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The five pictures in this posting, were taken (by me) at the Getty Center in Los Angeles.  This place is surely a testament to genius and attention to detail.

Yesterday I was asked if Canadian guidelines are adequate to deal with the Mt Polley situation. More specifically, the questions continued: if the current Canadian guidelines regarding tailings dam safety had been implemented, would the failure have been avoided. Before I answer these questions, let us first take a look at the guidelines that are out there.

APEGBC, the Association of Professional Engineers and Geologists, of British Columbia on their website say this:

APEGBC recently published professional practice guidelines for dam safety reviews: the Professional Practice Guidelines – Legislated Dam Safety Reviews in BC, which were commissioned by the BC Ministry of Forests, Lands and Natural Resource Operations. The Guidelines define the professional services, standard of care and specific tasks to be provided by APEGBC members conducting this type of work; provide descriptions of the roles and responsibilities of the various participants/stakeholders involved in a dam safety review; and set out expectations for the appropriate knowledge, skill sets and experience to be held by APEGBC members working in this field. The Guidelines also aim to address consistency in the reporting prepared by APEGBC members providing professional services in the field of dam safety reviews.

The Mining Association of Canada has published two guidelines for tailings facilities. These are described well at this link in the following terms:

In 1998 the Mining Association of Canada (MAC) published A Guide to the Management of Tailings Facilities. This guide was prepared by the Canadian mining community and is designed to assist mine operators in developing a successful management system for their tailings facilities. It covers each stage of tailings management from design through construction, operation and then closure and reinforces the integrated nature of each element. Its purpose is to provide information on safe and environmentally responsible management of tailings facilities, to help mine operators develop tailings management systems that include environmental and safety criteria, and to improve the consistency of application of sound engineering and management principles to tailings facilities.

MAC published a follow up manual in 2003 entitled, Developing an Operation, Maintenance and Surveillance Manual for Tailings and Water Management Facilities. This manual was developed to compliment the 1998 guide with a view to focusing on the day to day operations of a tailings facility. The need for this manual became apparent in 2000 when mining companies were demonstrating a significant progress in adopting and implementing tailings management systems. The manual draws on sound industrial practice and procedures and was prepared by tailings experts within the Canadian mining community.

In 1999 the Canadian Dam Association (CDA) revised its Dam Safety Guidelines to include tailings dams. MAC and other contributors helped to develop and incorporate tailings facilities into CDA’s guidelines meaning they now have the same level of respect as conventional dams. Martin et al. (2002) report that the revised guidelines focus on the responsibility for dam safety, scope and frequency of dam safety reviews, the need for an operating manual and emergency planning.

The MAC guide and manual and the CDA guidelines are intended to complement government regulations and promote due diligence of a mineral operator. The overall goal is to protect the environment and the public from the hazards associated with tailings storage.

The MAC guide and manual and the CDA guidelines are intended to complement government regulations and promote due diligence of a mineral operator. The overall goal is to protect the environment and the public from the hazards associated with tailings storage.

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Then there are documents on the same subject from the Canadian Dam Association. Their website notes as follows:

 CDA has developed Dam Safety Guidelines and related technical bulletins that have become primary  references for dam owners, operators and regulators. The CDA Mining Dams committee has developed  additional guidance on dam safety for tailing dams and other mining dams, following a three-year period  of input, review and comment. The new publication – Technical Bulletin, Application of Dam Safety  Guidelines to Mining Dams – addresses technical aspects of mining dam safety. This Bulletin will be  released at the annual CDA conference to be held from Oct. 6 to 9, 2014. Further guidance on  management and operation of tailing dams is available from the Mining Association of Canada.
There has been some confusion in the media with respect to CDA’s role in the regulation of dams. CDA  publishes guidance on the design, construction and safe operation of all dams including tailings dams. In  Canada, the licensing and regulation of dams is under provincial or territorial jurisdiction. While our Dam  Safety Guidelines and technical bulletins provide valuable assistance to regulators, dam owners and dam  managers, they are neither standards nor regulations. The Canadian Dam Association has no regulatory  authority.   The Mount Polley tailings dam failure illustrates the need for continual vigilance among mine owners,  dam safety engineers, operators, and regulators. The Canadian Dam Association supports efforts to  advance understanding and practices to improve safety at all dams.

