Laserfiche WebLink
The water levels in the three GE wells stabilized in 1990, which is thought to be due to <br />the length of time since dewatering stopped at the adjacent underground operation. <br />Water levels in the bacld"ill areas are depressed and are not likely to ever recover t~o pre- <br />mine levels. Map 2-1 shows that the levels in the backfiil and downgradient aquifers are similaz. <br />Well pairs GD3-GD2 and GF11-GF6 present water levels that are very similar in water-level <br />elevation for the backfill and downgradient QR aquifer well. Mining is significantly increasing the <br />permeability ofthe mined aquifers which is a benefit relative to potential yields from the aquifer. <br />The increased permeability will likely not allow water levels to recover to pre-mine levels in the <br />reclaimed pits except neaz the northern (down-dip) end of the mined area, where levels will be <br />above their pre-mine level. Water levels in the native aquifer downgradient ofthe mining will likely <br />stabilize above their pre-mine levels. <br />Significant drawdown has developed adjacent to the pits but the extents of these • <br />drawdowns is very limited due to the small transmissivity in these aquifers. Recovery ofthe water <br />levels has occurred over a few years as the pits have moved away from an area. <br />Variations in natural rechazge to the 2nd White Sandstone affects this aquifer greatly. <br />Mining affects on the system has not been detected. <br />The conductivity of water in backfill wells GD3, GFS, and GFl l are somewhat higher but <br />similar to those of the native aquifers in these areas. Conductivity for GFS is approximately 1.5 <br />times the pre-mine value. Conductivity for backfill well GF7 is much higher than the naturally <br />observed concentrations and will probably be higher for several years before returning to pre-mine <br />concentrations. Major constituent concentration in water in this well may be starting to gradually <br />decline. The water quality in QR wells GD2 and GF6 has been only slightly affected by the • <br />Tf_ -66 <br />6-2 (Revised 09/21/95) <br />