By Jack Caldwell - Mining Engineer - Robertson GeoConsultants

The Second International Oil Sands Tailings conference was held in Edmonton, Alberta, December 5-8, 2010. Here is my summary of two days of listening to presentations.

Two years ago the focus was on consolidated tailings. This year the focus was on polymer amendment of Mature Fine Tailings (MFT) which is the fine clay tailings that never settles and never gains strength. Unless that is you do something to it. The impetus to do something is the regulation called Directive 74 that demands a strength of 5kPa one year after deposition.

The most obvious thing to do is to add a polymer to the MFT. As presented in many papers this year, most polymers will work. The trick is in mixing the polymer into the MFT. Do it wrong and nothing happens. Do it right and you get 5 kPa material a few days later. So we grieve for those poor researchers pursuing the holy grail of the perfect polymer who forget to concentrate on mixing technique. They are doomed to failure and frustration. Unless of course they get involved in the massive information transfer promised by the reported collaboration between oil sands operators to share information on ways to get five kilopascals—this industry sharing of information is reported on in today’s Globe and Mail.

Then we have a second focus on naphtha in the tailings. This is a naturally occurring constituent of the deposit, which tends to accumulate in the tailings, and which, if allowed to escape, could impact water quality. Dealing with this is the topic of much research but no final answers at present.

A third focus is Directive 74 itself. I have previously written that this is the most unfortunate regulation ever imposed on a mining industry anywhere in the world. It is the product of ignorance on the part of the regulators, misinterpretation of a badly written technical paper, and a failure by the industry to protest before it was too late. Now it is in place. Today we heard a reasoned argument why it should be scrapped. Nothing will happen. The requirement to achieve an un-measurable strength will remain in place and rational humans will dance around it and pervert the law to make life liveable.

Isolated papers stand out. Jamie Sharp presented the keynote address on the use of Cone Penetration Testing (CPT) to establish the in situ properties of oil sands tailings. Jamie and ConeTec have made substantial contributions to our understanding of the nature and properties of oil sand tailings. The supreme irony is that he can measure 5 kPa easily, but oil sands tailings of that strength are utterly unable to support people or equipment needed to advance equipment to measure such strengths.

Fact is you need 15 to 25 kPa before I can walk on oil sands tailings. The 5 kPa of Directive 74 is a fiction of a misinformed belief that you could walk on 5 kPa tailings.

Of fun interest was the paper on remote measurement of oil sand tailings properties. The authors propose remote controlled vehicles running over soft (5 kPa) tailings to measure the low strength. Just goes to show how ridiculous regulations give rise to asinine actions in the hope of finding solutions to non-problems.

Another fun paper dealt with capping soft tailings by dumping sand from a barge floating on the pond over the soft tailings. This has been done in other parts of the world. I once was involved with a project to place a sand cover over PCB contaminated sediments off the coast of southern California. I have heard talk of doing this at one of the many ponds that is nearing closure in the oil sands industry. It could work, but will require prudent engineering and patience.

If you want to read the papers you will have to contact Sally Petaske at the University of Alberta, or await posting in about two weeks time of the PowerPoint presentations on their website.

PS. If the reported industry cooperation goes ahead, then we may conclude that Directive 74 has achieved an unintended outcome: namely industry cooperation. Pity that the industry did not cooperate to kill the regulation. But now maybe they will cooperate to common good.