080121-08MN006-Sabina Hackett River Project Proposal ... - NIRB

Project Description• design a horizontal alignment with large radius curves for vehicle safety• avoid cuts in hillsides, which will become areas of slides and continual melting• build the road on the south sides of valleys to maximize heat from the sun• avoid cuts that could become areas of melting permafrost and locations of deep snowdrifts• design a vertical alignment that will be swept clear of drifting snow by prevailing winds• avoid stream valleys because of flooding• place the road on ridges or benches to minimize sidehill cuts and drainage problems• follow the contours of hills if possible• provide adequate culverts, ditches and sedimentation ponds to manage storm watereffectively and prevent erosionDuring this phase of the design, the alignments of the access road will be discussed andcoordinated with the appropriate environmental groups.2.8.2.4 Design StandardsProvincial geometric low-volume road standards (for example, from British Columbia or Alberta)will be selected that are appropriate for the proposed design speed and the intended use and lifespanof the road.The gravel surface of the road will be designed to a suitable standard to accommodate year-roundheavy truck traffic (40 return trips per day), at a design speed of 80 km/hr. Each truck will becarrying a 40-tonne load and the overall gross vehicle weight will be 65 tonnes.2.8.2.5 Construction and Operation of RoadRock for road construction will be quarried in areas close to the alignment and placed as aminimum 1 m fill on the original ground to form the road embankment and provide insulationover the permafrost. The ground will not be stripped, and the existing vegetation will be left inplace to provide further insulation to the permafrost. Because road building equipment will notbe allowed to run on the tundra in the summer for environmental reasons, the road will be built inthe winter or by end-dumping in the summer.Cross-road culverts will be installed at watercourses and in embankment areas to prevent waterfrom ponding along the embankment, which would cause the permafrost to melt.2.8.3 Bridges Over the Hackett River and Large WatercoursesThere will be a number of bridges over the Hackett River and large watercourses. Preliminarytasks before road alignment begins will include the selection of the most suitable water crossingpoints.January 2008 Hackett River Project – Project Proposal Sabina Silver CorporationReport Version B.1 2–38 Rescan Environmental Services Ltd. (Proj. #833-2)