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.
It is always a very sad day when a major tailings facility failure occurs. As one commenter noted to me: “Whatever the facts, the failure casts a poor light on the industry, and makes all of our jobs more difficult in the future.”
Today we write about the failure of the Mt Polley tailings facility right here in British Columbia. I write only on the basis of the information readily available on the web. I have no other source of knowledge of this facility.
My first impression is that this is in a direct line of failures from Bafokeng, through Merriespruit, to now. Nothing has changed, this failure looks just like the failed Bafokeng dam looked when I went out to see it the week after it failed way back in the earlier 1970s.
We still cannot agree if the cause of the Bafokeng failure was overtopping of the crest of the perimeter embankment by too much water in the dam, piping of water through a sandy layer in the embankment, or slope instability via sliding of soft foundation clays.