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A1mrG 2004 2003 Annual Hvdrotow ReDOrt ~ Pore 7 3.0 GROUND WATER AND SURFACE WATER MONITORING RESULTS 3.1 GROUND WATER MONITORING RESULTS 3.1.1 Mine Area In the Mine Area, ground water occurs in surficia] alluvial/colluvial deposits and under water table conditions in the sequence of sedimentary rocks corresponding to the Vermejo, Raton, and Poison Creek formations. Due to semi-arid conditions and the limited extent and continuity of the alluvial/colluvial deposits, these units do not store or transmit appreciable quantities of ground water in the general mine area. Variable lithology and significant cross-bedding and inter-bedding within the bedrock geologic units results in limited lateral or regional continuity of potential water-bearing units. As a resuh, there are no known aquifer units and bedrock groundwater occuuences are limited to isolated units and zones that have sufficient local recharge and permeability to store and transmit water. In most cases, this translates into isolated perched ground water occurrences and water storage in abandoned and flooded mine workings, which serve as collection and storage reservoirs for minor ground water and fracture flows (refer to Section 2.04.7 of the Southfield Mining and Acclamation Plan document for more details). In the Mine Area, the current ground water monitoring program includes the following monitoring wells, located as shown on Figures 1 and 2, Mine and Loadout Monitoring Stations: Well Location Death/Completion Completion Zone MW-16 E'/zNW'/. Section 30 136'/106-136' Jack O'Lantem Coal Seam T20S, R69W MW 23 E'/zSW'/< Section 19 179'/149-179' Red Arrow Coal Seam T20S, R69W W'hSW'/. Section 24 1,448'/968-988' Jack O'Lantern Coal Seam MW-65 T20S, R70W MW-NW W'/zSW'/. Section 19 380'/360-380' Red Arrow Coal Seam T20S, R69W Monitoring wells MW-7A, MW-7B, MW-10, and MW-22 were previously included in the monitoring program, but have since been mined-through and eliminated from ongoing motitoring. Well MW-8 was mined-through in 1993 and immediate]}' went dry. Subsequent monitoring showed that the borehole had collapsed to a point 336 feet below the surface. The water level recovered and gradually increased from the 280 foot level beginrilng in early 1996. Measured water levels in this well indicated that sub-surface conditions above the point of collapse had stabilized. In the final quarter of 1999, however, ongoing monitoring indicated that the well had again collapsed at approximately 250 feet below ground surface, making further water level measurements impractical. Field and laboratory analysis data for active monitoring wells are summarized in the following discussions. Raw field and laboratory data for the 2003 water year are provided for reference in Appendices A and B.. Measured water levels for all Mine Area monitoring wells are summarized in Table 4, Monitor Well Water Levels, and historic water level data are graphically depicted for the five monitoring wells (includes historical information for Wells IvNU-8 and IvNV-10) by Figures 3, 4, 5, 6, and 7, Water Levee far lI%I/MlI/-XX Review of historic water level data shows that wells MW-8 and MW-10 caved in late 2000 and have remained dry since. Water levels for well MtV-16 have shown some cyclic r1911%H * 7475 Pme Drone RoaA, .Suite 109 * SteamGaat .SJnru;g CO 80487 * (970J 879-6260 11°:4l'/I :,¢r Pnb nN,mr;,xLi.eMn ipmwn Y{.q pnV nn~..Al1~~m m9m, ~.