2012-04-24_PERMIT FILE - C2009087A (2)

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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 mining - related impacts, and development of any appropriate plans for protection of hydrologic resources and control or mitigation of impacts related to site hydrology. The information presented in this section is based on available published reports and documents; contacts with Federal, State, and local agencies; hydrologic information collected during exploration drilling programs; and the results of ongoing hydrologic monitoring and related sampling and analyses. Copies of hydrologic reports, hydrologic monitoring data, and other relevant hydrologic information are included in Exhibit 2.04.7 -E1, Hydrologic Information. A proposal describing the ongoing hydrologic monitoring program was submitted to and discussed with CDRMS in April 2008 (Twentymile Coal Company, 2008a). Revisions to the monitoring program were submitted to CDRMS subsequently in June 2008 (Twentymile Coal Company, 2008b), and following approval, hydrologic monitoring under the approved plan was initiated that month. The plan proposed collection of groundwater data from 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 monitored initially and, based on 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 (COV2634, 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, SCCC 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 PSCM Permit App. 2.04 -34 Revision 12/17/09