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• INTRODUCTION <br />The proposed Bowie No. 2 Mine haul road, facilities and portal aze to be constructed in a less <br />than ideal location. The road and surface facilities will be situated on an ancient landslide within <br />steep terrain formed by horizontally interbedded sandstone and shale of the Mesaverde Formation. <br />Because of this location, BRL and the DMG are very concerned about the stability of the road <br />and facilities during the operational stage of the project and after reclamation. <br />In order to address the stability of the road and facilities, geotechnical studies were performed. <br />The following sectiogs of this volume present the results of the geotechnical studies conducted at <br />the Bowie No. 2 Mine site. The studies were conducted for the purpose of evaluating <br />geotechnical-related issues pertaining to site design, construction and most importantly, long-term <br />post-mining reclamation stability. <br />BRL commits to implement all the recommendations presented in the enclosed geotechnical <br />studies prepared by Maxim. BRL's commitments outlined below are merely presented to <br />accentuate some of Maxim's important geotechnical recommendations. <br />Preliminary Geotechnical Engineering Study <br />• This report produced by the preliminary geotechnical engineering study (Tab 2), summarized the <br />data obtained during a Seld exploration program consisting of soil sample collection from 23 <br />exploratory borings scattered throughout the site. Design parameters and a discussion of <br />geotechnical engineering wnsiderations related to planning and development are included in this <br />report. This study described the predominate subsurface materials as ancient landslide deposits of <br />very stiff to hazd, slightly moist, lean clay with gravel and scattered to numerous small to very <br />lazge rock fragments. Soils tests revealed generally high internal cohesion strength, with test <br />results from 900 psf (tow strength) to almost 29,000 psf (high strength), with the average of 12 <br />tests being 12,800 psf (high strength). The angle of internal friction ranged from 4 degrees to 23 <br />degrees. Most of the clays on site would be considered sensitive to loss of strength and/or <br />volume change upon increased moisture content or pore pressure. The in-place density of the <br />material averaged around 115 pcf. in-place moisture content varied between 10 and 24 percent <br />with an average of about 15 percent, which is wnsidered somewhat dry of optimum for the <br />material. Some plastic clays were sampled which would be considered highly expansive with <br />percent swell measured at 8 to 13. <br />The preliminary geotechnical engineering study concluded with numerous recommendations <br />which where incorporated into the design of the site where possible. Cut slopes at the site should <br />not be steeper than 2:1 (horizontal to vertical) unless they are constructed in very stiff to hazd <br />clays above ground water where slopes as steep as 1.5:1 would be acceptable. The slopes should <br />be vegetated and any areas of ground water seepage will require drainage blankets. Fill slopes <br />should be no steeper than 2.5:1, although, slopes at 2:1 would be acceptable in areas where risk <br />L_J <br />-1- <br />