Here is an issue that is fascinating and the information is a trifle tedious to find.

The topic is a call from MSHA for comments on ways to make mine tailings dams safer.

I urge you to comment if you can. My first comment is that you need but two things to make safe tailings dams:

  1. A Professional Engineer of Record (PE) who personally inspects the dam at least twice a year and who has trusted subordinates record and report on conditions every month.
  2. A Peer Review Board that meets at least twice a year to review conditions. The peer reviewers must be totally independent of the professional engineer and his firm and must report to the highest possible level of mine management. There should be at least three peer reviewers, all from different organizations and of varying, but relevant disciplines.

My second comment is that no tailings facility is safe unless it is like those Cahokia Mounds. These are 1,000-year old soil mounds just east of St. Louis, Missouri.

The only modern tailings disposal facility I know of that meets my criterion for stability and safety is the Greens Creek, Alaska tailings disposal facility.

The fact is that only way to achieve safe tailings disposal is to dry, filter press, or amend the tailings to become a solid as Suncor is doing in Alberta. As long as we insist in discharging liquid tailings, we risk failure. This, I believe, is true regardless of the robustness of the embankment dam that may be constructed to retain the liquid tailings. For earth dams or embankments fail.The record of such failures is long. If the retained slimes are fluid, they will, and have, flowed out and caused incredible environmental impact and death.

Maybe the way we did it on the UMTRA Project is another example, another way to ensure safe tailings dams. At least, UMTRA is an example of the best way to close a tailings impoundment. It will take a genius to incorporate its principles into the design and operation of a new tailings facility.

I strongly recommend against more volumes of guidelines. There are enough of those already and they add nothing. They are mostly the product of consultants who have never managed a tailings facility, and they are generally no more than out-of-date checklists. Avoid them completely, whatever their proponents may claim. I personally cringe when I read them or hear them cited as examples of good tailings practice.

Maybe at the Conference in Vail in October on Tailings & Mine Waste we should spend a whole session talking about this. We have a paper in the conference on this very topic which pretty much says what I say above. In our paper we reject all the fallacious theories of why slimes dams fail. It all boils down to the failure to have responsible PEs, very frequent intelligent inspections, and independent peer reviewers. Just think how many taxpayer dollars could be saved, if our paper were read and our recommendations implemented

The paper will appear in the conference proceedings, but if you want a copy now, e-mail me at jcaldwell@infomine.com.

To read MSHA’s entire statement, please click here.