2013-04-18_PERMIT FILE - C2009087A

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RULE 2 - PERMITS 2.04.7 Hydrology Description This section of the permit application describes site - specific hydrologic conditions including seasonal variability within the mine permit and adjacent areas. evaluation of potential minill`Ll- related impacts. and development of an} appropriate plans for protection of hydrologic resources and control of mitlgatlon of impacts related to site IiNldrology. The information presented in this section is based oil available published reports and documents, contacts with federal. State. and local agTencies: hydrologlc information collected during exploration drilling programs: and the results Of ol10olllg hydl'ologlC Illollltol'im, aIld related salnplillg and analyses. Copies of hydrologic reports. hydrologic mollltorillg data. and other relevant hydrologic information are included in Exhibit 2.04.7 -E1, I lydrologic Information. A proposal descrlbim, the ongoing hydrologic inollltorlll" 111,001'arn was submitted to and discussed with CDRMS in April 2008 (Twentymile Coal C'onlpan}. 2008a). Revisions to the monitoring program were submitted to CDRMS subsequently in .Tune 2008 (Twentynlile Coal Company, 2008b), and followingT approval. hydrologic monitoring under the approved plan was initiated that month. The plan proposed collection of groundwater data froin eight existing monitoring wells and five proposed new monitoring wells completed in the Wadge Overburden. Wadge Coal and Wadge UnderbUrden. The eight existing monitoring wells were to be monitoI'ed initially and. based oil the results; four were to be selected for baseline data collection. Proposed monitoring included monthly collection of water level data and quarterly collection of water quality samples including field parameters for the one -year baseline data period. The sampling and analysis protocols were in accordance with CDRMS guidance, with laboratory analyses following Table 1 of' the CDRMS Guidelines for the Collection of Baseline Water Quality and Overburden Geochemistry Data. Four of eight existing monitoring wells proposed for baseline data collection purposes (C'OV2634. CW2635, COV2636, and CW2637) were deemed inoperable due to anomalous water levels and suspected screen failures that were found during initial sampling efforts. The plan proposed using surface water data collected during the ongoing Seneca Coal Company's monitoring program for the Seneca II mine and existing data collected during monitoring for the Yoast mine. The data set includes many years of tri- annual monitoring for flow and water quality (field and laboratory) at stations on Grassy Creek and Little Grassy Creek. An inventory of springs and seeps along the proposed haulroad and mine access route that were being contemplated at the time and portal area was also included. However, the proposed haulroad and mine access route to the south have since been removed from the operations plan, and the Seneca II permit information contained sufficient information on seeps and springs in the vicinity of the portal to not warrant performing this inventory. As requested by CDRMS, PSCM conducted a field inventory of springs and seeps within and adjacent to the permit area in August of 2009. Spring and seep data collected during the August inventory are included in Exhibit 2.04.7 -E1. Groundwater Information The following subsections present current information on the occurrence, quantity, quality and use of groundwater in the mine permit and adjacent areas. Beneficial use of groundwater within these areas is minimal due to the limited availability and quality, and the relatively great depth to groundwater. Given these considerations, the significance of groundwater resources relates to potential impacts on mining operations of groundwater inflows; potential mining- related impacts on seeps and springs which may be utilized in conjunction with post - mining land uses; and the quantity Midterm Review 2.04 -34 Revision 04/2013