2016-06-15_INSPECTION - M1989092 (2)

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PERMIT #: M-1989-092 INSPECTOR’S INITIALS: TOD INSPECTION DATE: March 14, 2016 Page 2 of 6 OBSERVATIONS This normal routine monitoring inspection was conducted by Tyler O’Donnell of the Division of Reclamation, Mining and Safety (Division). Oaklands Ranch (Operator), was represented by David Curtis during the inspection. The Oaklands Ranch pit is located in Douglas County approximately 3 miles south of Sedalia, Colorado. The permit was converted from an 110c permit to a 112c permit in July 2008. The Oaklands Ranch pit is a 25.69- acre 112c Construction Materials Reclamation Permit with a maximum allowed disturbance of 10 acres. The primary commodity being mined at the site is sand and gravel. The 112c Construction Materials Reclamation Permit was issued in October of 1989. The approved post-mining land use is Pastureland. The mine site was surrounded by the following land uses: residential, agricultural, and rangeland. No problems or possible violations were observed during the inspection. During the inspection, the sky was clear and the ground was dry. The site was not active during the inspection; however, it appears that the site sees frequent mining activities. It appears that all mining related disturbance has taken place on top of the Plum Creek terrace or creek bench. It appears that mining started at the crest of the terrace/bench and progressed to the west. There were several pieces of mining equipment and a processing plant located within the northern central portion of the permitted site. There were a lot of; vehicles, scrap metal, construction equipment, and farm equipment scattered around, both the affected land and areas outside of the affected land boundary. The Operator had several other pieces of equipment and parts for mining equipment and processing equipment scattered through the affected lands. At the present time it appears that the mining operation had affected approximately 9 acres throughout the life of mine, with approximately 4 to 5 acres in various phases of reclamation. The Operator was in the process of backfilling and grading the northern and eastern highwalls. It appears that portions of the pit floor have been final graded and vegetation has begun to establish on reclaimed portions of the pit floor. The majority of the area previously affected by the mining operation, has been graded to approximately 2H:1V or flatter. Acid And Toxic Materials: There appeared to be an adequate secondary containment structure around the petroleum storage tank. The secondary containment structure appeared to have enough volume to contain all contents of the fuel tank, plus an additional 10% or more capacity beyond the total capacity of stored petroleum products. Backfilling and Grading: The Operator started mining on a terrace/creek bench located on the west side of Plum Creek, thereby leaving the side slope facing the creek undisturbed. The current pit had been mined down approximately 20 feet, thus leaving the pit floor 10-15 feet higher than the bottom of Plum Creek. Because the Operator started mining the pit to the west of the crest of the Plum Creek terrace/bence and mined to the west, the Operator has left undisturbed land between the pit floor and Plum Creek. The undisturbed land between Plum Creek and the Pit floor essentially looks like and functions as a large sight berm, between the pit floor and Plum Creek. The Division misunderstood the pre-mining topography during the review of TR-02, as a correction the Operator intends to leave the existing, pre-mining topography on the east side of the creek bench/terrace and not mine through the creek bench or terrace. The Operator plans on leaving undisturbed land between the creek and the pit, the Operator is not filling an area to create a berm. There were highwalls around all 3 sides of the current pit excavation, the excavation daylighted to the southeast. The highwalls were approximately 20 feet high and contained a total cumulative length of approximately 775 feet. Portions of the highwalls were vertical, graded to 4H:1V or temporally graded at approximately 2H:1V. No exposed groundwater was observed. At the time of the inspection all slopes appeared to be structurally stable. The western highwall appeared to be graded to 4H:1V or flatter. The Operator was in the process of backfilling and grading the northern and eastern highwalls with imported material. The Operator