2009-04-08_INSPECTION - M1983176

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(Page 2) MINE ID # OR PROSPECTING ID #: M-1919 3-1 76 INSPECTION DATE: INSPECTOR'S INITIALS: DR? OBSERVATIONS The Division responded to a written complaint from a citizen, Mr. Kirk Kirby, who resides at 10221 East 120`h Avenue, Henderson, Colorado, approximately 300 ft southeast of the Speer Resources mine site operated by Asphalt Specialties Co., Inc. (Operator). Mr. Kirby indicated that his basement started flooding on Friday, March 20, and that he was pumping about 250 gpm from his basement sump and wells on his property to keep his basement dry. Mr. Kirby also stated he had observed that the mine had started pit backfilling activities in recent months, and he blames the Operator for the water problem due to the introduction into the pit of backfill material with lower permeability than the surrounding material, with a consequent ground water mounding effect on the upgradient side of the pit. David Bird and Tony Waldron met Mr. Rob Laird, Land Manager for the Operator, at the mine and discussed the issue. Mr. Laird stated that pit backfilling had started in January 2008, and that the backfill material was overburden from a different pit. Therefore, Mr. Laird agreed with the Division that the backfill material could have different permeability and transmissivity than the in situ material upgradient of the pit. Mr. Laird provided maps and water level measurement data from two monitoring wells, MW3-AS and MW9-AS, located at the eastern boundary of the permit area and believed to be hydrologically upgradient of the pit. Charts depicting the data since June 2004 are attached to this report. The attached charts show anomalous rises in the water level of both wells in the months following the start of backfilling. Well MW9-AS rose 2Y2 feet in February 2008, and has continued to rise since. Well MW3-AS rose 4.8 feet from June to August 2008 and also has continued to rise since. A monitoring well (Well B-MW4) owned by the South Adams County Water and Sanitation District located on 120`" Avenue between the Operator's pit and Mr. Kirby's property also showed a recent rise in water level and on March 19, 2009 was at a level of 4.25 ft below ground surface, which is the highest recorded water level since measurements started in 1990. Mr. Laird brought to the inspectors' attention that the 124th Estates Gravel Pit (M-2001-085; operated by 124th Estate Partners), located approximately 1,000 feet northwest of Mr. Kirby's property, had recently started filling with water. It is also worth mentioning that 124th Estates Partners had reported to the Division in September 2008 that the slurry wall around the pit was compromised in two locations and the operator was in the process of repairing the wall. On March 30, Harry Ranney, Eric Scott, and David Bird of the Division returned to the site and surveyed elevations in the area. The survey indicated that the elevation of the 124th Estates Gravel Pit lake is 2.2 feet lower than the elevation of the bottom of Mr. Kirby's basement. The Division therefore concludes that the 124`h Estates Gravel Pit Lake is not a source of water entering Mr. Kirby's basement. Two additional potential sources of water were investigated. First, the possibility that other mining in the vicinity could be responsible for rising ground water levels was discounted for the reason that no active mining is occurring in the immediate area. With the exception of the 124th Estates Gravel Pit, former mines immediately surrounding Mr. Kirby's property have been decommissioned for many years. Second, leakage from the Fulton Ditch was considered as a possible source. The ditch has been flowing at variable rates during the current water year (see attached hydrographs), but the current discharge rate is less than in the past when no impacts were reported.