2021-02-05_PERMIT FILE - C1980007A (3)

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West Elk Mize • 3. Bedrock Springs - Springs can be encountered where subsurface formations outcrop. Groundwater moves along the surface of the formation and eventually daylights. Historic Spring Monitoring Data Spring monitoring to establish baseline data and to assess the impacts of mining in the F Seam has been conducted by MCC for over 10 years. Monitoring of springs potentially subject to impact from B Seam mining has been conducted since 1992. The relevant data indicate that F and B Seam mining has had little, if any, impact on spring flows. Specific information on sprint related reining impacts for these seams can be found in the Annual Hydrology Reports from 1982 to the present. Plots of spring flow hydrographs are contained in the Annual Hydrology Reports. Considerable variation from year to year is also apparent along with the seasonal pattern. A comparison of operational data with pre -mining data reveals no discernable difference. Flow monitoring will be continued by MCC in order to assess trends over time. A visual comparison of the data presented in the Annual Hydrology Reports reveals a lack of correlation among spring flows. MCC has been building a representative database for springs in the permit and lease areas, since 1978. Sufficient baseline data, in accordance with CDRMS regulations have been established to enable future determinations as to whether longwall mining could be affecting the springs. As described in Section 2.04.7, the following springs will be added to the monitoring program 10-1, El 4-1, 24-3, and 96-2-2, and Deep Creek Sprung. Conceptual Description of Subsidence Impacts to Springs The key to evaluating whether or not any given spring will be adversely affected by the E Seam mining in the permit area is to define its elevation relative to both the mine seam and the ground surface. Essentially, the higher the elevation of a spring (and spring source), the smaller the probability of adverse impact as a consequence of fractures that extend upward from the mine. However, for a spring to avoid impacts from subsidence, in addition to being above the mine fracture zone, the source of the spring needs to be far enough below the ground surface to avoid surface fractures that may be the result of subsidence. This phenomenon is described by Liane Kadnuck (U.S. Bureau of Mines) in her paper, Response of Surface Springs to Longwall Coal Mining Wasatch Plateau, Utah, where she states, The limited spring response observed at this site may be attributed to several factors; (1) The thickness and composition of overburden present which contained a massive competent sandstone, which causes bridging in the overburden, limiting subsidence, (2) Presence of formations containing swelling clays, and (3) The elevation of the spring above the elevation of estimated heights of fracturing and caving in the overburden." This basic concept is elaborated as follows: In the east panels of the Apache Rocks mining area, only B -Seam mining will occur. Only B -Seam mining will occur m the Box Canyon and West Flat horn rniniing areas. In the Apa=ii2 western panels (Sections 28, 29, and 30), both B and E -Seam mining will occur. Within the Apache Rocks mining area, the overburden thickness for the B -Seam ranges from 600 to 2,20 feet while the overburden thickness range for the E -Seam is 400 to 1,100 feet. The typical interburden distance between the B and E -Seams is 200 feet. Above the LONE and 11NE longwall panels, the 2.05-196 RevisedJune 200.1 PRIG, Jmraary 2006, March 1006; Rev. A4ay 2006 PRIG, Nov. 2006 TR107; Sep. 2007 PR12; Feb 1008 PR12