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Southfield C1981014: MT6 5 February 19, 2013 <br />Hydrology <br />An extensive review of both the ground water and surface water hydrology can be found in <br />Sections 2.04.7, 2.05.6 and 4.05 of the permit application package. Below is a brief summary <br />of the ground and surface water issues at the Southfield Mine. <br />Ground Water <br />Due to the extensive underground mining activities in the area, ground water baseline <br />information was difficult to obtain. Trends for ground water were established and have been <br />recorded since the mine opened as the Dorchester No.2 in the 1970's. Ground water flow is <br />difficult to predict based on the tendency for the ground water to flood old workings in the <br />area. Many residential wells have been drilled into the old abandoned workings and provide <br />residents with water. In the mine area, evaluation of groundwater resources is based <br />primarily on exploration drilling, records of ground water use, information on regional <br />groundwater characteristics, monitoring information, inflow into underground workings at the <br />Southfield Mine and historic information on abandoned workings. <br />There are three categories of potential groundwater aquifers that occur in the permitted area: <br />1) the Trinidad Sandstone, 2) coals of the Vermejo /Raton Formations and 3) localized river <br />alluvium. A detailed analysis of each of these aquifers is found in the Probable Hydrologic <br />Consequences of the permit application package. All ground water flow into these three <br />aquifers is the direct result of recharge collected from the Wet Mountains to the west. The <br />water flow is structurally controlled by the Chandler Syncline and runs along the axis north to <br />the Arkansas River where it discharges. The Chandler Syncline trends northwesterly. <br />The Conte well is listed as being constructed in Township 70 West, Range 68 West in the <br />Division of Water Resources -State Engineer's Office permit. The location of this well in the <br />permit area needs to be confirmed and updated as necessary. <br />Section 2.04.7 of the PAP discussed potential sources for alternative water supply in the <br />unlikely occurrence that mining operations result in depletion groundwater reservoir. <br />Colorado Division of Water Resources State Engineer's Office (DWR -SEO) requires that all <br />monitoring wells be permitted with their office. EFCI maintains four (4) water monitoring <br />wells: MW -16, MW -23, MW -NW, and MW -65. In accordance with Rule 2.03.10, the permittee <br />shall provide a list of all other licenses and permits needed. All monitoring wells need to have <br />permits with Colorado Division of Water Resources. <br />The Division is currently reviewing water quality concerns, applicable standards, and the <br />approved water monitoring program. <br />Surface Water <br />Surface water in the area flows from the Wet Mountains on the west to the plains on the east <br />then bends northward toward the Arkansas River valley. Most of the streams in the area are <br />ephemeral, flowing in response to snowmelt and intense rainfall events. Much of the <br />