Laserfiche WebLink
-9- <br />Sediment Pond A is designed with an emergency spillway capable of passing the <br />peak flow from a 25-year, 24-hour precipitation event. The sediment pond is <br />not equipped with a principal spillway. Instead, the applicant proposes to <br />install a pumping system to dewater the sediment pond and use the water in the <br />hydraulic mining system. The pumping system is capable of dewatering the pond <br />within 48 hours of the beginning of a 10-year, 24-hour storm event. Sediment <br />Pond A and associated diversions will be retained until revegetation standards <br />are met, at which time they will be reclaimed. <br />The proposed operation is in compliance with the requirements of this section. <br />VI. Water Rights and Replacement - Rules 2.04.7(3) and 4.05.15 <br />The Coal Ridge No. 1 Mine is proposed as an underground hydraulic mine. Large <br />quantities of water will be required in the cutting and fluming of coal. The <br />operation has facilities to recover nearly all of the make-up water, however <br />losses will occur through evaporation, adhesion to coal and refuse, and by <br />seepage into coal, roof and floor rock. The application estimates that <br />approximately 300 acre-feet of water per year will be lost to these processes <br />at a production level of 1 million tons per year. The applicant has purchased <br />sufficient water rights to cover these losses, and has obtained a conditional <br />right for direct removal of Colorado River surface water. <br />Table 3.3-1 of the Permit Revision application lists surface and groundwater <br />rights in the vicinity of the permit area, and Figure 3.3-5 maps the location <br />of those in the immediate area. These sources are located either upgradient <br />from the surface facilities area (in the case of the Riverbend Subdivision <br />wells), or are sufficiently downgradient that any discharge from the permit <br />area would be diluted to background quality prior to reaching them. <br />The proposed operation is in compliance with the requirements of this section. <br />VII. Hvdrolooic Balance: Ground Water - Rules 2.04.5, 2.04.7. 2.05.3(41, <br />2.05.6(31 and 4.05 <br />The application describes ground water occurrence in the permit area and <br />vicinity in Sections 3.3.3 and 3.3.4. Baseline and other supporting data are <br />found in Appendices 3.3-3, 3.3-4, 3.3-5, 3.3-6, 3.3-7, 3.3-8 and 3.3-9. <br />Section 3.3.4.9 discusses the operational ground water monitoring for the <br />site. The application contains sufficient ground water baseline information <br />for the Division to assess the probable impacts of mining on ground water <br />resources. This analysis can be found in the Probable Hydrologic <br />Consequences/Cumulative Hydrologic Impact Study section of this document. <br />The current ground water monitoring system is described on pages 4-80 to 4-82 <br />and consists of 6 alluvial wells located in and near the surface facilities <br />area. The applicant has committed to drilling of an additional well <br />downgradient from Sediment Pond A. These wells are currently sampled <br />quarterly for field parameters and annually for chemical parameters listed in <br />Table 4.6-1. NCEC has committed to a monthly field parametersjquarterly <br />chemical sampling frequency prior to the mining of any coal. <br />