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i t • • 0 o v ~ v 0 0 For: J. A. Kilter June 14, 1993 SECTION 16 FILL CONSTRUCTION UPDATE AND CERTIFICATION On June 10, 1993 I accompanied Mr. James A. Kiger, Colowyo's reclamation supervisor, on an inspection of the Section 16 Fill. The purpose of this visit was to observe the condition of the fill and to satisfy the requirements of CDMG Rule 4.09.1(11). No significant construction activity had occurred to date this year. During the inspection, we observed some drainage problems related to a severe rain storm that occurred on May 16. This storm was obviously far in excess of the design for the surface drainage structures. Below the 7725 bench, erosional cuts 6-12" in depth on the bare spoil slopes were observed. Some of the rip-rap in the as yet unfinished Section 16 Fill ditch had been washed out and the water had channelled around some of the larger boulders in the rip- rap. The bare spoil slopes above the 7725 bench exhibited erosion but to a lesser degree. The unfinished Section 16 Fill ditch above the 7725 bench appeared to be in good condition. A small seep was noted on the extreme east end of the fill. There does not appear to be a ground water source for this seep and Mr. Kilter indicated that some mud and snow had collected near the seep location during construction and mining in the adjacent dragline pit. If this is the cause for the seep, it should dry out. This will be confirmed in future inspections. In any event, this seep is not expected to cause any problems as it is in an area of thin fill with very little material above or below it. I also interviewed Mr. Ed Moyer who personally supervised the construction of the Section 16 Fill under my direction. Mr. Moyer confirmed that he didn't know of any ground water source for the observed seep. Mr. Kiger indicated that during the spring runoff the underdrain at the tce of the fill flowed water in excess of 50 gpm. The source of this water was surface runoff water entering the head of the underdrain above the fill. The underdrain appeared to stop flowing concurrent with the end of springtime surface runoff. At the time of my inspection there was no flow of water from the underdrain. The fill exhibited no appearances of instability, structural weakness, or other hazardous conditions.