In the past year I have done dam safety inspections for eleven tailings facilities from northern Quebec through the USA and Central America to South America. Obviously I read the guidelines noted above in detail before undertaking this task, and many times during the work.

My opinion: the guidelines are all good and informative, but they are timid. They were written by those sympathetic and beholden to the mining industry and thus they were written so as not to offend anybody in mining. They were written to encourage miners to do better. But they make no demands that involve too great an effort or expenditure.

Another opinion: if you need these guidelines to tell you how to undertake a dam safety inspection, you better not undertake the dam safety inspection, for the guidelines are far below the degree of experience and expertise needed to undertake a professional, thorough, and competent dam safety inspection.

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To take one example. There is a call in the APEGBC document for peer review. This is how it is stated:

An independent peer review is an additional level of review beyond the minimum requirements of Bylaw 14(b)(2) that may be undertaken for a variety of reasons (such as those listed in section 4.3) by an independent Qualified Professional Engineer not previously involved in the project. At the discretion of the Qualified Professional Engineer, in consultation with the reviewer(s) involved in the regular checking/review process outlined above, such an additional level of review may be deemed appropriate.

Alternatively, a local government or other approving authority may request an independent peer review to support project approval. An independent peer review may be undertaken by another Qualified Professional Engineer within the same firm, or an external Qualified Professional Engineer.

The independent peer review process should be more formal than the checking/review process carried out under Bylaw 14(b)(2). An independent peer reviewer should submit a signed, sealed and dated letter or report, to be either included with the dam safety review report or put on file, which includes the following:

  • limitations and qualifications with regard to the independent peer review; and
  • results of the independent peer review.

When an independent peer review is carried out, the Qualified Professional Engineer who signed the dam safety review report remains the Engineer of Record.

The independent peer review discussed above is not the same as an independent review or advisory service provided by a Qualified Professional Engineer who is retained by the Regulatory Authority, or sometimes a client.

Pusillanimous, is all I can conclude.

So sadly, I must conclude that even if the guidelines had been fully implemented at Mt Polley, which I am sure they were not, the failure probably would not have been avoided.

Fact is folk, that the best standards of practice internationally on big and important tailings dams involves at least the following:

  • An annual report by the Engineer of Record on what was done at the dam by way of design, construction, deposition, and instrumentation during the preceding year.
  • A report by an independent and different engineering firm of the status of the dam. In South Africa as a result of the Bafokeng and Merrispruit failures, this is done every three months.
  • Annual or more frequent meetings by an independent panel of three senior peer reviewers. All the oil sands tailings impoundments have peer review boards. Nordie Morgenstern, to my knowledge, sits on those of Suncor and Syncrude.

I bet you none of this (these?) are done on any BC tailings dams. Certainly they were not done at Mt Polley. And none of the guidelines I mention above mandate these actions. Why? As I noted, to do so would offend the mining industry and result in rejection of the guidelines.

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Sad but true. Thus I must conclude that the new independent review panel must find that the international standards of review were not followed, that Canadian guidelines do not mandate the same, and that if we are to preclude future failures of Canadian tailings facilities (four in the past two years) we are going to have to make major changes to the way we work.

This is not a matter or one in a million as Dirk van Zyl says. It is a matter of one in five thousand—each and every year and thus worthy of major attention and change.

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We are heartened by today’s announcements re the Mt Polley tailings facility failure.   I particular we applaud the choice of experts retained to do the engineering review.

CBC New reports as follows on this issue:

Minister of Energy and Mines Bill Bennett says the B.C. government is setting up two separate reviews following the Mount Polley tailings pond failure earlier this month.

Bennett said Monday that:

  • The first review by three independent experts will investigate the failure of the tailings dam at the Mount Polley mine.
  • The second review will require all mines in British Columbia that have tailings dams to have independent experts conduct a review of their facilities and submit them to the government.

The first review will be completed and submitted to the government and the Soda Creek and Williams Lake Indian bands by Jan. 31, 2015, and the recommendations will be implemented by the government “where needed,” Bennett promised.

The minister said the reviews were necessary to restore public confidence in the mining industry.

“We have a responsibility, as the jurisdiction where this failure took place, to find out exactly why it happened, ensure it never happens again and take a leadership role internationally in learning from this serious incident,” Bennett said.

