2012-12-20_GENERAL DOCUMENTS - C1981038

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ground water except during periods of stream flow. The most significant area of alluvium /colluvium occurs in the NW' /4 of Section 13, Township 13 South, Range 92 West (Steven's Gulch wellfield), where a 25- foot -thick sandstone outcrop has created a topographic restriction such that a considerable thickness of alluvial sands and colluvial material has been deposited. Test wells drilled by the applicant indicate that the alluvium in this area can support a pumping rate of approximately 28 gpm (Ground Water Hydrology Appendix, Volume 4). The applicant had installed a production well and used this water for domestic use, dust control, and fire control. The recharge to the Steven's Gulch well field area is through flow from the adjacent colluvial deposits and from a leaky pipeline aqueduct. The ground water flows through the colluvium downslope to the alluvium, where it becomes trapped or temporarily stored. This situation is somewhat modified by the presence of landslide complexes which occur throughout the general area in the Bowie and five adjoining quadrangles (Colorado Geological Survey Information Series 5, 34p.). Ground water will tend to move down through the more permeable material and along lateral shears of these landslide complexes. The sources of ground water discharges from the Steven's Gulch alluvium at the well field are through the applicant's wells, through underflow within the alluvium down the old bedrock channel of Steven's Gulch, and through discharges to the stream during high water table conditions in spring and early summer. Water quality analysis for the Steven's Gulch well water indicates good quality water, with none of the parameters exceeding the recommended standards of the Colorado Department of Public Health and the Environment. Alluvial /colluvial deposits in the Terror Creek drainage near the Morrell Cow Camp are also being utilized for water supply purposes. However, no impact is predicted for these areas since lands affected by mining lie to the south and east. Occurrences of ground water have been noted in the Mesaverde Formation from information obtained from drilling, experience in the mine and from the presence of springs and seeps in the permit area and hydrologically adjacent area. This information indicates that the only potential regional aquifer in the area is the continuous Rollins Sandstone, located stratigraphically approximately 200 feet below the D coal seam. Recharge to the Rollins Sandstone occurs along outcrops and along subcrops beneath the alluvium of Terror Creek to the east and Steven's Gulch to the southwest. However, due to the steepness of the topography in the outcrop areas (i.e. sandstones are cliff formers) and the narrowness of the stream valleys, the Rollins Sandstone receives little recharge. Some recharge to this continuous unit may come directly from the percolation of snowmelt and precipitation downward through fractures. While no site - specific aquifer characteristics for this unit are available from the permit area, indications are that saturated portions of the Mesaverde Formation are not good aquifers (Section 2.04.7, Volume 1). Ground water occurrences in the stratigraphic interval of the Mesaverde Formation above the D seam are a function of the depositional environment and are characterized by saturated horizons of localized lateral and vertical extent, separated by low porosity, unsaturated intervals. These saturated horizons do not appear to contribute significantly to overall regional ground water flow. When in operation, the Bowie No. 1 Mine had experienced maximum inflows of around 1,500 gpd. This inflow came from both the floor and roof and was generally roof drips or wet areas on the floor. Mining progressed below East Roatcap Creek and mine inflows increased but still remained Page 10 of 42