending east-northeast with vertical displacement less than <br />25 feet. The Allen Seam lies from 450 to 900 feet below the surface. Immediately above the <br />coal are interbedded sandstone, siltstone, and shales. Interbedded sandstones, shales, and <br />siltstones also underlie the seam. <br />The alluvium of the Middle Fork of the Purgatoire River is a significant aquifer in the permit <br />and adjacent areas. The Purgatoire River originates several miles west of the mine in the <br />Sangre de Cristo Mountain Range. It flows into the Arkansas River near Las Animas, <br />Colorado, approximately 120 miles northeast of the mine. <br />Portions of the Apache Canyon, Pete Canyon, and Ciruela Canyon drainages are found within <br />the mine permit area. These basins contain intermittent and ephemeral streams that flow <br />predominately in response to runoff from snowmelt during the spring and intense rainfall <br />during the summer. A portion of the flow in intermittent drainages is sustained by groundwater <br />discharges. Pete Canyon is tributary to the North Fork, while Apache and Ciruela Canyons <br />are tributary to the main stem of the Purgatoire River. <br />The region is characterized by a semi-arid climate. The prevailing wind is from the southwest <br />and average annual precipitation is 16.92 inches. The length of the growing season in the <br />area varies from 90 to 110 days. <br />Vegetative communities in the area of the mine can be separated into two physiognomic <br />types: the low grassland and riparian communities along the Purgatoire River valley bottom, <br />and forest communities dominating the slopes and upland areas along the river valley. <br />Communities on the north-facing slope and the river valley were inventoried and found to <br />contain four distinct vegetative communities at the New Elk Mine area: a Ponderosa pine- <br />Douglas fir-oak community, a Ponderosa pine-oak community, a grassland community, and a <br />riparian willow carr community. The Ponderosa pine-Douglas fir-oak community is found on <br />the north-facing slope above the mine facilities at elevations above 7,600 feet. The overstory <br />consists of mature Ponderosa pine and Douglas fir with interspersed pinon pine and Rocky <br />Mountain juniper. The dominant shrub species is Gambel's oak. Cover is relatively sparse <br />(12 percent) and productivity is low (62 lb/ac). The Ponderosa pine-oak community occurs on <br />the north facing slopes above 7,500 feet on the eastern two-thirds of the permit area. Pure <br />Ponderosa pine stands are interspersed with Gambel's oak, pinon pine, and Rocky Mountain <br />juniper. Vegetative cover is low (4 percent), as is productivity (44 lb/ac). The grassland <br />community was inventoried at the adjacent Golden Eagle Mine on a plateau above the river at <br />7,200 feet elevation, since no undisturbed grassland communities could be found at the New <br />Elk Mine. Dominant grass species were blue grama and western wheatgrass, with many other <br />4