Laserfiche WebLink
ccc'2� <br /> CIVIL RES"tURCES <br /> Four (4) of the piezometers showed a rise greater than three (3) feet above the seasonal baseline in May 2015 after <br /> which the wells dropped back to baseline levels. The wells that saw a rise in May 2015 are: MW-3, MW-7, MW-9, and <br /> MW-10. All of these wells are along the river/east side of the Site (See Figure 1). The rise in groundwater elevations <br /> corresponds to a higher than average South Platte River discharge that was observed during May and June of 2015. As <br /> shown from the South Platte River at Fort Lupton (PLALUPCO) station graph in Attachment A, the river discharge during <br /> this monitoring period was approximately six (6) times the discharge measured during the baseline measurement period <br /> in 2004. <br /> Two (2) of the piezometers (MW-3 and MW-7) were slightly above the three (3) foot seasonal rise compared to baseline <br /> from September through December of 2017. The construction of BURNCO's Lupton Meadows slurry wall was <br /> completed in July 2017. MW-3 is directly south of the Lupton Meadows slurry wall and MW-7 is directly north of the <br /> slurry wall. After the construction of the slurry wall, both wells did not drop in the fall according to their seasonal pattern. <br /> It is likely the slurry wall disrupted this drop causing elevated water levels for a couple of months. After the slurry wall <br /> had been in place for a season MW-3, which is upgradient, continued to have higher groundwater elevations than were <br /> observed in the previous years. On the other hand MW-4, which is downgradient, saw lower observed groundwater <br /> elevation after the slurry wall had been in place for a season. Due to these observed trends, the Lupton Meadows slurry <br /> wall is likely to be the determining factor in the observed change in groundwater elevations past the summer of 2017 in <br /> MW-3 and MW-7. <br /> Conclusions: <br /> The Heit Pit slurry wall has been in place since June 2007 and groundwater elevation measurements have been taken <br /> continuously since September 2013. In comparing these values to the baseline groundwater elevations observed prior <br /> to slurry wall construction it has been demonstrated that the Heit Pit slurry wall had minimal effect on the surrounding <br /> groundwater table and are within the allowable range determined by the MLRB. The remaining mining and reclamation <br /> activities will all take place within the approved slurry wall and will not change the current hydrologic balance in the area. <br /> Therefore, CCOB requests that the DRMS groundwater monitoring requirement be removed from this point forward. <br /> Sincerely, <br /> CIVIL RESOURCES, LLC. <br /> Kyle Regan, P.G. <br /> Cc: Brennan Middleton (Via Email) <br /> Attachments: <br /> Figure 1—Piezometer Map <br /> Pictures of Destroyed Wells <br /> Attachment A— Graphs <br /> Attachment B—MLRB Decision <br /> Attachment C— Water Elevation Tables <br /> JA8roomfie1d-329\DRMS\TR-5 Water Levels\TR05 Letter-DRAFT.doc <br />