2012-12-17_INSPECTION - M1977361

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PERMIT #: M- 1977 -361 INSPECTOR'S INITIALS: MAC INSPECTION DATE: November 30, 2012 OBSERVATIONS The inspection was conducted by Michael Cunningham of the Division of Reclamation, Mining and Safety (Division). Patrick Fischer and Denise Arthur of CEMEX, Inc. were also present for the inspection. The Silica Quarry is located approximately one mile southeast of Lyons, Colorado. The site is permitted for 9.9 acres and the post- mining land use is rangeland. The Division conducted this inspection as part of the normal inspection and enforcement program; the last inspection was conducted on November 18, 2008. The site was not being mined at the time of the inspection; however, the site is considered to be active. According to the 2012 Annual Report, the last date of excavation was on November 1S, 2012. The permit boundary was clearly delineated by monuments and fence lines and the permit sign was posted at the site entrance. The silica stone which is mined at this site is used in the production of cement. A highwall is present along the north and west sides of the pit; the current elevation of the pit floor is the maximum depth to which the pit will be excavated. The Operator has completed interim reclamation on approximately 1.22 acres of the pit floor. The reclaimed area was covered with topsoil and was seeded in an effort to prevent fugitive dust emissions. This area will eventually be backfilled to eliminate the highwalls. Topsoil stockpiles are located at the south end of the site; the stockpiles have been stabilized with jute netting. The highwall on the north end of the pit is approximately 250 feet in length and the highwall on the west side of the pit is approximately 700 feet in length. The northern highwall has nearly reached the north side of the permit boundary; the Operator will not mine any further towards the north. The Division estimates there is approximately 100 feet or less between the western highwall and the west side of the permit boundary. The Reclamation Plan was updated through Technical Revision No. 1, which specified that all highwalls would be reduced to 4H:1V through a combination of drilling /blasting and the importation of overburden material from a nearby permitted mine site. The Reclamation Plan does not specify the volume of material which would need to be imported in order to achieve a final grade of 4H:1V. In addition, the Reclamation Plan does not specify the minimum vertical distance between the highwall and the permit boundary which would be required to conduct drilling and blasting. The Division holds a financial warranty in the amount $223,700.00. Currently the Reclamation Plan does not contain enough detail for the Division to verify if the bond is adequate to complete reclamation; this has been cited as a problem and will require corrective action by the Operator. Please see the first page of this report for additional information. The Division and the Operator discussed alternate Reclamation Plans, including achieving the final grade through benching of the highwall. If the final grade is achieved through benching, the Operator would need to submit a Technical Revision to update the Reclamation Plan. As part of the Technical Revision, the Operator would be required to submit an engineering analysis for the proposed final highwall configuration which would need to meet an adequate factor of safety for long -term stability. Also, the Division may require additional reclamation measures to safeguard the highwall. No other problems were noted during this inspection; the Operator has done an excellent job in maintaining a clean and orderly operation. This concluded the inspection. Pale 2 of 4