2017-08-16_PERMIT FILE - C2010089A (4)

Home Browse Search

developed to assess the possible impacts to the hydrologic system. The results of the monitoring programs have and will continue to be employed to detect changes to the hydrologic balance and if detected significant changes can then be mitigated by changes to the operations. The approved monitoring program is described in Section 2.04.7, Hydrology Description. This program will continue for the foreseeable future until amended with approval of DRMS. Groundwater Monitoring Plan Ground Water Quality Monitoring data on ground water quality will be compared against the multiple year baseline monitoring ranges established for each chemical parameter monitored at each site. Because a number of variables can affect water chemistry, only significant increases or consistent trends will be considered as possible impacts from mining. After permit approval and prior to new disturbance, three (3) new ground water monitoring wells were installed in the southwestern portion of the NHN permit area. The locations of these 3 new wells are shown on Map 2.04.7-1. New ground water monitor well GW -N56 will monitor the underburden (UB), well GW -N57 will monitor the coal zone (Coal) and well GW -N58 will monitor the overburden. GW -N56 was completed on August 8, 2012 while GW's N57 and N58 were completed on August 9, 2012. The completion diagrams for the three new monitor wells are shown on Figure 3 of Appendix 2.04.7-1. These wells will be monitored and reported on the same cycle as the other ground water monitoring wells. After review of additional data and consultation with DRMS, ground water monitoring wells GW -N56, GW -N57, and GW -N58 have been designated as points of compliance. Ground Water Quantity Future drawdowns in the overburden, coal and underburden zones will be compared against multiple year pre -disturbance (baseline) average water level fluctuations. Water level fluctuations as a result of irrigation, natural and water quality sampling stresses have been reasonably defined. Significant water level drops outside these multiple year ranges will be considered to be possible effects from pit pumpage. Water level drops in monitoring wells outside the projected zones of pit pumpage drawdown will be considered suspect unless a consistent deepening trend develops. Surface Water Monitoring Plan Surface Water Quality Future impacts on surface water quality will be evaluated by trend analysis. Mining activities at the New Horizon #1 Area began prior to the onset of collecting surface water quality data (1979), hence, no true baseline data exists for comparison purposes. However, a well-documented but short record of surface water quality has been collected during baseline studies conducted at the New Horizon North area. Regardless, the significance of impacts will be evaluated by analyzing for prominent trends of changing chemical concentrations Section 2.05.6(3)(b)(v) Page 5 December 2016 (RN -01)