A fine paper at the Banff, Alberta conference on Tailings & Mine Waste is that by John Sobokowiczand Norbert Morgenstern. It is called “A Geotechnical Perspective on Oil Sands Tailings.” In fact it would be a great paper if the presentation (soon to be available on the conference web site) had notfocused on the Alberta Energy and Resource Conservation Board (ERCB). Recall the ERCBhave concocted that utterly ridiculous requirement that oil sands tailings have a strength of 5 kPajust one year after placement!

Of course the ERCB deserves all the attention directed at it during this conference, for they have truly perpetrated one of the most absurd regulations ever to hit the mining industry. The ERCB has displayed for all the world the utter ineptitude and incompetence of regulators in protecting the public and the environment.

Now at lastconsultants (Sobkowicz) and professors (Morgenstern) have woken and taken on their allotted task of intellectual leadership—they publish the paper to which I refer.

You will have to read the paper and see the presentation to appreciate the awakening of folk who prefer to travel to exotic places in preference toreigning in the excesses of silly regulators. At least, at last, on the topic of the strength of oil sands tailings, they write–stating the obvious:

The strength of a tailings material varies with its grain size distribution, clay content, clay mineralogy, water chemistry and solids content. At low solids contents, the tailings acts as a slurry (i.e., as a “liquid”) with a very low yield stress under shear. As the solids content increases, the yield stress at first increases very slowly, and then at some point, increases very quickly, after which the tailings acts more as a solid.

The authors acknowledge that the best measure of when an oil sands tailings changes from a liquid to a solid is that very old geotechnical parameter, namely the Liquid Limit (i.e., on of the so-called Atterberg Limits.) They say on this topic - and thereby provide a much more rational measure of the strength, hence resistance to flow in the event of a breach of the containing embankments:

A simple geotechnicaltest (“Atterberg Limit”) can be run which, for small cost, provides much insight into the relationship between solids content and tailings strength. This test has been almost ignored, or at the least highly underutilized, by industry.

There you have it: non-geotechnical engineering regulators, unaware of the basics of geotechnical engineering, setting regulations in the absence of geotechnical science or engineering, even the most basic sort. A sad story and one that will cost the industry an incredible amount of money and trouble as they blunder through the mists of ignorance.

We can only applaud the awakening of people of knowledge and intelligence and their statements on the science of reality. For keep in mind that the ultimate objective of the ERCB regulation is to preclude the uncontrolled flow of liquid tailings through a breach in the surrounding embankments. The ERCB picked a totally inappropriate, terminally vague, parameter, 5 kPa, as a metric of non-flowability from a breached tailings impoundment. Here at last we have academia weighing in on the fact that the Liquid Limit would be a better, easier to measure, more representative parameter to supposedly protect human health and the environment. That is if you accept that legislating unflowable tailings is a way to prevent escape of tailings in the event of a dike breach.

Personally, I would have thought that it is far more rational to mandate dike integrity and allow time and gravity to do the work of rendering the tailings unflowable. But of course even that will have no impact in the long term - for then geomorphologic change will have its way regardless of Liquid Limit, shear strength, ERCB, or academic action or inertia.

In the meantime the regulators will scurry in silliness; the industry will scramble to meet the impossible; academics will make pronouncements on the basics; conference attendees will snooze through presentations; and nature will laugh at this human folly - at the sight of a whole society that lost its head in the absence of wise leadership and brave people.