2008-03-25_PERMIT FILE - M2008017 (2)

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Subsurface Exploration SCOPE This report presents the results of a subsurface exploration for a proposed sand and gravel pit east of Greeley. The investigation was performed for the owners ~V to identify information that would assist in the installation of a slurry wall. The investigation consisted of drilling 15 test borings, inserting water monitoring wells for each boring and laboratory testing of samples obtained from these borings. Information concerning the monitoring well installation is not included in our scope of work, but was being provided by another consultant. -" The objectives of this study were to (1) evaluate the subsurface conditions at the site relative to the proposed slurry wall construction (2) identify groundwater and (3) identify bedrock depths. The conclusions and recommendations presented in this report are based upon analysis of field and laboratory data. SITE LOCATION AND DESCRIPTION ~~ The site is located north of East 8th Street and east of Balsam Ave in Part of Section 4, Township 5 North, Range 65 West of the Sixth Principal Meridian, Greeley, Colorado. At the time of drilling, the site consisted of native grasses and weeds with an oil battery located east of the west entrance to the site. The main location for the sand and gravel mining had been leveled. SITE EXPLORATION The geotechnical field exploration was conducted October 16-18 and October _ 23-25, 2006 and consisted of drilling 15 test borings. The test borings are shown on the Bore Location Plan enclosed in Appendix A and include visual classifications of each soil, location of subsurface changes, and subsurface water level measurements at the time of this investigation. The locations of the test borings were determined by the client and field surveyed by the client. Table No. 1 provides a summary of the bore locations as provided by the client. The borings were advanced using a 9" exterior/6" interior dual wall percussion hammer drill pipe with continuous sampling done through a cyclone separator mounted on a Drill Systems AP 1000 drilling rig. Samples of the subsoil were obtained to determine an index of the soils with the results listed on the Summary of Test Results noting the depth of specific soils, groundwater levels and bedrock -- locations for each bore. A combination of hammer and reverse circulation drilling were utilized to obtain samples. Samples for use in the laboratory were sealed in the field and preserved at natural moisture content until time of testing.