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dewatering of these private wells. According to Exhibit K, the mine will act as a <br />dewatering well and could potentially impact wells adjacent to areas undermined and <br />subsided. Analysis should include cross sections through registered wells, especially those <br />wells upgradient in Chandler Heights. (Rule 2.04.7(1)(b). <br />I5. Please submit completion diagrams for the monitoring wells included in the hydrologic <br />monitoring program. The State Engineer also requires that monitoring wells be permitted <br />with the Division of Water Resources. Please submit copies of monitoring well permits for <br />incorporation into the permit application. It may be convenient to combine the afore- <br />mentioned materials into one new exhibit to the permit. <br />16. Exhibit K states that "water quality will not be sign~cantly diminished by mining activities <br />and mine openings because ... (2) the low permeability of the Vermejo Formation materials <br />will minimize ground water jlows to the mine and ejfectively protect the ground water <br />system adjacent to the mine." It is not cleaz why minimization of ground water flow to the <br />mine would protect ground water gualit~+ adjacent to the mine. This seems more related to <br />ground water uanti .Please review this statement and modify as necessary. <br />17. Other than the statement in Exhibit K on page 20 "the impact of the mine on the regional <br />ground water system is expected to be limited to a very short distance from the mine..." <br />there is a general paucity of analysis or scientific evidence to support the contention of <br />minimal or no impact to ground water users in the permit and adjacent area. The report uses <br />generalizations, simplistic mapping, schematic diagrams and a minimum amount of data <br />from the Ocean Wave coal seams to come to relatively broad conclusions regazding ground <br />water impacts. The report offers no substantive information related to the potential for mine <br />related impacts to registered wells. <br />One useful piece of information in the report is the map (Northfield Mine Registered Wells) <br />showing a minimum of 50 registered wells within one-half mile of the permit azea yet the <br />report completely avoids any meaningful discussion of potential impacts and provides no <br />analysis of drawdown limits and/or estimates, conveys no site-specific hydro-geologic <br />properties, and makes no recommendations regazding monitoring and observation. The <br />report states on page 20 that potential mine inflows have been calculated to range from less <br />than 1 acre-ft per yeaz to 450 acre-ft per yeaz using information and calculations represented <br />in Table 4, one of the few portions of the report that backs up conclusions with supporting <br />information. Assuming those estimates aze meaningful, ground water may flow into the <br />mine at the rate of 0-279 gallons per minute. The Division has researched available data for <br />the registered wells, especially in the southeast portion of the permit and adjacent area. <br />Many of the registered wells used for domestic purposes that are in close proximity to the <br />proposed underground workings have yields of I-3 gallons per minute maximum. <br />Reduction of even a small amount of yield for these wells would be significant to the <br />owners of these wells. <br />Quantification of potential drawdown and impacts to registered wells due to mining impacts <br />is required in order to determine necessary monitoring plans and determine compliance with <br />Rule 2.04.7(3), Alternative Water Supply. <br />~... <br />