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3-2 23, 1982. Final grading and site clean-up were completed on August 27. Equipment used during slurry wall and pump -back system construction included: o FMC Link -Belt LS -7400 backhoe o CAT-D8K dozer o JD 690-B backhoe o JD 544-B front end loader o Utility/fuel truck o Pumps - B+S 8 hp - Gorman Rupp Co. pump 14C2-F3L - Gorman Rupp Co. pump 16C2-5034 3.2 SLURRY WALL AND EMBANKMENT The slurry wall was constructed in the location shown in Figure 2. The location and length of the slurry wall was chosen in the field to maximize the amount of seepage intercepted. In preparation of the actual excavation, a construction pad was built of compacted fill -along the proposed axis of the slurry wall. This pad was also part of the retention embankment across the valley. The grades along the top of the pad were an average of 2-1/2 percent and all less than 4 percent. Station numbers were instituted along the construction pad to facilitate all measurements. Station numbers began with 0+00 on the west abutment and proceeded eastward extending approximately 430 feet to Station 4+30. (see Figure 2). The bentonite for the wall was mixed into slurry form and stored on-site prior to placement in the trench. Approximately 48.5 tons of premium grade, 124 pounds/barrel yield, Wyoming bentonite were delivered in two truck -loads. lMixing with pond water occurred on the crest of the lower tailings pond. The resultant slurry was pumped to a holding pond just upstream of the proposed slurry wall location. Mixing produced a 1/44 second viscosity bentonite with an approximate specific gravity in the range of 1.06 to 1.08. A 35 -foot reach, FMC Link -Belt backhoe was used for trench excavation. Excavation began from Station 0+00 and proceeded to Station 0+50 on the western portion of the embankment. The drill rig was operating on the eastern " N