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M~N7GOMERY WATS~N <br />Miilirlg Gttisup <br /> <br />Date: June 20, 2001 <br />To: Seneca Coal <br />From: Tom Leidich <br />Subject: Haul Road D Construction Quality Assurance <br />The purpose of this memorandum is to present the results of quality assurance testing performed during the <br />construction of Haul Road D. The aligtunent and stationing of the haul road aze shown on Drawing 1. <br />Four representative material samples (Sandy Clay, Very Sandy Clay, Silty Sand, and Sandstone) were collected <br />and standazd Proctor tests (ASTM D698) were conducted to assist in the QA/QC procedures to assure [hat <br />the placement of fill meets the design and engineering compaction spedfications for the approved designs in <br />the PAP. Seneca and Montgomery Wa[son personnel collected the samples and Northwest Colorado <br />Consultants conducted the testing. These tests resulted in maximum dry densities ranging from 103 pcf <br />(sandstone) to 111.4 pcf (very sandy clay). The more conservative density of 111 pcf was selected as'the <br />• target level for density testing during the construction of all haul roads and pond embankments in the II-W <br />and Yoast Mine areas. The results of the Proctor tests aze included in Attachment A, Moisture-Density <br />Relationship. <br />Haul Road D <br />Seneca began constructing Haul Road D in eazly August The construction from Stations 7+00 to 40+00 is <br />completed however, road-surfacing placement is ongoing at this time. The following is a chronology of <br />testing events and results of the testing conducted. A summary of the field density testing resulu is <br />presented in Table 1, Yoast Mine -Summary of Testing. <br />8/11/99 -Montgomery Watson personnel observed the cut and fill techniques being implemented between <br />Stations 7+00 and 22+00. The majority of the road is a cut/fill balance with about five feet of fill being <br />placed on the downhill section- All fill operations appear to meet the placement speafications. <br />8/16/99 -Four nucleaz moisture/density tests were conducted using a Troxler Gauge. The tests were taken <br />at Stations 7+00, 10+50, 15+50, and 21+00 on final elevation of the subgrade. All test results were within <br />90% of the maximum dry density value of 111 pcf <br />8/25/99 -Four nucleaz moisture/density tests were conducted using a Troxler Gauge. The tests were taken <br />at approximate Stations 28+OQ, 31+00, 35+OQ and 40+00 on final elevation of the subgrade. All test results <br />were within 90% of the maximum dry density value of 111 pcf. <br />• <br />J:~970108 Seneca C°aAWOrQJ/aulmad D Quality ASfulanCe Mrnm.dx <br />