2012-01-13_APPLICATION CORRESPONDENCE - C2010089 (2)

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C -2010 -089 PARNos. 1- 1A -1B, 2- 2A -2B, 3 New Horizon North Mine Page 15 of 60 The statement on page 2 was not corrected as requested. Please correct the statement on page 2 as follows: "Typical completion diagrams one each for the overburden, coal zone, and underburden well completion monitoring, zones are provided in Figure 1 of Appendix 2.04.7 -1." Iteiit t'e,soh7c d itt Dt-, - i1 rc* l)ott ip 2. The application should contain the specific well completion information for each of the nine new monitoring wells. Table 1 in Appendix 2.04.7 -1 is titled "Proposed Ground Water Monitoring Hole Locations and Depths and contains "Estimated Monitoring Hole Depths This table should be replaced since the wells have been drilled and constructed. Please add a well completion information table to Appendix 2.04.7 -1 that at a minimum contains the following information for each monitoring well: well identification/location, formation monitored, total depth, well casing type and diameter, ground elevation, casing stickup or measuring point elevation, and slotted interval. The information was not incorporated as requested. Table I in Appendix 2.04.7 -1 has not been changed. The application should contain the specific well completion information for each of the nine new monitoring wells. Table 1 in Appendix 2.04.7 -1 is titled "Proposed Ground Water Monitoring Hole Locations and Depths" and contains "Estimated Monitoring Hole Depths ". This table should be replaced since the wells have been drilled and constructed. Please add a well completion information table to Appendix 2.04.7 -1 that at a minimum contains the following information for each monitoring well: well identification/location, formation monitored, total depth, well casing type and diameter, ground elevation, casing stickup or measuring point elevation, and slotted interval. Itent rc soh,ed in Dee-2011 msj)onse 3. There is atypographical error on page 2. In the second paragraph, WFC states that "...water quality monitoring began immediately upon completion of these 9 holes on October 10, 2010." This should read "October 10 2008 ". hertz resoh, d in tt120_11 response. 4. Groundwater recharge and discharge are described on page 4 and piezometric level maps are provided for each zone (overburden, coal, and underburden) from which flow direction can be ascertained, but there is no specific description of groundwater flow direction and groundwater discharge is described only in general terms. The Division agrees with the general description provided in that the overburden strata is the primary source of discharge to the drainages of Tuttle Draw (to the south) and Coal Canyon (to the west) and that the permeability and porosity will increase with spoil replacement. WFC states that "discharge is down dip to the outcrops (and old Peabody high -wall) of the stratigraphic zones ", but no specific information is given. Discharge rates and flow direction are very important for determining probable hydrologic consequences and the Division believes that these sections on page 4 should be further clarified and substantiated as follows. Reference is made to the New Horizon 2 permit and calculations using Darcy's law are quoted. This information provided is not very useful because the values given require site - specific information including: hydraulic conductivity, gradient, and cross- sectional area which may not be directly applicable to the New Horizon North Mine. Please re- evaluate this information and provide a description of flow direction and gradient for each monitoring zone. Please also describe how the data were obtained for calculating the discharge rates provided (i.e., slug test, pump test etc.). If applicable these data may be useful for predicting or estimating discharge rates for New Horizon North Mine with