Mt Polley Implications for World-Wide Mining
February 7, 2015 by Jack Caldwell
The blogger muse prompted by opera & brandy demands release of mental pressure. Thus a second posting on Mt Polley in one day.
This afternoon, I was asked what the implications of Mt Polley were to mining world-wide. Some of the answers, unpremeditated, I gave.
Every mine will have to have an Independent Review of their tailings facility. And if they do not, only foolhardy investors will invest.
Every new mine will have to do filter-pressed tailings or fully justify why not. There are many mines in operation and planned that do it.
Existing tailings facilities with wet, fluid tailings will have to install wick drains immediately upstream of the embankments in order to dewater the tailings.
No more water storage on the tailings facility. Thus big water treatment plants.
Mines with acid generating tailings may continue with water covers. But only if they have a second, downstream embankment and empty reservoir to contain tailings in the event of a breach of the main dam. Just like so many California water dams. And just like Ekati in the Northwest Territories. No excuses, there is already a mine that does it, and they do not have acid generating tailings.
Backfill underground mine workings with tailings, and put only the least possible volume of tailings above ground.
Have an independent consultant, not part of the review panel, prepare a quarterly report on the status of the tailings facility. And make this report public and reassure investors. They have done this in South Africa since the failure of Merriespruit, and they have had no failures since.
Not every ore body will become a mine. Only those of rich potential and sufficient income to do the above will be developed. Thus mines in dry places like Nevada and the Atacama are good places for new mines. Wet places like British Columbia will have to, like Greens Creek, Alaska, go filter pressed or double embankments.
Andy Robertson speculates that we have reached a turning point in the size and height of new tailings dams. There is one planned to go more than 300 meters. Maybe this will be the highest we will go. For the risk and consequences of failure are proportional to dam height.
All this will cost money for existing mines. All this may stop development of many a new ore body. The technology of tailings management will change. And thus the mines developed and their economics have changed.
For the mining industry will not survive four tailings failures a year indefinitively. Fun as it has been to write a paper each year for the Tailings and Mine Waste conference on the four tailings failures in 2012, 2013, and 2014, I cannot go on. The four a year I have written about is but the tip of the iceberg. Each year there were more failures not made public. There were many more serious near-failures that were prevented only by heroes.
The Mt Polley reviewers say that if we do not change things there will be two more tailings failures in BC in the next decade. This number is probably correct if you consider that we have four in each of 2012, 2013, and 2014. Thus another 40 in the next ten years. If you postulate that worldwide there are twenty areas of mining with a comparable number of tailings facilities to BC, you get two failures per decade per mining area. Anyway you calculate it, four a year, two a decade by area is the way it will be, unless there is drastic & dramatic change.
Mt Polley Warrants and Cherry-Picking
February 4, 2015 by Jack Caldwell
As we emerged from the elevators this evening, we were confronted by a phalanx of reporters and photographers. Luckily they did not recognize a notorious blogger or my companion, a famous tailings engineer. They did not take our photos. They were waiting for officials of Imperial Metals whose offices are in the same building as ours.
We knew that the search warrant had been acted on and the computers of Imperial Metals had been seized–see this report. Part of the report says;
The B.C. Conservation Service executed search warrants at the Mount Polley mine and the Vancouver offices of its owner Imperial Metals Tuesday night, in relation to the spill of 25 million cubic metres of waste from the mine’s tailings pond last August
Insp. Chris Doyle with the conservation service said the search warrants were issued to support a joint investigation by the B.C. Conservation Service, the RCMP, Environment Canada and Fisheries and Oceans Canada.
Point is that all the panel’s recommendations must be implemented as a whole. I am told the mining industry is screaming blue murder about no water on the tailings facility, filter-pressed tailings, comprehensive probabilistic water balances, factors of operating safety greater than 1.5, and so on. The mining industry must be lobbying the politicians to limit future changes to an Independent Review Panel
Not enough; on the basis of a story I heard today about an Independent Review Panel that was repeatedly ignored with the result that millions were spent on inappropriate site cleanup works. Now the Federal government is asking how taxpayer dollars were wasted as a provincial government and American consultants managed to suppress the Independent Review Panel’s findings. A fascinating story that will come out eventually we hope. But for now it proves that Independent Review Panels are powerless in the face of intransigent project folk and hence are totally insufficient to implement the Mt Polly panel’s recommendations.
Minister Bennett must lead and announce that all the panel’s findings are now required practice by the BC mining industry. Anything less and we will have at least two more Mt Polleys in the next decade. And the mining industry will not survive that.
PS. Today I also learnt that in Brazil, the standard practice is to use a factor of safety of 1.3 for operating tailings facilities. Recall that last year the failure of a tailings facility in Brazil killed three people. Being a Latin country, no official report is planned, so we probably never know more. But now we have two instances where a factor of safety is in fact a probability of failure of certainty.