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<br /> <br />Westem Fuels proposed and was authorized to modify the groundwater monitoring program to <br />include locations directly up and down gradient of the site. The approved plan consists of existing <br />wells and installation of a new set of wells to monitor the overburden, Dakota Coal and the <br />underburden aquifers (GW-N36, GW-N37 and GW-N38) in the northeast comer of the site, and <br />two alluvial wells (G-N39 and GW-N40) to be located on Calamity Draw upstream and downstream <br />of the mine permit boundary (Map 2.04.7-1). The five new wells were completed in May 1993. The <br />well completion reports can be found in Attachment 2.04.7-2 at the erid of this section. The <br />upstream alluvial well is located in the flood plain neaz Lincoln Street in the south east comer of the <br />mine while the downstream alluvial well is located down gradient of the mine but up gradient of the <br />Nucla waste water lagoons in Calamity Draws. <br />Westem Fuels acquired access to and began monitoring the cluster of wells located in the southwest <br />comer of the project area (wells GW-N16P1, GW-N17P1, and GW-N18P1) in July, 1993. <br />Two other wells, GW-N6 and GW-N22, were investigated for inclusion in the monitoring program. <br />Well GW-N6, located northeast of the permit boundary, was found to be unusable due to the casing <br />being filled with rocks. Well GW-N22, located downgradient of the waste water lagoons on Calamity <br />Draw, cannot be used due to access agreements and may not be appropriate to monitor due to its <br />downstream location from these treatment faalifies. Wells GW-N19, GW-N20 and GW-N21 were <br />also dropped from the monitoring program since they did not serve a practical purpose. <br />All wells are monitored on a monthly basis for water levels. These levels are adjusted to mean sea <br />elevation. Water quality samples will be collected and analyzed for the parameters listed in 2.04.7.2 <br />on asemi-annual basis. Semi-annual samplings will be conducted in February during the non- <br />irrigation season and in August during the irrigation season. <br />Probable Hydrological Consequences <br />A discussion of the probable hydrologic consequences and reclamation plan are contained in Section <br />2.05.6(3) and Section 2.05.6(3)(b)(v) of the permit application document. The following discussion <br />is intended to supplement the description of potential impacts of mining and mitigation of these <br />potential effects. The determination of significance has been made considering the impact on the <br />(Rev. 9/95) 2,04,7_ <br />