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Probable Hydrologic Consequences of Southfield Mine A. Groundwater Description and Consequences The proposed permit area lies on the southern terminus of the Chandler Syncline, where the Southfield Mine is currently mining the Red Arrow and the Dirty Jack O'Lantern Seams of the Vermejo Formation. Groundwater resources in the permit and adjacent areas are limited in extent due to lenticular lithologies of the potential water-bearing units and because of previous underground coal mine dewatering. Three adjudicated wells were identified within the permit and hydrologically adjacent areas: the Corley Mine Well, the Corley Company Well and the Thompson Well, The Corley Mine Well produces water from mine workings in the Vermejo Formation, The Corley Company Well produces from the Raton Formation, The Thompson Well is within the permit area and was developed in a localized coarse gravel lens on top of a sandstone above the Rex Carbon Seam. The operator has collected baseline groundwater data in the area of the proposed permit area expansion. These wells will serve to monitor both water quality and quantity effects before they extend to the wells to the north. If in the future data suggests that drawdown to the Corley Wells may occur, the operator may be required to install additional monitoring wells closer to the wells of interest and meet the requirements of Rule 4.05.15 pertaining to water rights and replacement. The Corley Company Well is located approximately 800 feet from the proposed permit area boundary, which coincides with the affected area boundary, and its completion zone (in the Raton Formation) is at least 400 feet stratigraphically above the coal seams being mined. Drawdown effects to the Corley Company Well would not be expected at present. The Corley Mine Well is located approximately 1,400 feet from the proposed permit area boundary. This well produces approximately 60 gallons per minute from the abandoned workings of the Corley Mine. EFCI has rights to this water and uses it in mining and processing operations. No significant drawdown effects have resulted from this use and none are anticipated at present. A well permit was issued for the Thompson Well in 1941. Total depth of the well was 338 feet into the Rex Carbon Seam although the source of water is a thin unit above a sandstone at a depth of about 320 feet. Subsequently, the Rex Carbon Underground Mine was developed beneath this area and eventually encountered the well casing. A pipe was connected to the well within the mine workings and water was routed to the surface as a water supply for the Thompson Ranch, At present, the pipe within the mine has been damaged, Also the casing at the surface has been obstructed; both mine and Division personnel have been unable to detect any water level within the casing because of the obstruction. Available information on the well indicates it is at present abandoned, Extensive drilling adjacent to this area by the operator did not reveal any laterally continuous aquifer that could serve as a regional water source. _1P_