1997-09-15_REVISION - M1981302 (8)

Home Browse Search

November 21, 1997 Flatiron Companies P.O. Box 229 Boulder, Colorado 80306 RECEIVED Attention: Mr. Ed McDowell NOV 2 6 tr197 Subject: Observation/Dressing of pivfeRif+of Minoralo A Ggplgqy Levee at Deepe Farm Pit Boulder, Colorado Job No. 25,385 Gentlemen: Mining of the Deepe Farm Pit has been stopped and the pit is being reclaimed. Part of the reclamation plan is the dressing of the existing levee bordering the south and east sides of the mining area. This report summarizes the results of our observation of the earthwork done to dress the levee to design slopes and grades (construction drawings prepared by Ayres Associates, Boulder, Colorado and titled "Levee Embankment Earthwork, Deepe Pit, South Boulder Creek, Boulder, Colorado" and dated October 3, 1997). As requested, on October 6, 1997, we investigated the soils in the proposed borrow area. The locations of the test pits are on Figs. 1 and 2 and the summary logs are on Fig. 3. We advised the contractor the soils exposed by the test pits were acceptable for compacted fill to dress the Deepe Farm Pit levee. The earthwork was started October 9, 1997 and was completed October 16, 1997. The contractor used 1 Caterpillar 815 sheepsfoot roller, 1 water truck, 2 Caterpillar 627B scrapers and 1 Caterpillar 140G grader to place the compacted fill required to dress the levee. The soils for dressing the levee were borrowed from the areas in which the test pits (See Figs. 1 and 2) were excavated. The areas to receive fill were stripped of vegetation, prepared and compacted according to specified requirements. The levee fill soils were gravelly, clayey sands and sandy, clayey gravels with a maximum 6-inch size. These soils were hauled to the levee, spread in approximately 8-inch loose lifts, moisture conditioned to near or just over optimum moisture content (see attached Table I for compaction test results) and compacted. The soils were compacted with the roller to densities in excess of that needed to meet the required percent compaction of 95 percent (ASTM D 698). In our opinion, the fill placed to dress the Deepe Farm Pit Levee meets the specification requirements. CTUTHOMPSON, INC. CONSULTING ENGINEERS 1971 WEST 12TH AVENUE • DENVER.COLORADO 80204 • (303)825-0777