Many warnings about the North Spur have been ignored.
Dr. Lennart Elfgren and Dr. Stig Bernander, both full professors at the Lulea University of Technology in Sweden, wrote the Minister of Natural Resources on August 1, 2019. In their technical report entitled A Downward Progressive Failure of the North Spur at Muskrat Falls - A Possibility that ought to be investigated and mitigated, dated July 25, 2019, submitted to the Minister, they said that “The most critical inclined progressive downward failure surfaces of the North Spur at Muskrat Falls have not been properly investigated. Relevant stress/strain properties of the metastable soil layers have not been made available, and no independent external experts seem to have reviewed this aspect of the stabilization work.”
They said that old methodology was used to assess the safety of the North Spur, the same model which had been used unsuccessfully at other failure sites, such as Mount Polley, a copper/gold tailings pond owned by Imperial Metals and located in central British Columbia. They repeated their call for an independent panel of experts to undertake the research and to assess the need for further remedial work.
In 2014 a major breach took place at Mount Polley where the storage facility overflowed due to the failure of the embankment. An Inquiry (report entitled: “Report on Mount Polley Tailings and Storage Facilities Breach”, dated January 30, 2015, was undertaken by a Panel led by Dr. Norbert Morgenstern, a geotechnical scientist, as chair of a panel of eminent geoscientists. In its report the Panel concluded:
“ that the dominant contribution to the failure resides in the design. The design did not take into account the complexity of the sub-glacial and pre-glacial geological environment associated with the Perimeter Embankment foundation. As a result, foundation investigations and associated site characterization failed to identify a continuous GLU layer (glaciolacustrine: “Sediments deposited into lakes that have come from glaciers are called glaciolacustrine deposits.”) in the vicinity of the breach and to recognize that it was susceptible to undrained failure when subject to the stresses associated with the embankment…”
“The Panel has examined the historical risk profile of the current portfolio of tailings dams in B.C.and concluded that the future requires not only an improved adoption of best applicable practices (BAP), but also a migration to best available technology (BAT). Examples of BAT are filtered, unsaturated, compacted tailings and reduction in the use of water covers in a closure setting.” (Executive Summary of Panel Report, page 8)
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| (Trees ripped from the roots caused by the tailings pond breach at Mount Polley Mine. Photo: Laurie Hamelin/APTN News) |
The PUB was holding an investigation into reliability issues post interconnection with Muskrat Falls as part of their investigation into “Power Outages and Supply Issues” and the Grand River Keepers (GRK) of Labrador were attempting to inform the North Spur issue by filing expert testimony prepared by Dr. Stig Bernander. I told Dr. Morgenstern NL Hydro had objected to the evidence provided by Dr. Stig Bernander and had asked it to be struck from the PUB record. I also told Dr. Morgenstern that the remediation of the North Spur and attestations of its safety and stability, if any could be found, had yet to be tested in any forum which allows for public input.
I mentioned the work of Dr. Gregory Brooks of the Geological Survey of Canada on seismic activity and landslides, presented to the Joint Environmental Review Panel on the Lower Churchill hydro development, but indicated that subsequent research and remedial action had not been examined publicly. The North Spur received limited attention from the joint panel. This very fact warranted the creation of a forum for its review.
Dr. Morgenstern recognized Dr. Bernander as a credible expert. Dr. Morgenstern said that the commitment to a Mount Polley type panel would be difficult to obtain from government in light of the effort, time and cost involved. He said the Mount Polley panel took six months and cost several million dollars. He said they had requested eight months but the Minister wanted it done in six months.
The following quotes come from the Morgenstern Report into Mount Polley (page 135):
“The breach of the Perimeter Embankment on August 4, 2014 was caused by shear failure of dam foundation materials when the loading imposed by the dam exceeded the capacity of these materials to sustain it. The failure occurred rapidly and without precursors.
“Direct evidence of this failure mechanism is provided by an identified shear surface in surviving remnants of the dam core and by deformations consistent with shearing in a weaker glacially-deposited layer of silt and clay about 8–10 metres (m) below the original ground surface. This layer, its properties, and its extent received intense scrutiny during this investigation, and analyses using representative parameters provide indirect evidence that further supports this failure mechanism.
“Deposited in a complex geologic environment, the weaker glaciolacustrine layer was localized to the breach area. It went undetected, in part because the subsurface investigations were not tailored to the degree of this complexity. But neither was it ever targeted for investigation because the nature of its strength behaviour was not appreciated.”
