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• both shoulders. A majority of the ditchlines appeaz to be removing the surface runoff away from the <br />roadways adequately; however, we did observe a number of azeas where the ditches were not adequately <br />removing the runoff away from the roadway sections. <br />Field Investigation: The field investigation for this project was conducted on November 3, 1999. Six <br />(6) shallow test holes were advanced along the West Refuse Pile Haul Road and the Haul Road B <br />Extension to explore the existing pavement and subgrade conditions, and to obtain saznples for laboratory <br />testing. The test holes were excavated with a rubber lire backhoe provided by the client. The test holes <br />were advanced to depths ranging from 2 to 3 feet. The test holes were logged by a representative of <br />NWCC, Inc. Graphic logs of We test holes were not drawn; however, a table indicating the location, <br />road base and subbase gravel thicknesses and subgrade soil types encountered in each hole are presented <br />later in the Subsurface Conditions section of this report. The pavement section and subsurface conditions <br />along the Fish Creek Borehole Access Road were not investigated at this time. Our firm previously <br />investigated this access road and provided recommendations for improving it in a report prepared under <br />our job number 95-2431 and dated October 9, 1995. Four holes were drilled along this access road <br />during the previous investigation. <br />Laboratory Investigation: Samples obtained from the test holes were examined and classified in the <br />laboratory by the project engineer. Laboratory testing included standazd property tests, such as natural <br />moisture contents, dry unit weights, grain size analyses and liquid and plastic limits. The laboratory <br />testing was conducted in general accordance with applicable ASTM and AASHTO specifications. <br />• Results of the laboratory testing program aze summarized in Table 1. <br />Subsurface Conditions: The subsurface conditions encountered in the test holes were highly variable <br />and generally consisted of a layer of granular road base materials or pit run sands and gravels underlain <br />by natural clays or clay fill materials. The granulaz road base materials were encountered at the surface <br />of all the test holes drilled along the Haul Road B Extension and the Fish Creek Borehole Access Road. <br />However, pit run sands and gravels were encountered at the roadway surface in the eastern two-thirds of <br />the West Refuse Pile Haul Road and no gravels were encountered in the western one-third of this <br />roadway. <br />The depth and consistency of the road base materials, as well as the underlying pit run sands and gravels <br />were highly variable across the existing roadways. The depth of the road base materials ranged from 6 [o <br />9 inches along the Haul Road B Extension and from 5 to 9 inches in thickness along the Fish Creek <br />Borehole Access Road. The consistency of the road base materials was also highly variable. The road <br />base materials encountered along the Haul Road B Extension generally consisted of 1 l/2-inch minus <br />base coarse gravels, whereas the road base gravels encountered along the Fish Creek Borehole Access <br />Road consisted of mixed base coazse, pit run sands and gravels and clays. A sample of the road base <br />gravels sampled from the Haul Road B Extension classified as an SM-GM soil in accordance with the <br />Unified Soil Classification System. Whereas, samples of the road base materials obtained from the Fish <br />Creek Borehole Access Road classified as SC-GC to SC-CL soils. The subbase sands and gravels <br />. encountered along the Haul Road B Extension and the West Reftue Pile Haul Road ranged from 6 to 24 <br />inches in thickness and generally consisted of 6-inch minus pit run sands and gravels, which were clayey <br />to silty. <br />Job No. 99-1nnJ Northwcs~ Colorado ConsvltanLt. Inc. Pegc 2 <br />