Base de données de recherche des TNO

Régions: Inuvialuit Settlement Region

étiquettes: physical sciences, petroleum industry, land use planning, geotechnical survey, industrial development, site reconnaissance

Objectif(s): The objective of the proposed fieldwork is to gather information to develop a suitable knowledge base for project planning, assessment of impacts and drafting of environmental protection plans related to the development of the Niglintgak natural gas field. Additionally, time in the field will be used to conduct some routine maintenance at Camp Farewell.

Description du projet: The proposed fieldwork is an expansion of previous years' fieldwork to develop a suitable knowledge base for planning and development. In addition, some routine maintenance at Camp Farewell will be conducted. The majority of the proposed work is planned for the Niglintgak area and is focused around the Gas Conditioning Facility (GCF) and the Horizontal Directional Drilling (HDD) crossing site, as well as the Kittigazuit S-Bends, Camp Farewell, and in Tuktoyaktuk. Auger drill rigs will be used where the ground is frozen but does not contain boulders. Soil samples are taken at selected intervals with this method. An air rotary drill rig will be used where boulders are encountered or the ground is frozen. Both these methods of drilling do not require drilling fluids. An area of approximately 10 m x 10 m (0.01 hectares) is required to drill each borehole. Boreholes will be backfilled to the original ground surface with drill cuttings. A combination air/mud rotary rig using a combination of water and betonite will be used for deeper holes that have a high potential for shallow gas. The rig is equipped to a diverter head to safely exhaust shallow gas. As well, this rig is used for drilling in water because it has the capability of causing no environmental issues in the river system. A geotechnical survey will be conducted to collect information on permafrost. Thermistors will be installed in boreholes, and the depth of the active layer and the boundaries of thick ice will be determined. The ground temperature data will provide baseline information for designing pilings. Boreholes will be drilled at various locations around the site, and will be used to address HDD alignment and scope changes that have occurred since the 2005 geotechnical survey. Data loggers will be connected to thermistors until the start of construction, when any thermistor holes that are in the way will be removed by disconnecting the data logger and cutting off the plastic tube and cable at ground level. Material from some of the boreholes will be collected as representative of the sediment that will be excavated and disposed of during the preparation of the site. Shallow sediment sampling will be conducted at the test pit location. Samples will be collected at the surface and at a depth of 2 m using hand tools or hand-held power tools above the river water level. They will be analyzed for particle size, moisture content, total organic content, metals, and hydrocarbons. A test pit located below the high water mark will be excavated using an IronWolf Crusher to conduct permafrost degradation testing to test an insulated foundation designed to protect permafrost. The excavation will also test the performance of the IronWolf in the winter climate conditions. If necessary, a snow berm may be erected around the pit. After test excavation, a small insulated foundation and temperature monitoring equipment will be installed. A data logger will monitor temperature and peak water levels. Sedimentation above the foundation will be monitored throughout the 2007 spring break-up and summer periods. Prior to spring break-up two lines of three to four sediment plates will be secured to the ground in the vicinity of the test pit. After spring flooding sediment plates will be retrieved. Upon completion of the monitoring, the test pit will be remain in place and allowed to sediment back in with flooding. The option of disposal of excavated material on the ice in Kumak Channel will be investigated. The Mackenzie River has high natural sediment loading during spring freshet and it is expected that the net increase due to the excavated material would be negligible. Test pit material will be disposed on the ice only if lab analysis of sediment samples determines that background analytes are below the acceptable criteria. Observations will be made on how the ice in Kumak Channel melts, how the excavated material is carried and where it is deposited. A benchmark will be installed and will provide a reliable vertical datum control point. Benchmark installation consists of drilling a 10 m hole and placing a central rod within a steel sleeve. A ground penetrating radar bathymetry survey will be done at Niglintgak stockpile approach from the surface of the river ice. An area of Kumak Channel will be cleared from the end of the ice road to the stockpile site. An ice profiler with GPR equipment will be pulled behind a truck or snow machine to collect bathymetric information on the approach to the stockpile site. Spring break-up peak water level will be monitored and flood depths measured in the vicinity of the site. Confirmation of peak water levels is needed to ensure the planned structure is above the maximum water levels. Kittigazuit S-Bend area sediment sampling will focus on areas that would require dredging and where disposal of the dredged material may occur. Samples will be collected from the upper 10 cm of the river bottom sediment, and from at least two depth horizons, including surficial and the deeper layers. The vertical extent of proposed dredging is 2 m depending on location. Crew will travel from the ice road to the various sampling locations by tracked vehicle and skidoo. Ideally, no snow clearing will be done and the sample site can be prepared using a 0.2 m or 0.3 m power auger to drill through the ice. Cores will be collected from the ice surface. Parameters to be analyzed include metals and metalloids (including methylmercury), polycyclic aromatic hydrocarbons, sulphides, grain size and organic carbon content. Coring will confirm data collected in previous field seasons and evaluate physical and chemical properties in the areas likely to be dredged. Sediment samples will supply additional information regarding the potential contaminants. The Kittigazuit S-Bend sediment sampling program will be carried out in accordance with recommendations made by Environment Canada. Camp Farewell general maintenance activities will include: removal of six mooring piles, installation of three new mooring piles, and repair of the winter access road from the dock/ice road to the camp area. Testing to identify the most effective GCF ballast tank for the northern climate will be conducted at a facility in Tuktoyaktuk. An experimental tank will be designed and fabricated. The tank will be 6 m high with a 4 by 4 m base, with four compartments of equal size. Each compartment configuration will be monitored to see how effectively pressure is relieved throughout the freeze/thaw process. Local workers will be used from early October 2006 through the spring of 2007 to install and monitor the tank. Monitoring is likely to continue beyond 2007. Field work will be conducted between January to April 2007, however monitoring equipment for the spring flooding at the Niglintgak site as well as equipment for monitoring at the excavation test pit and the ballast tank freezing simulation will left in place for 2007 and possibly beyond. For the work being conducted at Niglintgak and Camp Farewell, field crews will be based at the permanent camp at Camp Farewell. To access the Niglintgak field development area and Camp Farewell, a dedicated ice road will be constructed from Bar-C (Tununuk Point) to the Niglintgak Field Development Area. Some water needs will be taken from Middle Channel and Kumak Channel. Water withdrawn from the Mackenzie River will be screened with 2.54 mm fine mesh to prevent entrainment of fish. Waste will be either incinerated or transported for disposal in the Inuvik landfill. Sewage and greywater will be transported to Inuvik sewage treatment lagoon. Waste generated at Kittigazuit will be transported to Tuktoyaktuk for disposal. Fieldwork will be carried out from January 1 to April 30, 2007.