2014-12-16_INSPECTION - M1989120

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PERMIT#:M-1989-120 INSPECTOR'S INITIALS: PSH INSPECTION DATE:December 1,2014 OBSERVATIONS The Platte Valley Operation site was inspected by Peter Hays with the Division of Reclamation, Mining and Safety (Division/DRMS) as part of the Division's monitoring inspection program. Mrs. Connie Davis with Aggregate Industries, Inc. was present during the inspection. The site was previously inspected by the Division on May 13, 2010. The Platte Valley Operation 112c permit was issued with conditions by the Division on July 16, 1993. The site is permitted for 190 acres with 133 acres of mining disturbance. The site was actively processing material from the adjacent Wattenberg Lakes site permitted by Aggregate Industries during the inspection. No mining excavation was occurring at the Platte Valley site. As cited as a problem on the first page,the required mine sign was not observed at the entrance gate. The Division will require the Operator to post a sign per Rule 3.1.12(1) and submit photo documentation by the corrective action date.The site boundaries were well defined as required by Rule 3.1.12. The Division currently holds a financial warranty in the amount of$754,732.00. The financial warranty amount includes the costs to backfill the exposed groundwater to comply with the Division's long-term exposed groundwater requirement. The site is covered by a current SWSP for all short-term groundwater impacts. The 2013 SWSP indicated 78.8 acres of exposed ground water at the site. The Platte Valley site is divided into 5 mining phases. Phase 1 has been mined out and is currently used as sediment ponds and process water storage. The conveyor system from the Wattenberg Lake site runs across this phase. The Operator is in the process of regrading and reseeding the sediment pond slopes to promote better long-term vegetation in the phase. The process water pump and conveyor belt system were observed during the inspection. Phase 3 has been mined out and allowed to fill with groundwater to create a groundwater lake. A large overburden pile is located along the northern portion of the east-west oriented lake. Material stockpiles are located along the eastern portion of the north-south oriented lake. Phase 3 was observed from Phase 1 only during the inspection. The Phase 3 slope grading and vegetation was not observed. The approved final reclamation plan for Phase 3 indicates the area will be backfilled to create upland or wetland areas. Phase 5 has not been mined and contains the processing plant, product stockpiles, concrete batch plant and concrete recycling area. The approved reclamation plans states this phase will be backfilled for industrial use. Phases 2 and 4 have been mined to create an open water lake. The eastern portion of Phase 4 is being backfilled by Broda Inert Fill Company to create a future industrial use area. The backfill operation was observed during the inspection. The backfilling is progressing to the south towards the permit boundary. The Operator stated wetland benches have been created in the southern portion and along the southwest shoreline of Phase 2. Due to the high volume of water in the lake and extent of the wetland benches were not visible during the inspection. The Wattenberg Lakes dewatering outlet is located in the northeast corner of Phase 2 and was active during the inspection. The approved mining plans states mining activities will not occur within 100 feet of the Platte River. Based on aerial photograph and field measurements, the current offset from the Platte River to the waterline in the southwest corner of Phase 2 is 70 feet. Mrs. Davis stated the required 100 foot offset was maintained during mining activity; however the Platte River has migrated closer to the Platte Valley site and a large erosion feature has developed on the cut bank adjacent to Phase 2. The Operator's statement was confirmed by Google Earth images of the site. The latest image, dated June 2014, indicates an offset of 70 feet,the October Page 2 of 6