GENERAL30618 - Laserfiche WebLink

Home Browse Search

-zo- First, the amount of water which percolates into the alluvium is small since the slope of the coal stockpile will favor runoff and since the sediment pond will be dewatered after effluent limitations have been reached. This small amount of affected alluvial ground water will be rapidly diluted by the existing ground water in the system. Estimates made by the applicant, based on a pump test performed on an alluvial well at the site, indicate average flow rates of over 2 million gallons per day in winter months (see "Alluvial Ground Water Hydrology of the North Fork of the Gunnison River - Bear No. 3 Operation" contained in the Bear No. 3 revision application). Second, the identified alluvial valley floor is located more than a mile downstream from the surface facilities area of the Bear Mine. This should be a sufficient distance for the dilution to acceptable levels of any affected alluvial ground water. Third, the potential impact to alluvial water quality will only be short-term. Once mining operations are completed, the coal stockpile and sediment pond at the No. 3 Mine will be reclaimed and the alluvial ground water quality will quickly recover. Surface facilities at the Bear No. 1 and No. 2 portals have been removed, and the area regraded, topsoiled and seeded. Three alluvial monitoring wells have been installed in the North Fork alluvium in order to monitor water levels and water quality both above and below the location of the coal stockpile and the sediment pond at the Bear No. 3 Mine (see Mine No. 3 - Hydrology Map). Baseline and monitoring data for water table depth and water quality has been obtained for the alluvial aquifer (see the above map and "Alluvial Ground Water Hydrology of the North Fork of the Gunnison River - Bear No. 3 Operation"). The wells are being monitored quarterly for all of the parameters listed in Appendix A of the PAR of May 15, 1981. Approximately four years of monitoring data collected from the wells indicate that mining and the surface facilities have not impacted the water quality and quantity of alluvium of the North Fork of the Gunnison River. The potential impacts are considered insignificant, and the applicant's ground water and surface monitoring program should detect any changes in the quantity and quality of ground and surface water supplied to alluvial valley floors downstream. 3. Pursuant to Rule 2.06.8(5)(a)(iii), the Division finds that surface coal mining and reclamation operations will be conducted to preserve, throughout the mining reclamation process, the essential hydrologic functions of the alluvial valley floor. The previous discussion (AVF Finding No. 2 ) identified no potentially significant impact to the AVF. The monitoring plan, as outlined in the application, will ensure that the essential hydrologic functions are maintained.