Laserfiche WebLink
• Collection and Evaluation of Baseline Data. Dorchester initiated <br /> operations at the Southfield Mine in 1978 shortly after the Surface Mining <br /> Conservation and Recovery Act (SMCRA) became law. At that time, the <br /> current Colorado Regulatory Program had not been promulgated and there was <br /> some question as to requirements and applicability for permitting a new <br /> mine. Given the relatively limited surface disturbance area, and the lack <br /> of site specific hydrologic data, Dorchester worked directly with the <br /> CMLRD and utilized available hydrologic data for the adjacent GEC <br /> operations as well as hydrologic modeling to meet applicable permitting <br /> requirements. In conjunction with review and approval of the Dorchester <br /> permit application, the CMLRD in Stipulations 9 and 10 to the permit, <br /> required initiation of a comprehensive hydrologic monitoring program for <br /> the mine. The baseline program was initiated in 1979 to collect <br /> hydrologic data for both surface and groundwater resources over a period <br /> of approximately one (1) year. Following this initial baseline period, <br /> Dorchester and subsequently EFCI continued hydrologic monitoring <br /> activities, with monitoring intervals reduced to a quarterly monitoring <br />• program from the baseline interval of monthly monitoring. <br />Initial hydrologic information submitted in the original Dorchester permit <br />application included identification of surface drainages and general flow <br />characteristics, modeling of corresponding peak flows and annual runoff <br />volumes, identification of groundwater aquifers and a general description <br />of aquifer characteristics and discussion of groundwater levels, <br />movements, and recharge/storage/discharge characteristics. Subsequent <br />hydrologic monitoring provided additional information and site specific <br />documentation on actual surface flows, surface water quality, groundwater <br />levels, lithologic characteristics, and groundwater quality. Detailed <br />information and discussions on baseline surface and groundwater <br />investigations and results are presented in Section 2.04.7, Hydrology <br />Description of this permit revision application. <br /> Surface Water Occurrence and Use. The Southfield mine area is drained by <br /> several small ephemeral streams including Second Alkali, Newlin, and <br /> Magpie Creeks. It should be noted that Newlin Creek is mapped as a <br />perennial stream, however, upstream diversion of both surface and base <br />flows by the City of Florence result in no consistent base flow such that <br />2.05.6-9 <br />