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<br />• (Page 2) • <br />MINE ID #, OR PROSPECTING ID # M-77-208 <br />INSPECTION DATE 1/20/99 INSPECTOR'S INITIALS CLK <br />OBSERVATIONS <br />The following observations were made during a Operator-requested meeting and inspection of <br />Cement Kiln Dust Storage Areas and reclamation areas at this 112 site. <br />1) Site signs and boundaries were posted as required. <br />2) Further reclamation along the western side of the site has progressed to the point where <br />a partial release of acreage or financial warranty may be possible. Grading and topsoiling <br />have been completed, and revegetation begun. <br />3) A Pit is currently reclaimed, with highwalls in place along the western edge of the pond <br />that were previously approved. Since this is to be a water storage reservoir in the <br />future, this configuration is acceptable as long as public access to the pond is <br />prevented. <br />4) The water present at the bottom of C pit - where the Cement Kiln Dust is scheduled to be <br />stored - is due to surface water runoff and not groundwater infiltration. Interception by <br />most surface water runoff has been prevented by inserting a pipeline into the adjacent <br />ditch, and by grading the surrounding area either level or downhill from the edges of the <br />pit. The water in the pit is constantly recirculated in the dust control system and sent <br />through the water treatment system before being discharged at the NPDES discharge point. <br />Infiltration into the surrounding limestone is believed to be unlikely, but no <br />comprehensive data exists to support this position at this time. <br />The discussion regarding the Cement Kiln Dust disposal began at gam and covered the past and <br />future disposal of CKD at the Lyons Quarry. In the past, approximately 150,000 tons of CKD <br />was generated per year; this has since decreased to 30,000 tons/year, due to operational <br />changes and new mix requirements. The CKD is usually pug-milled with water and then either <br />backfilled into a pit or put into waste piles which are constantly sprayed with water to <br />prevent air transport. When buried in the pits in the past, there has been no direct <br />groundwater interception due to the low water table (averaging 800' below the surface) which <br />does not directly impact the 125' deep pits. After the pits are filled, they are then capped <br />with B-12" of shale and 6-8" of topsoil, reseeded, and returned to pasture use. The permit <br />requires 0-8" of topsoil and 0-10" inches of shale. There has been no elevated pH in the <br />tests for water discharged from the site, and no NPDES violations. <br />Since 1992, DMG has been responsible for assuring that no degradation of groundwater occurs <br />due to operational and reclamation practices at permitted mine sites. Because of these <br />changes, DMG believes it is now appropriate to determine whether future disposal of CKD in <br />the C Pit will have an impact on the surrounding groundwater system. <br />DMG will send a copy of the complaint letter received from the St. Vrain Valley Community <br />Watchdog group to Southdown, as well as copies of TCLP procedures for leach-testing of the <br />CKD, in order to characterize the waste. Zf it is determined at that time that CKD may pose <br />some threat to groundwater quality, further groundwater information, surface water quality <br />data, or information about the water flows, faults, and fractures at the site may be <br />required. The transport mechanisms at the sit, and the likelihood of any contaminants <br />reaching the groundwater may need to be determined. <br />The status of the cement kiln was also discussed, and the possible necessity of bonding for <br />its demolition and disposal. CKD may be regulated under either the Colorado Department of <br />Public Health and the Environment (CDPHE), which would require a Certificate of Designation <br />for disposal of waste that may be considered hazardous. CKD could alternatively be regulated <br />