2010-02-09_PERMIT FILE - C1982056A (6)

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and azsociated spoil material created from past surface mining activities, the likelihood of creating acid producing spoil is low. 2.04.7 Hydrology Description (1) Ground WaterLrforma[ion (a) The application shaft contain a description of the ground water hydrology for the proposed permit and adjacent area, including, at a minimum: (i) The depth below the surface and [he horizontal extent of [he potentiometric surface of each aquifer above, within and, if potentially impacted, below the lowest coal seam to be mined; (iij The lithology and thickness of the aquifers; (iii) The seasonal quantity and qualit)~ of the water within each aquifer; (iv) Ownership, uses and location information for all existing wells, springs and other developed water resources; and (v) The quality of the subsurface water. Water quality sampling and laboratory analyses will be conducted in accordance with 2.03.3(4) and shall include: (A) Total dissolved solids or specific conductance corrected to 25 C; (B) pH; (C) Total iron; and (D) Total manganese. RESPONSE The responses presented below reflect the information presented in the original application and subsequent • submittals for the Southwest Mining District and Eastern Mining District. The information for the subsequent submittals is contained under the title for that district. It should be noted that the ground water basin in which the mine is located is the same for all of the districts; therefore, the discussions presented in the original application are pertinent to the expanded areas. The discussions have been updated to reflect the passage of time since the original application was submitted. The Foidel Creek mine is located at the southern end of the Eckman Park sub-basin on the southwest flank of the locally significant Twentymile Park structure of the Twentymile Park Basins results ins the enclosed ground water basin which is rimmed by outcrops of the major lithologic units described in Section 2.04.6, Geology Description. The limits of the potential mining related impacted on the ground water system are shown on Map 4, Proposed Hydrologic Area Boundaries. Ground water in the Twentymile Park Basin exists primarily under confined conditions within the bedrock units and under unconfined conditions within the alluvial materials underlying the major surface drainages of the area and backfilled areas of adjacent surface mined areas. Ground water occurrence and movement within the bedrock aquifer system is controlled by geologic structure and lithology, and to a limited extent, by mine related disturbance. Recharge to the major aquifer units occurs in the area of outcrop primarily in the southern and western margins of the Twentymile Park Basin where unconfined conditions may exist locally. Ground water movement tends to follow the structural dip of the lithologic units toward the basin axis. This results in confined aquifer conditions down gradient from the outcrop area due to the presence of relatively low permeability shale and interbedded siltstone/shale units within the lithologic sequence. Significant artesian pressures in the central part of the basin also exist as a result of the structural control of ground water movement. • The major bedrock aquifer units with the Twentymile Park Basin are the regionally extensive Twentymile and Trout Creek sandstones. The Wadge Overburden sequence contains ground water, but it is not utilized as a water supply except in dust control by TCC. As will be described in following sections the Wadge Overburden interval APPeZC±L'~v APR t 2000 Permit Renewal No. 3 2.04-19 12/10/98