Jack Caldwell, P.E. has a B.Sc. in Civil Engineering, an M.Sc. (Eng.) in Geotechnical Engineering and a post-graduate law degree. He has over 35 years engineering experience on mining, civil, geotechnical and site remediation projects. He has worked on numerous projects throughout southern Africa, Europe, Canada and the United States.
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.
The videos show that the tailings and water are still pouring out of the failed facility. Problem number one is how do you stop this flow. I do not know how I would stop the flow and nobody seems concerned to stop the flow. But more tailings and contaminated water are escaping as we write. If it rains, even more will be washed out. Demand number one is an answer as to how continued tailings flow will be stopped.
I can accept that the water and all it nasty constituents will be diluted by the rivers and lakes into which the water is flowing. But what of the solids? They are in the river, on the banks, and now in the lake. Will it ever be possible to clean this up, or will these tailings have to be allowed to wash by rain into the lake to join the bottom sediments? Maybe we need to build an emergency dam up-river of the lake to catch the solids.
Imperial Metals is saying the area affected is small by comparison with the area of the tailings facility. This is true, but irrelevant. Until they stop outflow, the threat of all the tailings to the environment remains.
Nobody but me is prepared to say why it failed. I suspect it failed because there was too much water in the dam, the corner gave way, an upstream slide occurred, and the disaster ensued. They are saying nobody could have anticipated this. Rubbish. It was entirely predictable given the facts. It is just nobody had the courage to speak.
The sad thing is that if indeed the dam was being operated in accordance with plans and permits, the consultants are to blame. The same guys who were designing the Pebble Mine tailings facilities and telling us the facility would be OK forever.
The shares fell a mere 42 percent. Fact is the company will go under and the shares are probably worthless. The only question is will the insurers of the mine and the consultants be able to pay or will the taxpayer foot the bill. My guess is the latter.
The fact is that this event is a seminal event in mining history. . Never again will we open a mine where the tailings are above salmon grounds. Never again will we believe consultants, mining executives, or regulators. Never again will we build by the centerline method. Never again will we open a mine that does not use filtered tailings. So much for conferences on paste tailings.
Forgive me if these opinions are too strong for you. But in the midst of all the feel-good pronouncements by company officials and government hacks, I think a few honest mining thoughts are not out of place.
For the original source of this column, click here: http://ithinkmining.com/2014/08/06/mt-polley-tailings-failure-lies-versus-the-truth/