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(Page 2) MINE ID # OR PROSPECTING ID # M-1977-208 INSPECTION DATE 03/20/07 INSPECTOR'S INITIALS ESC OHSSRVATION3 This was an inspection of the Lyons Quarry conducted by Erica Crosby, Carl Mount and David Bird of the Division of Reclamation, Mining and Safety. Monica Sowdera, Pat Fisher and Stephano Demartin of CEMEX, inc. and Alan Notary of Brown and Caldwell were present during the inspection. The purpose of the inspection was to monitor the backfilling of the C-Pit and discuss the new piezometers and monitoring wells proposed on site. The Division met with CEMEX personnel and their consultant to discuss a new monitoring plan that was requested by the Division to address water quality and monitoring of C-Pit water. CEMEX has recently installed an automatic level recorder in the C-Pit and the existing monitoring well CEM-001 to measure water elevation (head), pH, dissolved oxygen, oxygen reduction potential and conductivity. The intent is to determine the recharge rate and fluctuation from the waters in the C-Pit and the existing well completed in the Fort Hayes Formation (CEM-001). According to the operator, it takes approximately 68 hours for well CEM-001 to recharge. To determine the source(s) of water in the C-Pit and to accumulate additional water data, CEMEX proposes 5 additional piezometers and 3 additional monitoring wells in proximity to the pit. The piezometers will be installed around the western end of the C-Pit and the monitoring wells will be installed on the eastern end of the pit. Two of the monitoring wells will be completed into the shale unit and a final monitoring well will be installed into the alluvium. Surface water gauging locations are also proposed on the Boulder Feeder Canal and the Swede Ditch to determine if the ditches are leaking water and migrating into the C-Pit. A copy of the proposed map noting the location of the sites is attached. The operator intends on filing such changes in the form of a revision to the permit. The Division observed material being hauled in from existing stockpiles on site to backfill portions of the C-Pit. Approximately 7-e scrapers were noted dumping material on the northwest portion of the pit. Two dozers were pushing the material into C-Pit. Patches of cement kiln dust {CKD) were noted in C-Pit and possibly exposed to wind erosion. CEMEX will need to ensure that the CKD is covered during the backfilling project and not be subject to wind erosion. The Division observed the stockpile/borrow source actively being used to backfill the C- Pit. The material is mainly historic waste rock consisting of shale. The size of the material varies from 5" minus to small boulders. I & 8 Contact Address NAME Ms. Monica Sowders OPERATOR STREET CEMEX, Inc. 5134 Ute Hwv CITY/STATE/ZIP Lyons, CO 80504 ^ CE ^ BL ^ FS ^ HW ^ HMWMD (CH) ^ SE ^ WQCD (CH) Cc: Carl Mount; DRMS David Bird; DRMS