HYDRO29436 - Laserfiche WebLink

Home Browse Search

~- Jon C. Kubic October 20, 1998 Additional monitoring/observation wells in the Elk Creek drainage are being considered to further evaluate the groundwater potential for the D-Seam. In preparation for construction of initial mine development, a series of five geotechnical holes are planned. Wells will be installed in some, or all, of the geotechnical drill holes. Additional data will be collected to further define the aquifer coefficients, and predict the water yield and recharge capacity, for the D-Seam. At the present time, it is anticipated there will be a requirement for mine water discharge from the new Elk Creek Mine. The evaluation should be able to quantify the expected mine water discharge. Also, it is anticipated there will be a requirement for dewatering of the D-Seam, prior to, and during construction of, the initial mine development. Dewatering of the D-Seam would be accomplished with the use of dewatering wells in the vicinity of the initial mine development area. Subject to completion of the evaluation, it is initially anticipated three dewatering wells will be required, each capable of producing between 200 and 300 gallons per minute. Following construction of the initial mine development, underground sumps will be installed, similar to the existing system in the Sanbom Creek Mine. Water quality monitoring to date indicates the water quality from any dewatering wells, and future mine water discharge from the Elk Creek Mine, will be similar to the wells and the current mine water discharge from the Sanborn Creek Mine. Water quality data for the Sanbom Creek Mine discharge, Outfall O11 are attached. High levels of total dissolved solids (TDS), typical for all groundwater in this area of Colorado, has been well documented for the Sanborn Creek Mine discharge. After extensive study of the condition, including the Aquatic Impairment Study of the Sanbom Creek Mine Discharge, Somerset, Colorado, by John C. Emerick, Nevis E. Cook, and Susan M. Hoffineister, Division of Environmental Science and Engineering, Colorado School of Mines, Golden, Colorado, January 30, 1995, it has been concluded the mine water discharge has a minima] impact on the North Fork of the Gunnison River. As a result of these studies, the Whole Effluent Toxicity (WET) test requirements for the Sanbom Creek Mine have been modified to a single species test with Fathead minnows. Prior to starting any dewatering activities from the D-Seam for construction of initial mine development, and to be prepared for future mine water discharge for the new Elk Creek Mine, we will require an amendment to our current discharge permit. All dischazge from dewatering wells, and mine water from the future sumps, will be combined into a single discharge point into Elk Creek. Elk Creek has been classified as an intermittent stream. Baseline data from 1980 to 1982, and recent sampling in 1998, for two sites, one downstream from the surface facilities area, and one upstream from the surface facilities area, are attached The lower reach of Elk Creek is contained in a series of culverts under the surface facilities area, the railroad, and State Highway 133 before entering the North Fork of the Gunnison River. 2 XB~w