Laserfiche WebLink
Laboratory analysis: <br />The wells are sampled in a sequence that follows the order of least to greatest level <br />of salinity. At the end of 2016 this sequence continued to be: (1) FPW, (2) AMW-1, <br />(3) DH -96, (4) DH -122, (5) SMW-2 and (6) AMW-2. Ash Monitor Well No. 2 <br />(AMW-2) still continues to recharge following the conclusion of the A -Pit <br />reclamation activity. This process has been ongoing since the end of 1999 when A - <br />Pit reclamation was completed, but only since 2004 has it resulted in volumes <br />sufficient to allow sampling. Adequate water volumes were found in this well <br />during each of the samplings for 2016, making it possible to obtain samples <br />following the standard three -well volume purge procedure. While the well bore <br />water level recovery following testing remains slower, higher static water levels <br />provide evidence that the highly disturbed zone in the reclaimed overburden area is <br />recharging. The timeline for this recharge is consistent with previous predictions. <br />Copies of the analytical laboratory test results are found in the pages following this <br />text. Each ground water monitoring well was sampled in accordance with the <br />"permit procedure". The `B" designation following the well identification confirms <br />that the laboratory sample was obtained after initial field sampling, well purging and <br />a subsequent (second) field sampling. The 2016 ground water monitoring test <br />results remain consistent with results from previous year's analyses in that there <br />have been no confirmed statistical exceedences, with but one exception, the samples <br />obtained from the SMW-2 well during 2004. The SMW-2 well is completed in the <br />disturbed spoil material which is being subjected to slow re -saturation by ground <br />water, and appears to be leaching dissolved minerals as the water table rises. This <br />has caused manganese concentrations to somewhat exceed the calculated tolerance <br />limit. CEC addressed this tolerance limit exceedence with CDPHE during 2005, <br />and was granted permission to continue the current detection monitoring program <br />[Doty & Associates letter dated 04/08/05, "Alternate Source Demonstration, <br />Statistically Significant Increase Over Background Manganese in SMW-2, Fourth <br />Quarter 2004, Keenesburg Disposal Facility"]. <br />The direction of ground water flow, to the extent that it has been documented in the <br />area of the Keenesburg Mine property, trends downgradient to the northeast. <br />Recharge of the aquifer in the "spoil area" continues to be limited to a single source, <br />the localized infiltration of precipitation to the subsurface. There is no evidence of <br />any significant ground water recharge to the site from the Ennis Draw fluvial <br />ground water system. Ground water elevations in the sampled Ennis Draw wells <br />close to the Keenesburg Mine site are significantly higher than in either the spoil <br />monitoring well (SMW-2) or in the ash monitoring wells (AMW-1 or AMW-2). <br />59 <br />