When asked what might have caused the dam to fail on Aug. 4, Bennett said there is no “leading theory” yet.
The three experts appointed to review the dam failure are:

  • Norbert Morgenstern, an adviser to consulting engineers.
  • Steven Vick, a geotechnical engineer from Colorado.
  • Dirk Van Zyl, a professor at the University of British Columbia’s Normal B. Keevil Institute of Mining Engineering.

Zyl called the the failure of the tailings facility at Mount Polley ” a dark day for the mining industry not only here in British Columbia, but worldwide.”

“It’s extremely important for us to understand how this breach happened and why so that we can move forward with the best possible practices in ongoing and future mining operations,” he said.

I do not believe a better panel could be found.  Morgenstern is the leading Canadian expert on tailings dams.  I first came across his name at university in the 1960s when we studied his theories for foundation design.  I have made presentations to him in his capacity as a peer reviewer to Suncor on their tailings facilities.  I have read many of his reports and listened to many of his lectures. He is old but still wise and sharp.  He is an expert of repute..

Steve Vick I first met in the early 1980s when we were working on tailings facilities in Colorado.  On an old posting on this blog I wrote this about Steve: Steven Vick’s great book is Degrees of Belief, Subjective Probability and Engineering Judgment.  This is the book that started and still underpins any enquiry into the nature of tailings facilities and their management via an understanding of the role of probability, judgment, and ultimately decision making in the mining context.   And of course there is his book Planning, Design, and Analysis of Tailings Dams.  I have read it again and again over the years for it is full of wisdom.  Read his paper at this link to see how thorough he is.

Writing in 2012 about Steven Vick, I said the following:

Risk is the product of probability and consequence.  In the long term, as time proceeds to infinity, the probability of an adverse event tends to one.  When seeking to control the risk of long-term tailings facility failure, there is little we can do about the probability of failure.  In the goodness of time it will occur.  All we can do today, is to seek to limit the consequences of failure, adverse performance, and unacceptable impact.

Steve Vick reminded us of this inescapable conclusion in a magnificent keynote address at the Tailings & Mine Waste 2012 conference just ended in Keystone, Colorado.   The authority and reputation of Steve, who is surely the doyen of tailings, ensures that his insight will force a change in the way we think about and act as tailings engineers.

Steve reminded us that the consequences of failure of a tailings facility go well beyond the physical impact of tailings that may escape the failed facility and impact the receiving environment.  The consequences may include significant and even total loss of shareholder value, the closure of the mine, the shutting down of the company, and huge financial expense to society.  And of course, there is loss of life, loss of reputation, and loss of industry credibility.

What can we do to minimize the consequences of failure of tailings facilities?  The best is to undertake filter-pressed, dry-stacking.  In the long term, things may move, but not flow—the worst consequence of failure.  Put the tailings in a place where the inevitable migration of material and constituents is to an accepting environment.  Avoid downstream rivers, lakes, and oceans.

Steve noted that in all cases the tailings facility will eventually become the ward of the state (society).   Only in the case of the UMTRA Program is there a supposedly perpetual government agency charged with looking after the closed tailings facilities: twenty-four old uranium mill tailings piles.

Steve noted that only European cathedrals have cultural value sufficient to induce society to care for them in the long term.  Closed tailings facilities will never be such icons of cultural respect.  Of course we can turn the closed impoundment into a riding stable as was done at the Cannon Mine.  But not all closed tailings facilities lend themselves to such conversion into socially beneficial places.

The inevitable conclusion from hearing Steve is that some mines just should never open.  Some tailings practices are going to have to go the way of the dodo.  His best example is a water cover.  And maybe hydraulic fill in places where the tailings will not be totally dry or frozen forever.

Maybe we should get Steve to head up an international evaluation of how to undertake tailings practices that result in long-term, tolerable consequences.  I suspect that if he or others do not do this, we will see no change in the rate of tailings facility failure and long-term negative consequences for too many places.  Why we may see the demise of  mining and society as we know and enjoy it.

I will credit anything he concludes.

