Quick Clays are unique, sensitive glaciomarine clays. The clay deposits, at the North Spur as elsewhere, occurred when sea water levels were much higher. They are unstable clays. Their peculiar characteristics are known to cause landslides. When Quick Clay is subjected to sufficient stress, the material may liquefy. (Locally, some call the clays "pug".)
|Rissa slide, Norway|
Nalcor's V-P later played defense on the public airwaves rather than produce comprehensive scientific evidence to allay Dr. Bernander concerns.
Part of the concern is that, based on Nalcor's Report, it seems they have used a "static" or what is called a Limit Equilibrium Stability Analyses methodology (which he states does not apply to "long potential slides in slopes with quick clay...") rather than a far more complex "dynamic" methodology, taking into account the different phases of a landslide. This is the approach he pioneered and for which he has received international recognition.
|Recent Slump Feature Near Bottom of North Spur|
LECTURE by Dr. Stig Bernander on "Quick Clay" and the North Spur LSPU Hall,
St. John's, NL October 30, 2014
But Dr. Bernander was able to make one thing clear to every person who attended: the risk of landslides exist not just along the shoreline of the North Spur (the "toe") but much higher up the slope, too.
|Marine Clay, north west of TLH|
near Lower Brook Bridge
Little wonder Bernander would be worried. His eyes are cast a good distance up slope while the Nalcor V-P`s are cast down.
Gilbert Bennett sat down with the Telegram back in August of this year, 2014. He told the Paper to dismiss the importance of the slides upstream and downstream (see photos); he spoke of Nalcor's Plan for remediation of the lower part, the "toe" of the North Spur, stating:
The plan involves flattening the spur by taking material off the top and adding material at the bottom, so that its steep sides are less likely to calve off into landslides. Nalcor will also pile rocks at the base of the spur — essentially building a breakwater — both upstream and downstream of the Muskrat Falls dam to prevent waves from eroding it. On top of that, the construction work at Muskrat Falls involves building a concrete and bromite wall in the ground along the length of the North Spur, which will extend 45 metres below the water level.
The problem is Dr. Bernander believes the plan is not valid because Nalcor may not have used the right analysis to begin with.
Note that Bennett failed to discuss the higher sections of the Spur which extend in excess of 2km up over the steep slopes of the Churchill River towards the Trans Labrador Highway.
Bennett seems not to possess knowledge of the "Progressive" and Retrogressive" slides, which can occur at the higher elevations; the details of which Dr. Bernander devoted much of his Lecture. Bernander warned that millions of cubic meters of sediments can move down over the Spur (or any other embankment comprised of "Quick Clay") once any one of a multitude of forces (water, tremors, blasting, overloading to name a few) become a triggering mechanism.
Gilbert Bennett showed up at Bernander's Memorial University Lecture not to represent Nalcor in a professional capacity but to express ‘pique’; not to show collegiality with the internationally acclaimed expert, or provide a summary of Nalcor's analysis, or as much as offer Dr. Bernander access Nalcor’s data room.
Bennett forgets, too, that the money spent at Muskrat Falls is public money, not his own.
|2014 slide north bank Lower Churchill River|
midway between Muskrat Falls and Goose Bay
If they believe Bernander's claims are credible, knowing he is an expert in his field, they must ask Nalcor for its North Spur "Quick Clay" calculations and be satisfied that the Crown Corporation has competently addressed the issue. This, afterall, is a life safety issue.
It takes a competent and confident organization to willingly submit to critical examination by experts. Nalcor is not that confident; yet there is simply too much at stake to be wrong.
Like "Quick Clay", overstressed, politics is very fluid right now.
But if the Premier should ever get a briefing on what a recognized expert has to say about the risks to the residents downstream of the North Spur and to the project itself, as well as a report on Bennett's exhibition of bad manners, he will act decisively in the public interest.
Hubris must never be allowed to compete with people's lives.
Premier Davis: please tear down the wall of secrecy at Nalcor!