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Groimdwatier Monitoring -New Horizon 2 Mine • V~kstem Fuels proposed and was authorized to modify the groundwater monitoring program to include locations directly up and down gradient of the site. The approved plan consists of existing wells and installation of a new set of wells to monitor the overburden, Dakota Coal and the underburden aquifers (GW-N36, GV~N37 and GV~N38) in the northeast comer of the site, and two alluvial wells (G-N39 and GV~FN40) to be located on Calamity Draw upstream and downstream of the mine permit boundary (Map 2.04.7-1). The five new wells were completed in May 1993. The well completion reports can be found in Attachment 2.04.7-2 at the end of this section. The upstream alluvial well is located in the flood plain near Lincoln Street in the south east comer of the mine while the downstream alluvial well is located down gradient of the mine but up gradient of the Nucla waste water lagoons in Calamity Draws. Western Fuels acquired access to and began monitoring the duster of wells located in the southwest comer of the project area (wells GW-N16P1, GV~N17P1, and Gl/1FN18P1) in July, 1993.. The two sets of wells, G1/~N36, GW-N37 and G1/~N38 in the northeast comer of the permit area, and GW-N16PI, Gl/~N17PI and G~A,rN18Pl in the southwest comer of the permit area v~ill adequately monitor groundv~rater flow activity covering the Garvey/Butbridge leases. Two other wells, Gl/~N6 and GW-N22, were investigated for inclusion in the monitoring program. Well GV~N6, located northeast of the permit boundary, was found to be unusable due to the casing being filled with rocks. Well GV~N22, located downgradient of the waste water lagoons on Calamity Draw, cannot be used due to access agreements and may not be appropriate to monitor due to its downstream location from these treatment facilities. Wells GV~N19, GV~N20 and GV~N21 were also dropped from the monitoring program since they did not serve a practical purpose. All wells are monitored on a monthly basis for water levels. These levels are adjusted to mean sea elevation. Water quality samples will be collected and analyzed for the parameters listed in 2.04.7.2 on asemi-annual basis. Semi-annual samplings will be conducted in February during the non- irrigation season and in August during the irrigation season. PROt3/1BLE HYDROLOGICAL CONSEQUENCES (Revised ¢s9s~ 2.04.7112 • _~_,..