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.
I cannot possible do his talk justice in a blog posting. I will try here to capture a few more of his insights, but be assured they are deeper and more profound than anything I can write.
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.
I wonder if the mining industry is not going to have to face the fact that the only walk-away strategy is to fully close the impoundment in accordance with the principles we applied on UMTRA and beyond, and then finance a public institute that will take over perpetual observation and responsibility for action to keep the facility sound—or at least in balance with the receiving environment.
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.
That is why I invest only in mines in dry places and in places where they practice tailings dry stacking. Maybe only the power of the shareholder acting in concert with the law-maker can take us into a future of responsible, sustainable mining.
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.
Lot to think about from this conference.