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originally suggested including thallium in the water analysis. In order to remove thallium <br />from future water sampling analysis, the Division requires more substantial justification that <br />thallium levels would no longer be of concern at the site. <br />4. Under the Monitoring and Compliance Points, the Proposed Sampling and Analysis Plan <br />Lyons Quarry states, "CEMEX proposes to install two wells to serve as monitoring and <br />compliance points. The first well designated as the monitoring point (Well 1) will be located <br />midway between A and C Pits along the hydraulic gradient. The second well designated as <br />the compliance point (We112) will be located downgradient from A-Pit as near as feasible to <br />the CEMEX property boundary. Both wells will be drilled and screened to collect <br />groundwater from the Fort Hays Limestone member." Further, under the Well Sampling <br />Protocol, the Proposed Sampling and Analysis Plan Lyoris Quarry states, "Samples for <br />laboratory analysis will be collected only after a minimum of three water-column volumes <br />have been purged. If water is not present in the well following purging, then the sampler <br />shall wait 7 days and attempt to resample. If there is insufficient water in the well after the <br />third attempt, the well shall be deemed dry for that sampling period." The Division believes <br />that placement of the monitoring and compliance wells into the Fort Hays Limestone member <br />is not the most effective approach to monitoring the groundwater at the site. Unless there are <br />any agricultural or residential wells downgradient of C-Pit that tap into the Fort Hays <br />Limestone, it appears that contamination of groundwater in that member would have no <br />impact on groundwater users. Of greater concern to the Division is the aquifer tapped by <br />users in the area, which, to the knowledge of the Division, is the Dakota Formation. <br />Additionally, the Division believes that there is a good likelihood that, according to the <br />above sampling protocol, the wells may yield few if any samples due to the tightness of the <br />Fort Hays Limestone member. The Division does not accept a "dry well" result in place of a <br />sample for a monitoring or compliance well. Therefore, in the interest of monitoring the <br />aquifer used in the area and acquiring samples to be analyzed, the Division believes that the <br />monitoring and compliance wells should be drilled and screened into the Dakota Formation. <br />If, in fact, there are users in the area that tap into the Fort Hays Limestone member, the <br />Division may reconsider this position. <br />5. Under the Monitoring and Compliance Points, the Proposed Sampling and Analysis Plan <br />Lyons Quarry states, "Both wells will be sampled quarterly. If four consecutive quarters <br />yield results below the MCL, then sampling frequency will be reduced to annual." The <br />Division does not agree to this predetermined trigger to reduce sampling frequency. The <br />Division believes that the quarterly sampling should continue indefinitely. If, at some point <br />in the future, the Operator desires to reduce sampling frequency, the Operator should submit <br />a Technical Revision request indicating the change in sampling frequency. At that time the <br />Division will review prior sampling results and determine whether reduced sampling <br />frequency is appropriate. <br />6. Under A and C Pits, the Proposed Sampling and Analysis Plan Lyons Quarry states, "A and <br />C Pits will continue to be sampled biweekly until the installation of Well 1. Following the <br />installation of Well 1, both pits will be sampled quarterly. If four consecutive quarters yield <br />results below the MCL, then sampling frequency will be reduced to annual. If annual samples <br />yield results above MCL, quarterly sampling will resume. Sampling will be discontinued in <br />A Pit once 4 consecutive annual samples yield results below MCL." The Division agrees that <br />once the monitoring well (Well 1) is installed, sampling of A Pit maybe reduced to quarterly <br />sampling. The Division does not agree, however, that the frequency of quarterly sampling in <br />A-Pit can be reduced prior to the reduction of pH and selenium levels in C-Pit water. Once <br />the acceptable levels are reached in C-Pit water, if the Operator desires to reduce sampling <br />