2009-04-20_ENFORCEMENT - M1983176

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table was being lowered. It is common knowledge among the neighbors that have lived in the area for a long time, that when the Fulton Ditch starts flowing in early March, the groundwater levels start to rise. I have photos and a very accurate description of what has occurred in the past. Unfortunately, some people, including Kirk Kirby, have moved into the area during the time period when "dry" sand and gravel mining was occurring, which lowered the water table in the area. We have direct knowledge that one of the two owners previous to where Kirk Kirby lives, and assume that the other owner, had to constantly pump the basement out with a sump pump in the spring. 5. The fill at the Speer mine site IS NOT an engineered "impermeable" fill for a clay liner and IS NOT keyed into the hard, impermeable bedrock shale for the specific purpose of blocking alluvial groundwater from entering the pit for a water-storage reservoir. The fill was placed on top of 12 in. to 18 in. of sand and gravel that we left on the bottom of the excavation for equipment traction and with the knowledge that the area of fill was not going to become a water-storage reservoir in that location. The fill, and the 2-3 ft. of weathered shale below the fill, will not preclude groundwater from entering the pit and passing through it as it is doing now, to the Platte River. Alluvial groundwater is still entering the mined-out portion of the pit at rates that have been consistent with our operations in the past. Once we de-water a block of virgin sand and gravel with dewatering trenches for draining and to handle the material more efficiently, the transmissivity of the remaining alluvium outside of our excavation slows to its normal rate, as is occurring now. We are not blocking the flow of alluvial groundwater to the Platte and are not slowing it down significantly beyond what were original conditions in what was originally in-place sand and gravel. There is only approximately 800 linear ft. of fill along the eastern edge of our permit area compared to the total 2400 ft. that comprises our eastern permit boundary. 6. There are still questions as to what impact the failed slurry walls of the 120th Ave. Estates Partners former gravel mine (M-2001-185) , up-gradient from Kirk Kirby, is having on the local groundwater conditions. Everyone that we have talked to is in agreement, that the water that is located inside the pit at this site WAS NOT pumped there from another source (usually a major irrigation ditch) as should have been with a functioning sealed reservoir, but is naturally flowing alluvial groundwater that has entered (and is no doubt exiting) through a failed slurry- wall. That water was allowed to fill after the operators shut off the dewatering pumps in the pit in late February 2009. The water that has been backed-up behind the partially impermeable slurry wall is in a much greater volume that what was in the volume of the pit when it was still in-place sand and gravel. Then, logically, there is a build-up of much greater hydrostatic pressure against the down-gradient probably-failed slurry wall, that may be becoming more porous everyday. Is the timing of when this pit was allowed to fill with groundwater and when Kirk Kirby began experiencing elevated alluvial groundwater coincidental or is there perhaps a connection? Has the Division looked into the situation at this pit, in which it appears the DRMS permit holders and operators have left the operation in an un-reclaimed and unstable condition and have "flown the coop"? These are among the major conclusions we have drawn as to why the high alluvial groundwater along that portion of old 120th Ave. cannot be attributed to our partial backfilling of the Speer Mining Resource site. We feel that there are too many other compelling reasons for the return to high alluvial groundwater elevations in the area of