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(4) <br />_ the base of excavation contours and the extent of colluvium fill in the base <br />• and both ends. The colluvium cover over the coal waste is shown on diagram ~2. <br />The select material used was a 3" crushed gravel. Attached is lab <br />test results required and done by RAIG. Fill with select material started <br />Nov. 10 1984. Pumping was done in the base between the excavation and fill <br />and during fill. Minus 8" pit run was used in the first Eoot of Eill to <br />establish a more stable contact with the base of excavation. RMG's recommen- <br />dation in their Nov. 9 inspection report to slope the contact of colluvium <br />and select material was not followed because it was not received until the Eill <br />was near completion. I~istead, a near vertical contact was made near 21~R00. Both <br />methods were discussed as acceptable in initial discussion of the subject 11-6-84. <br />The underdrains were started 11-14-84. The lateral drains were dug <br />approximately 5'-3' wide anJ with vertical sides. The main drains were dug <br />• 3-5' deep and 3' wide. The trenches were lined with Supack 4 NP drainage <br />fabric and filled with gravel.. The gravel being used is 3,'4" wash gravel. <br />Western Colorado Testing did a sieve analysis of the gravel and ItMG approved <br />of the material.Diagram 3 shows the location of the drains as installed and <br />spot elevations. Discussions with IUIC indicated that the placement of these <br />drains according to design location was not critical and that the base of <br />the excavation would affect t}~eir locationthe most. The affect of the base <br />o~ excavation can be seen in the north end oC the second lateral up from <br />the bottom. Tlie installation of these drains is an on going project. Due <br />to the sCeep slope that the drains are installed in, only 10-15' of vertical <br />installation o~ the main draius ain be done at one time. The bottom of. <br />these drains has not been daylighted due to the lack of completion of <br />the rock toe; therefore, their ei~ectiveness has not been observed yet. <br />• <br />