The report went on to say (page 140) in its recommendations:
“Recognizing the limitations of the current Canadian Dam Association (CDA) Guidelines incorporated as a statutory requirement, develop improved guidelines that are tailored to the conditions encountered with TSFs (Tailings Storage Facilities) in British Columbia and that emphasize protecting public safety.” This was a recognition that the Canadian Dam Association Guidelines do not necessarily apply to all dams, such as the North Spur which is not an engineered and constructed dam.
On May 9, 2017, the Grand River Keeper and the Labrador Land Protectors presented a petition to the Government of Newfoundland and Labrador on the steps of the Confederation Building. The petition, accepted by Minister Perry Trimper on behalf of government, was signed by 1000 people. It called for the appointment of an independent panel of geo-technical experts to undertake research, to assess the safety and stability of the North Spur and to consult widely and publicly. To my knowledge no response was ever given by the government. The panel of experts was to be led by an eminent geo-scientist and to be selected in consultation with community stakeholders in Labrador.
Despite repeated warnings little action has been taken. While Nalcor did engage a geotechnical peer review panel (GPRP) it did not consult with experts nor were local people engaged in selecting the panel or in framing its terms of reference. Drs. Elfgren and Bernander commented on the work of the GPRP as follows:
“Astonishingly, the GPRP did not undertake any stability evaluation of their own. They only provided an opinion solely related to reviewing available data and results based on the concept and the methods used by SLI (SNC Lavalin) and the client. Thus, their assessment of the North Spur stability issues is wrongly based on ideal soil plasticity – i.e. the simplified, so-called Limit Equilibrium Mode (LEM). This model is far from being valid in fully water saturated metastable soil layers. Hence, the GPRP makes no representation regarding the accuracy of the SLI analyses, thus also disclaiming any liability in connection therewith.” (page 5 of Bernander/Elfgren Paper).
Eminent Hydro engineer Jim Gordon also wrote the Minister July 29, 2019. He wrote in support of the work by Drs. Elfgren and Bernander. He said:
“At the base of the Spur there is a layer of soft soil sloping slightly downstream, where a sliding failure could easily occur. The failure would be rapid under the force exerted by the reservoir waters impounded against the Spur. There would be no warning, and no time to evacuate downstream residents.
“Dr. Bernander and Dr. Elfgren have analysed the possibility of such a failure using the low strength of the soft base layer and not the average strength of the Spur soils, since the failure will occur in the weakest layer, not the “average layer”.
“The result is a safety factor well below 1.0 indicating failure. A safety factor of at least 1.6 is required to ensure safety.”
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| Natural Resources Minister Siobhan Coady and Premier Dwight Ball |
The undersigned wrote to Minister Coady on August 1, 2019. In my letter I said:
“We have been told that Nalcor has mitigated all the risks and that we should trust Nalcor to do the right thing. Is there any basis on which the public can have trust that Nalcor has left no stone unturned in its quest to maximize public safety and to minimize the risk of a devastating dam failure or earth slide? Sadly we do not think there is! The public has no basis to trust Nalcor. Do you? If so, you have a duty to inform the public of the basis for your trust.
“As the responsible Minister you carry a heavy burden of responsibility to seek the best advice on how you can discharge your duties and to give appropriate weight to conflicting advice from different sources. In the few short days leading up to impoundment you have to ask yourself whether appropriate weight has been given to the voice of the people who live exposed to the shadow of this existential threat.”
Impoundment of the dam began on Tuesday August 6. Nalcor, on Tuesday, issued the following notice:
“All activities at the Muskrat Falls site required for impoundment (raising water levels in the Muskrat Falls reservoir) have been completed. In preparation of impoundment, we’ve also made changes to the gates in the Spillway. Given recent increased precipitation in the lower Churchill River, water flows are naturally increasing. We anticipate that the water levels in the reservoir will begin to increase later this evening and will rise to approximately 30m over the coming days. We anticipate that by the end of September the water level in the reservoir will reach its final required elevation of 39m.”
I conclude by repeating my challenge to the Minister to defend to the public the basis for her trust in Nalcor in light of their past performance, so graphically exposed during the Muskrat Falls Inquiry: “The public has no basis to trust Nalcor. Do you? If so you have a duty to inform the public of the basis for your trust.”
In particular the Minister must defend the basis for her trust in Nalcor to those people most directly threatened by the North Spur and who live below the dam.
David Vardy
