Second day of the hearings dealing with the routing and design of the gas pipeline of the Mackenzie Gas Project. Consultants with Indian and Northern Affairs questioned the proponents’ panel throughout the morning.
Dr. Chris Burn, a scientific consultant with Indian and Northern Affairs Canada, asked how the proponent proposed to protect the peatlands south of Tulita. He noted that these peatlands are typically permafrost and elevated above the rest of the unfrozen landscape. Responding on behalf of the proponents, Rick Luckasavitch responded that in some cases the peat would be compressed to provide a working surface, in some cases leveling or grading would be required, and in other cases fill would used to level out the transition between peatlands and adjacent areas. The determination as to which approach to use would be made on site at the time of construction.
Burn asked what proportion of the pipeline in the discontinuous permafrost zone would occur on cross-slopes up to 10 degrees? Luckasavitch responded that there would be 8 km of slopes greater than 10 per cent (or 7 degrees). Of these cross slopes, 0.5 km of slopes north of Little Chicago would require an ice pad, and 0.5 KM of sloped south of Little Chicago would also require an ice pad
In digging the ditch for the pipeline, some of the spoil may be ice-rich and thus not suitable for use in burying the pipeline. Ice-poor fill (e.g., gravel) would be brought in and used instead in these circumstances. Burn asked how the decisions would be made whether or not to use fill or spoil. Luckasavitch responded that the scope of the program had yet to be determined. He also stated that the information for the detailed engineering is typically gathered after the environment assessment is carried out. This is certainly not always the case. In my questioning the next day, I mentioned the case of the Lysyk panel review for the Canadian portion of Alaska Highway Pipeline Project in the late 1970s and early 1980s.
This pipeline is similar to the MGP in that it was desgined to be a buried natural pipeline through permafrost. The Panel’s 1977 interim report concluded that a pipeline could be built and operated in an environmentally acceptable manner, but identified conditions that needed to be met, including re-routing to avoid sensitive areas, exploring different design modes and proper environmental planning.
The Panel’s 1982 final report was released only after reviewing detailed design submissions from the proponent and technical hearings. In response to questions from Burn, the proponents noted that approximately 964 boreholes along the one-km corridor between Norman Wells and Inuvik. Boreholes are drilled to gather geophysical (e.g., ice content, soil type) and permafrost information to guide site-specific pipeline routing and design.
Paul Cavanagh, representing the Proponents, stated that very few of these boreholes are located along slopes—where the concerns about frost heave and thaw settlement effects are expected to be most severe. Cavanagh also admitted that terrain mapping was used to characterize permafrost along slopes (without the benefit of much borehole data). Chris Heuer noted that the proponent is planning to dig 5000 to 10,000 boreholes along the right of way so as to have geophysical and permafrost data at distances averaging 100 to 200m along the length of the pipeline.
Burn asked whether data from winter 2006-07 and summer 2006 activities for field data collection would be made available to the JRP. Luckasavitch indicated that it would not be. Data would be used for the purposes of obtaining other land use permits and water licences.
Burn asked questions about the use of horizontal directional drilling (HDD) to allow gas pipelines to cross the Kanguk and East Channels of the Mackenzie river in the Mackenzie Delta. Drilling mud at a temperature of 5 to 15 degrees C is used in the drilling process which will melt the side of the drilling hole, especially near the surface where the soils are ice-rich. Joanne Laplante, on behalf of the proponent, admitted a potential for sedimentation effects. (She did not mention other possibly catastrophic events such as pipeline rupture underneath a river channel caused by frost heave in non-permafrost areas adjacent to one or more permafrost areas.)
The question of the engineering design for HDD crossings was clearly an important issue for Robert Hornall, the JRP chair. He asked for more information about the engineering design and possible environmental effects associated with HDD river crossing technology.
Wayne Savigny, a consultant for Indian and Northern Affairs Canada, focused on the assessment of geohazards, such as earthquakes, frost heave, thaw settlement, sinkholes, karst features, and slope-related features. After some discussion Savigny concluded that some geohazards have been assessed by the proponents, others have not. But the susceptibility to some geohazards has not been undertaken. He asked who on the proponent’s team is responsible for geohazard assessment. Luckasavitch repeated the non-answer that he frequently gives to questions about the proponents’ personnel—there is an integrated team of experts who are working on it.
Savigny raised the issue of dynamic liquefaction, which is sudden loss of strength of soil that occurs during an earthquake, and how this phenomenon changes in the context of climate change. On behalf of the proponent, Keith Myer indicated that the question of dynamic liquefaction is a matter of ongoing study by the proponent, that screening analysis is being undertaken for of areas of concern along the route, and that more boreholes may be needed to collect more data.
Savigny noted that northern permafrost may create conditions that are prone to liquefaction that have not been well-documented in the literature. How will climate change be accounted for in this geohazard assessment? he asked.
In discussing the hazards presented by slopes in permafrost environments, the proponent stated that all pipes on slopes exceeding a threshold angle will be insulated. Michelle Laplante noted that terrain stability important to the MGP studied in the EIA. Mapping has identified various landslides, avalanches, sinkholes, karst features, has been done
Savigny went on to comment that the Norman Wells proponent (as well as MGP proponent) had promised to maintain a positive “roach” (a small hill on top of the pipeline) in order to ensure that water drains away from the pipeline. Enbridge has abandoned that commitment for cost reasons. Luckasavitch responded that the MGP’s commitment is limited to the first few years after construction.
Savigny asked how the project team is organized to ensure effective communication among team members. He followed up by asking whether or not the proponents had considered establishing an external review board, as has been done for other big projects. Luckasavitch responded that external consultants were sometimes used (but no external review board).
Savigny asked what the accepted incident frequencies for the MGP gas pipeline and natural gas liquids pipeline are (as measured in incidents per thousand kilometre years). He explained that an incident is a problem in the pipeline that requires an intervention on the part of the pipeline operator. He indicated that in non-probematic environments, the incident rate caused by geohazards .02 to .05 incidents per thousand kilometres. In more difficult terrain, this rate increases by one order of magnitude. In the most difficult terrain, the rate increases to 2.0 incidents per thousand kilometres. He asked what the proponent’s objective is. Luckasavitch responded that the proponent doesn’t have one.
Savigny asked if the proponent had calculated an annual accepted probability of failure. Luckasavitch responded that work is underway and that a workshop has been held. Tens of interventions are needed to ensure the integrity of the pipe.
Savigny also noted that the proponent is relying predominantly on boreholes drilled by others, not ones it has drilled.. He then asked if the proponent is taking a responsibility for this data base. The answer from the proponent was yes; there has been periodic vetting of the data each time it is used.
My reflections on the day are that there are a number of serious technical issues raised by the INAC consultants. Much of the data to test the validity of their concerns has yet to be collected, and that data will not be available until after the JRP has concluded its work.