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-- (Page 2) MINE ID ~ OR PROSPECTING ID #` M-77-081 INSPECTION DATE 5 13 94 INSPECTOR'S INITIALS GSC This was a partial inspection conducted in response to a citizen complaint by Mr. Elmer Andrews of 2434 C Street NW in Greeley. He contacted Water Division One about potential well injury from gravel operations conducting dewatering activities in the vicinity. These concerns were presented to the Division of Minerals and Geology (Division) by Mr. Shawn Hoff, Water Commissioner for Division One, District Three in a letter received on Hay 2, 1994. The letter stated that Mr. Andrews wished to redrill well W-5122 but had concluded that the alluvial aquifer ie completely drained. The purpose of the inspection was to determine if pumping and dewatering activities in the nearby mine operations could be impacting Mr. Andrews' wells which were decreed in 1973 and 1974. The Division's current understanding ie summarized ae follows: Mr. Andrews' Wells: Andrews Well No. 1 (Decreed in W-5122) Total Depth = 48' below ground level (bgl), redrilled about 10 years ago, drilled about 3 feet into shale underlying gravel (according to Mr. Andrews), submersible pump suspended in 6" PVC casing; pump level unknown. Wolf Well No. 2 (Decreed in W-2710) Total depth =21' bgl, 6" PVC casing, drilled approximately in 1958, pumped in past with a 3 HP Monarch type A pump located on the surface at approximately 40 gpm. Wolf Well No. 2 is not being used at this time. These wells are situated in the unconfined alluvial aquifer which is being dewatered by the nearby sand and gravel pits. The wells and the pits are located in a broad alluvial plain with little variation in the ground elevation. Mr. Andrews uses his wells for livestock water and lawn and pasture irrigation on approximately 7 acres. He stated that historic static water levels (SWL) ranged from 6 to 12 feet bgl in each well in the past 15 years. The average static level has been about 9' bgl in the past 3 to 4 years. Mr. Andrews has not kept written water level records for his well and these levels are estimated. He also stated that after pumping for about half an hour, the production in the deeper well decreases and sand and grit fouls up the irrigation system. The collar elevations for both wells are approximately the same. The static water levels were measured with the Division's water level indicator during this inspection and the results are noted as follows: W-5122 - Andrews Well SWL = 17.50' bgl w-2710 - Wolf well SWL = 16.75' bgl This represents an apparent drop in the static water level of approximately 8 feet. Greeley West Pit The Greeley Weet Permit ie located approximately 1500 feet northwest of Mr. Andrews' wells. The operation was inspected with Mr. Hoff and Mr. Andrews. The operator representative, Mr. Greg Lindsay, was also present during this inspection and answered questions about the operation. This is a phased 112 operation with 3 pits having been completed and allowed to fill with water. Pit D currently is being mined and dewatered. The pump ie located about 2,300 feet northwest of Mr. Andrews' wells. The pump, rated at 3,100 gpm, was operating during the inspection. The depth to the water level was estimated to be 25 feet bgl at the pump location near the northeastern end of the pit. The measurement was made with a clinometer. In a dewatering trench located on the south end of the pit, the water level was estimated at about 15 feet bgl. It should be noted that the Division is not aware of any monitoring well system associated with the Greeley Pit which could be used to provide supporting or contradictory data related to injury claims. Mr. Lindsay believed that the previous operator of the Greeley Pit (Flatiron Sand 6 Gravel) had been involved in litigation with local well owners prior to 1987. He said he thought the issue was resolved upon determining that the drop in water levels in those wells was attributed to decreased aquifer recharge resulting when farming irrigation ceased in the area. Mr. Lindsay pointed out that the land now being mined previously was irrigated farm land.