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Third Perty Oversight 9 Water, Waste & Land, Inc. <br />San Luis Mine June 9, 1994 <br />' 3.0 CONSTRUCTION OVERSIGHT AND QUALITY ASSURANCE TESTING <br />' 3.1 CONSTRUCTION OVERSIGHT <br />Construction field oversight work began on November 11, 1993 and concluded on <br />' December 8, 1993 when the embankment and tailings disposal facility expansion construction <br />was substantially completed. A registered professional engineer from WWL was on site for <br />a majority of each construction day from November 17 through December 8, 1993. On-site <br />observation was scheduled to accommodate the two-shift per day construction schedule. The <br />engineer generally observed and reviewed all phases of construction activities undertaken both <br />by BMRI and subcontractors including: <br />' ^ Construction techniques and material placement methods, <br /> <br /> <br /> <br /> <br /> <br />t <br /> <br />1 <br />1 <br /> <br /> <br /> <br />^ Borrow area excavations and general material types, <br />^ QA sampling and testing including VLDPE welding, vacuum and destiructive tests, <br />and fill material density, gradation and permeability tests, <br />^ Shift changes between the day and night crews to verify continuity of material <br />selection from the borrow areas and placement methods by the operators, <br />^ QA test results conducted both on-sight and off-sight, and <br />^ Technical submittals. <br />Daily field logs were completed by the engineer. Copies of the logs are located in <br />Appendix A. <br />Several occasions arose during construction when materials or construction techniques <br />being employed may have created some concern with the DMG. Examples inolude isolated <br />areas where drain spacing was greater than the specified 40 feet and isolated truckloads of <br />embankment fill containing significant quantities of oversized materials. Asthese occurrences <br />were infrequent, the engineer decided not to immediately contact the DMG, but did note any <br />potential problems in the daily field logs and in the weekly reports to the DING, and also <br />brought the materials/techniques to the attention of the field QA personnel in a timely matter. <br />This allowed on-site QA personnel to verify materials/techniques before additional construction <br />activities covered the areas in question. <br />3.2 QUALITY ASSURANCE TESTING <br />In general, QA test results provided appear to be adequate and valid. 'T'his includes <br />results from tests conducted before and after third-party oversight. Table 3.1 provides a <br />summary of the frequency of QA tests conducted on construction materials based on the Final <br />Construction Report ISRK, 1994). <br /> <br />