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Section II <br />Water Quality Monitoring Plan <br />mean ambient water quality from the subsurface monitoring wells nest samples <br />multiplied by two times the standard deviation of the concentrations. In the event that <br />the water quality at the downgradient wells exceeds the compliance limit, the <br />frequency of sampling at the compliance well will be increased to monthly and the <br />Division will be notified. In the event that ambient water quality is exceeded at any <br />downgradient well for a continuous period of three months or more, potential <br />additional actions will be developed by Denison in consultation with DRMS. <br />The two compliance wells would be installed at the locations specified on Figure 11-1. <br />The wells would be installed in accordance with DRMS and CDPHE requirements, <br />and would be screened within the Salt Wash Member of the Morrison Formation to <br />provide samples of water within the unit affected by Denison mining operations. <br />Plans and specification for the wells would be submitted to DRMS prior to <br />construction and well logs and construction completion diagrams would be <br />submitted after installation. <br />Groundwater sampling would include measuring the static water table with a well <br />probe; purging the well in accordance with best practices; measurement of field <br />parameters including specific conductance, pH, and oxidation reduction potential; <br />and collection of samples for laboratory analyses. The laboratory analyses would <br />include the following: <br />¦ Sampling will include all parameters listed in Table 1 through 4 in CDPHE <br />Regulation 41- Basic Standards for Groundwater for a period of one year with the <br />exception of total coliforms, asbestos, free cyanide, chlorophenol, color, <br />corrositivity, foaming agents, odor, and phenol. <br />¦ After one year of sample data have been collected, the sampling parameter list will <br />be reduced in consultation with DRMS to remove unnecessary analytes. <br />The groundwater monitoring data would be submitted within 30 days of receiving <br />the laboratory data reports and an annual report would be provided to DRMS that <br />compiles the groundwater quality data, evaluates groundwater quality trends, and <br />compares the data to the compliance limit. <br />• <br />11-2 <br />T:164986-Denison MineMTask Order 4 - EPP Sunday Mines GroupTINAL EPPTINAL - Environmental Protection Plan Sunday Mines.doc