Dirk Van Zyl is a long-time colleague and friend.  I took his job many years ago when he left SRK to come to the USA to do his doctoral thesis.  We are still working together on organizing conferences for InfoMine.  Dirk is quoted in one report as follows:

UBC Engineering Prof Dirk van Zyl says failures like this are about one in a million per year.

“…you always hope it never happens at home and  this time it did and so it’s a great force that’s released when you have such a failure

van Zyl says large failures like this and investigations of them often find there could be a number of ways the breach could have happened.

Actually his statistics are off by a thousand or two.  Franco Oboni of Riskope writes the following in a comment on a previous posting on this blog:

On a portfolio of approximately 3,500 tailings dams world-wide we evaluated that in the decade around 1979 (1974-1984) the rate of failure was 10-3 (one dam in one thousand per annum on average) and the decade around 1999 (1994-2004) the rate of failure was 2*10-4 (two dams in ten thousand per annum on average). Those numbers mean respectively 3.5 major dams breach in average per year (1974-1984), 0.7 major dams breach in average per year (1994-2004). With those averages one could easily evaluate the probability of having more failures in one year, but we will leave this aside, for the moment. Again, we do not know if 3,500 is still correct, but we assume it is for the sake of the discussion, and there is no clear definition of what a major breach is, so we assume these are the most widely reported failures, that reach even non expert public through media exposure. The validity of the 3.5-0.7 range can easily be “verified” by looking at the Chronology of major tailings dam failures as published, for example, by Wise-Uranium in their website. As such, the decrease from 3.5 to 0.7 can be seen as an indicator of the mining industry performing overall a better job today than it did in the past, but we will also leave this discussion to another time.

Many hazardous industries (chemical, electrical, for example) around the world consider the limit of credibility for an accident at a probability in the range of 10-5 to 10-6 (one in hundred thousand to one in a million). By the way, hydro dams have historic record of failure floating around the credibility threshold. Thus tailings dams are to be considered more hazardous than hydro dams, and they unfortunately cannot be breached at the end of service life: they have to stay there “forever”. Obviously, with the estimated values of the prior paragraph, major tailings dams breaches are to be considered way above credibility now, and more so, in the longer run, although long term consolidation may help a bit.

No matter.  Mt Polley simply confirms that there are two to three tailings failures per year.  We had Duke Energy earlier this year and probably one more to go before Christmas.  Well before the panel presents its findings.

The only misgiving I have is that these three gentlemen are extremely busy without the added burden of this panel work.  Where will they find time to do it all?  I suppose the answer is the old adage: if you want good work done, ask only those too busy to do it.

So we wish them speed and success at finding out why Mt Polley’s tailings facility breached.

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I have lost count of the number of radio stations, newspapers, and magazines that have contacted me asking for opinions on the Mt Polley tailings happenings.  Somehow the email from Adrian Lee of that most reputable of Canadian magazine, McLeans, had a air of intelligence the pulled me into replying.  (I confess to being a regular reader of McLeans.) (more…)

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Here are the stories of the seven dam failures that have occurred since the beginning of 2012. Six are failures of tailings facilities. The seventh is a rockfill dam. The following are extracts from technical papers that I wrote well before the Mt Polley failure. Details of the first three are available at this link. Details of the remaining four are in a paper that I will present at the Tailings and Mine Waste 2014 conference in Colorado in October of this year. (more…)

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So the legal trials and travails begin.  Here is the first announcement:

LONDON, Ontario–(BUSINESS WIRE)–Siskinds LLP today announced the commencement of an investor class action against Imperial Metals Corporation (“Imperial”) (TSX:III) and certain of its directors, officers and related parties. The action relates to the circumstances surrounding the failure of the tailings facilities at Imperial’s Mount Polley gold and copper mine near Likely, British Columbia on August 4, 2014.  The action is brought to recover losses suffered by persons who acquired common shares or notes of Imperial between August 15, 2011 and August 4, 2014.

Siskinds website is at this link.  Appears they specialize in class action law suites, and to judge they are often successful.  Here is how they describe themselves:

The Siskinds class action team is comprised of a group of seasoned and talented litigators with a substantial record of success for their clients, both plaintiffs and defendants.  Siskinds has acted as counsel in more than 100 class actions. These include class actions involving breast implants, vanishing premium insurance products, price fixing conspiracies, defective drugs, employment and pension claims, environmental actions, and securities litigation.

