2016-01-07_PERMIT FILE - C2010089A (3)

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From the work that has been done, it appears that another nest of 3 monitoring wells is warranted. The monitoring site would be located in the southwestern portion of the permit area and would be located immediately down gradient from the limit of mining disturbance. Therefore, 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. It is anticipated that these wells will become the points of compliance after review of additional data and consultation with DRMS. Overburden Zone Ground Water Ouality Water level monitoring and the piezometric maps show the nearly immediate response of most of the nine new monitoring wells to the seasonal surface irrigation with water levels going up and down corresponding to the periods when water is in the 2nd Park Lateral Ditch. The impression is that the Overburden Zone is annually being flushed with relatively good quality irrigation water. This further suggests that water quality would improve during periods of irrigation and deteriorate during periods when the ditch is dry. However, comparison of the ground water quality data (see Appendix 2.04.7-1) with the water level data reveals no such correlation. Table 2.04.7-1 is a summary of the water quality analyses for the Overburden Zone, showing the minimum, maximum and average values of the analyzed parameters. No data for overburden monitoring well GW -N55 is shown as this well was nearly dry to the point that there was not enough water to collect water samples. The summary of the analyses for wells GW -N49 and GW -N52 are also compared with the WQCC (Regulation 41, The Basic Standards for Ground Water) drinking water and agricultural quality standards. The results show the overburden water quality to be unsuitable for domestic drinking water primarily for sulfates. With the exception of calcium and bicarbonate, the water quality at GW -N52 is better than that at GW -N49, most probably the result of being located closer to the seasonal more alkaline recharge from the 2"d Park Lateral irrigation ditch. The values for pH at GW -N52 are also somewhat higher (more alkaline). Again, suggesting that being closer to the main source of recharge (the ditch) affects the water quality to a greater extent at GW -N52 than at GW -N49. Coal Zone Ground Water Quality Quarterly groundwater quality samples were collected from the three wells (GW -N48, GW -N51 and GW -N54) beginning on October 10, 2008. The groundwater quality data is contained in Appendix 2.04.7-1 along with the water level and graph information. Review of the coal zone quality does not clearly reveal any correlation with the irrigation seasons, although there is a slight increase in Ca, CaCO3' SO4 and total dissolved solids (TDS) during the winter months when the ditch is not running. It may require a few more seasonal irrigation cycles to validate this initial impression. Again, the monitoring well located furthest up - Section 2.04.7 Page 9 Sept. 2015 (TR -11)