NWT RESEARCH DATABASE

Regions: Inuvialuit Settlement Region, Gwich'in Settlement Area

Tags: physical sciences, feasibility study, all-weather road

Objective(s): To determine the feasibility of construction of an all weather access road, creek crossing and pads in the Study Area.

Project Description: This licence has been issued for the scientific research application No.4738. The objective of this project is to collect sufficient information to determine the feasibility of construction of an all weather access road, creek crossing and pads in the Study Area. The results of the 2018 ATCO studies show that the development of the area can be done in a manner that would protect the environment. As a final step in assessing the feasibility of the area for development, the Inuvialuit Regional Corporation (IRC) now needs to assess the ground conditions at the site for foundation, load bearing and drainage design purposes. To accomplish these objectives, IRC now proposes to complete the 2018 (test pit) geotechnical investigation with an auger-based drilling program. The proposed geotechnical field program includes drilling approximately 18 shallow boreholes within the Study Area to depths of 5 to 20m at select locations along a proposed preferred access road alignment, at proposed preferred and alternate creek crossings, and at a proposed infrastructure pad location. The 2018 ATCO study indicated several feasible routes for an access road and raised several questions about the best alternatives for pad design. Shallow geotechnical auger drilling will answer these questions and allow the team to proceed with better design that is more protective of the permafrost, the land, and the water flow. The proposed 2020 Feasibility Study would be undertaken during freeze conditions and prior to bird migrations this spring. The goal is to undertake the studies between March 15 and May 1 2020. The program will include 3 steps: 1) Wildlife Screening - screening of the proposed route for bear and wolverine dens. This task will be carried out in March by Inuvialuit wildlife monitors on snow machines. If dens are located in the Study Area they will be GPS’d and documented. No bears, wolverines or any other animals will be disturbed. 2) Temporary winter access road compaction - Using the findings of the den survey and the 2018 field work, the two proposed routes through the Study Area will be finalized to enable the most ecologically sound winter access for the mobile drilling rig. Site access will be constructed in advance of drilling operations using standard practices for temporary winter access road construction. All investigation (borehole) sites will be accessed by ground transport along compacted snow roads. All equipment and crews will be transported to and from the site via the Inuvik to Tuktoyaktuk Highway (ITH) and winter access roads. Temporary winter access road construction practices will adhere to Northern Land use Guidelines and best practices. Tracking of the routes through the snow pack will be completed by Low Pressure Ground (LPG) equipment in order to protect the permafrost. A spray of water may be used to hard top the track after packing is completed. This water will be obtained in Tuktoyaktuk and will not require lake water nor a water licence. The routes have already been surveyed and are clear of heritage resources and rare plant species. The creek channel width ranges from 6.9m to 9.0m and will be frozen. It is necessary to drill and investigate the surficial soils near the creek in order to plan the best design for a potential all-weather crossing in the future. (I.e. culvert or bridge and sizes). Boreholes will be drilled along the creek bank, not in the stream channel. No drilling activities will occur in the channel. 3) Once the hard-track is in place, the geotechnical engineering firm will advance through the site with a mobile auger drilling rig, specialized for arctic permafrost drilling. The drilling program will be completed using a track-mounted, ground-based, auger drill equipped with 150 mm (6”) diameter solid stem augers, 100 mm (4”) diameter CRREL barrels (Cold Regions Research Engineering Laboratory), and 50 mm (2”) diameter SPT tube samplers. The auger and core drilling will be completed using a track mounted Prospector P1 Multipower auger top drive drill, which has been successfully used for previous programs. No drilling fluids or water will be required for drilling. The research team expect to drill approximately 18 boreholes. The team expect that all auger/drill cuttings will be frozen. Drill cutting samples will be collected and sent south for lab testing. After completion of a borehole, the borehole will be backfilled with auger drill cuttings, ensuring down hole bridging does not occur, and any excess cuttings will be mounded over the hole. If supplemental backfill material is required to completely backfill a drill hole, then granular material sourced from Tuktoyaktuk or Inuvik will be used. The research team propose to install ground temperature cables (also referred to as thermistor strings) along the proposed access road alignment, at the proposed creek crossings and at the proposed infrastructure pad to collect ground temperature data for monitoring temperatures within the Study Area, site evaluation and design requirements in support of the feasibility assessment. The ground temperature data collected from the installations will be used to determine ground temperature profiles, active layer thicknesses, and mean annual ground temperatures, similar to those placed along the ITH. To accommodate the ground temperature cables, a 25 mm diameter PVC pipe will be installed in each borehole, and a 150 mm to 200 mm diameter protective surface casing will be placed around the PVC pipe to protect the instrumentation. Up to 5 ground temperature cables will be installed within boreholes. All results will be reported back to the Tuktoyaktuk and Inuvik Hunters and Trappers Committees. While on site, all crews will be experienced and trained in wilderness safety and a project specific safety and environmental protection plan will be in place. All crews will be equipped with satellite phones or utilize the Garmin Inreach service if cellular phones are out of service. An Inuvialuit wildlife monitor will be present at all times. The fieldwork for this study will be conducted from March 15, 2020 to April 30, 2020.