If share prices for Imperial Metals have fallen forty or more percent, and they could fall more as the implications of the failure become more stark, then there certainly was a lot of money lost by investors.

Siskinds is casting the net wide.  They are intending to sue directors, officers, and related parties.  Could they sue the provincial regulators?  Certainly they will include the engineering companies involved.

Will they have to prove negligence or merely involvement?   Do they have to prove that the actions of one or more of the parties involved were the cause of the failure?  Or is it enough to establish loss of share value?

Thus we have another item to add to the list of the cost of “cleanup.”

 

 

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The Vancouver Sun reports as follows about the Mt Polley tailings failure:

Likely resident Gerald MacBurney worked at Mount Polley for seven years, the last two he says as a foreman directing work on the tailings dam.

He says AMEC instructed the company to bring in five million tonnes of rock to shore up the outside of the dam in order to handle the increased amount of water in the tailings pond.

He said the company never carried through, perhaps only bringing in one million tonnes of rock.

That’s because they didn’t want to take their large equipment — big haul trucks that can carry as much as 120 to 200 tonnes — away from delivering ore to the mill, according to MacBurney.

Global BC reports MacBurney as saying:

“They needed to put in five million tonnes [of rock] around the dam, because they added, once they went to a bigger mine life, they added five times the amount of water,” adds MacBurney. “That dam was never designed to hold five times that amount of water.”

“Five million tonnes, well we got maybe a couple hundred thousand. And that’s it, in two years. I’d had enough.”

“They carried on going up instead of wider and doing the proper way of doing it,” says MacBurney.

 

Constructing a buttress of rock around the perimeter of a tailings facility embankment is not new or for that matter uncommon.  If the embankment slopes are steep and going higher than original planned, it is reasonable to construct a buttress around the toe of the dam. If water is seeping out of the impoundment and emerging as flow at the toe of the embankment, you first place a filter and then the mass of the buttress.

A decision to construct a filter and buttress at the toe of a tailings facility embankment is not taken lightly.  It is inevitably expensive to build.  But where there are valid concerns for the stability and integrity of the perimeter embankment, that is what is done.

If, as MacBurney says, a decision to stabilize the embankments was made, clearly somebody had concerns about the stability of the facility.  There must somewhere be a letter, report, or drawing showing what had to be done and explaining why it had to be done.  Such a document would surely have been provided to the regulators–for so significant a change from the original design would have required their concurrence.

And when timely construction of the buttress was not happening, surely somebody besides MacBurney, must have been concerned.  One would have expected the regulators to at the least have written to the company urging completion of the stabilization works.

I am not convinced that a buttress would have prevented the failure.   I suspect the upstream circular arc failure zone that is so apparent in the videos I have seen indicates high pore water pressures in the upstream part of the embankment–high enough pressures to have cause the failure.  Such a failure would not have been precluded by a buttress.

But if the two embankment that came together at the corner where failure occurred were moving apart, then the buttress may have indeed limited the movement.  Here is a picture of a recent failure in Hungary where the two perpendicular embankment both moved outwards and away from each other.  Maybe this is part of the Mt Polley story.

This mystery of the missing buttress could easily be cleared up if we had ready access to the reports.  Or if all such document were made public.

 

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The official statements are now beginning to appear re Mt Polley.  Here are two.  First from the Mining Association of Canada. (more…)

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Standard accident theory tells us that an accident occurs when many small incidents or omissions line up.  It is like a pile of Swiss cheese with hole in it: inevitably a pile of cheese with hole in it will result where holes line up and you could poke a knitting needle through the holes without penetrating the cheese. This theory explains what happened at Mt Polley.  Many tiny acts and omissions lined up—and we see now the results. (more…)

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In one of the many article I read on the Mt Polley tailings failure was an estimate of what it will cost to get the mine going again.   A figure of $50 million was quoted as the cost to pick up all the tailings and return them to the tailings facility.  I imagine that figure is based on five million cubic meters of tailings at about $10 a cubic meter to pick up.  Here is why I suspect the figure is grossly low. (more…)

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Today we have read all we can find on the failure of the Mt Polley tailings facility.  It is all distressing.  And mostly misleading.  Here are a few clear thoughts on the topic. (more…)

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