1994-10-21_GENERAL DOCUMENTS - C1980007

Home Browse Search

Consequences of Mining" section of this document and the "Cumulative Hydrologic Impact Study" document for this mine area. The ground water systems relevant to mining activities in the region are the alluvial deposits associated with streams and the Mesaverde Formation. Ground water use in the general area around the West Elk Mine is confined to shallow wells in the alluvium and Rollins Sandstone of the North Fork of the Gunnison River and its tributaries. The west Elk Mine's experience in mining the F and B seams indicates that ground water inflows are associated with fractures near the subcrop and are seasonal. Evidence suggests; that ground water movement is controlled largely by fracture patterns and topography. There are seven categories of potential aquifers that occur in the Somerset Coal Field. These are: 1) the alluvial and terrace deposits associated with the North Fork of the Gunnison River; 2) the localized, shallow alluvium along creeks tributary to the North Fork; 3) the discontinuous, lenticular and laminar sandstones of the Mesaverde Formation; 4) the Rollins Sandstone; 5) the coal seams; 6) shallow colluvial surficial deposits; and 7) fracture zones in bedrock. The most continuous sandstone aquifers of any significance in the region are the Rollins Sandstone and the massive sandstone separating the upper and lower Coal members of the Mesaverde Formation. However, the latter massive sandstone produces very little water, as evidenced by the dryness of the Bear Mine and the lack of springs associated with this unit. The Mesaverde Formation tends to be dry, or the rock units are of such a low permeability, they yield insufficient water for sustained use or mine discharge. The sandstones are lenticular and discontinuous and are usually highly cemented. A description of the surface: water system can be found in Section 2.04 .7 of the permit application. Supporting information is contained in Map 34, which illustrates the drainages associated with the WEM coal lease area, Map 37 and 37A, which delineates the location of all known springs on the coal lease area, and Map 36, which shows the reservoirs and irrigation ditches associated with the Minnesota Creek Basin. A description of the surface water occurrence and mining impacts on adjacent areas can be found in the "Probable Hydrologic Consequences of Mining" section of this document, and the "Cumulative Hydrologic Impact Study" document for this mine area. All of the streams draining the West Elk Mine permit area are tributaries to the North Fork of the Gunnison River. Sylvester Gulch, Lone Pine Gulch, and Gribble Gulch are ephemeral streams draining the northern portion of the lease area. Minnesota Creek and :its tributaries, Horse Creek, South Prong, Lick Creek, Dry Fork, and East Fork, drain the southern portion of the coal lease area. Minnesota Creek enters the North Fork of the Gunnison River near Paonia. The overall drainage exhibits a dendritic drainage pattern with steep channels. Horse Creek and South Prong of the East Fork of Minnesota Creek are perennial streams, while Lick Creek, Upper Dry Fork, Sylvester Gulch and Gribble Gulch are ephemeral streams. Minnesota Reservoir controls much of the flow in the lower Dry Fork of Minnesota Creek, and Beaver Reservoir controls the flow in the East Fork of Minnesota Creek. Lone Pine Gulch has no evidence of recent flow; therefore, no gaging station has been constructed. Even when all of the six gaged watersheds were found to be flowing, Lone Pine Gulch showed no flow or evidence of flow. Geolocry - Rules 2.04 .5 and 2.04 .6 The applicant describes the geology of the permit and adjacent area in Section 2 .04 .5 of the permit application. Additional information is detailed on Map 9 and 9A, which details the geology of the lease area, as well as the coal outcrop line and the strike and dip for the F and B seams. Stratigraphic cross-sections are shown on Maps 10, 11, 11A, and 12 . 6