I THINK MINING

At the First International Oil Sands Tailings Conference held in early December 2008 in Edmonton, Richard Houlihan of the Alberta Energy Resource Conservation Board (ERCB) talked about proposed new ERCB regulations for oil sands tailings disposal.  Let me in this long posting comment and offer my perspective.  Adult content warning: the following may offend.

The technical paper that accompanies Houlihan’s talk says this about the performance criteria the ERCB will demand be met (I quote it all as the implications are many millions of dollars; but I confess that in spite of my LLB I cannot make head or tail of this prose):

The performance criterion for fluid tailings reduction is based on fines captured in the Dedicated Disposal Areas (DDAs). Fines are defined as mineral solids with particle sizes equal to or less than 44 micrometers. The criterion establishes a minimum mass of dry fines in the oil sands feed expressed as a percentage of total fines in feed that must report to the DDAs. This requirement applies to a one-year period between surveys and phased as follows:
>  20 percent from July 1, 2010 to June 30, 2011
>  30 percent from July 1, 2012 to June 30, 2012
>  50 percent from July 1, 2012 to June 30, 2013 and annually thereafter. The above requirements are for fines deposited in DDAs. The fines captured in DDAs must be in addition to the fines captured currently in hydraulically placed dikes and beaches.

DDAs must be formed in a manner that ensures trafficable deposits. The performance criteria are based on the strength of the deposit. The following criteria must be achieved annually:
>  Minimum undrained shear strength of 5 kilopascals (kPa) for the material deposited in the previous year.
>  Removal or remediation of material deposited in the previous year that does not meet the 5 kPa requirement
>  Deposit ready for reclamation within five years after active deposition has ceased. The deposit will have the strength, stability, and structure necessary to establish a trafficable surface. The surface must have minimum undrained shear strength of 10 kPa.

In summary, I suppose this says that you must entrain up to fifty percent of the clays in the sands and the resultant mass must get stronger and stronger as the days pass.

New regulations that have a profound impact on a major industry are inevitably controversial. But there appears to be no controversy arising from the oil sands companies. In the Q&A session, oil sands industry representatives generally complimented Houlihan for a thoughtful and reflective presentation and said they believed they could comply with the regulations. That is good.  Or is it?

Some industry watchers have noted that the proposed new regulations have been long in coming, and may not be stringent enough. But that is a standard refrain from the negative-nabobs, so we need not delay to consider their concerns.

Houlihan rightly recognized that there is a long history of oil sands tailings deposition and not all of it may have been good. But he emphasized that the task ahead of us it to make things better, not ruminate too much on the past.

In spite of Houlihan’s sober and thoughtful presentation and the positive industry response, I confess to a slight unease about the proposed regulations. Let me explain why.

A good law, rule, or regulation (I shall use the word regulation only in the remainder of this posting) is easy to understand and enforce. Even better is a regulation that it does not have to be enforced: people simply act in accordance with the spirit and letter of the regulation because it is so obviously the sensible thing to do.

A good regulation sets noble and achievable goals and leaves it to the person complying with the regulation to find the best way to achieve the goals inherent in the regulation.

Regulations may be prescriptive or performance-based. For example, a prescriptive regulation tells you to put three-feet of clay with a hydraulic conductivity of less than 10-6 cm/sec as the liner beneath your impoundment. By comparison, a performance-based regulation says: operate the impoundment so that is does not affect water quality—you prove to us that you are protecting groundwater quality.

Prescriptive regulations inevitably fail to achieve the desired outcome. Prescriptive regulations fail because they stifle human ingenuity and technical innovation. It’s like the failure of five-year plans to stimulate a communist economy.

At the worst a prescriptive regulation eliminates innovation and stops progress leading to a net loss for stakeholders and the environment.

My favourite example of a good goal-base regulation (actually a law of the United States government) is the one that governed the Uranium Mill Tailings Remediation (UMTRA) Project. It was pretty simple. It stated: close those 24 uranium mill tailings piles so that they are stable for 1,000 years to the extent reasonably achievable, and at any rate for 200 years.

On the basis of that simple directive, we advanced technology, improved engineering practice, remediated the sites, and got almost everybody to support what we did.

A good example of a bad regulation is the one foisted on the landfill industry many years ago. The regulation mandated a liner of clay with a specified thickness and permeability. In places where there was no clay, this caused great confusion. In practice, after a lot of to-and-fro, the industry was allowed to use geosynthetics including geomembranes, geosynthetic-clay-layers, and other innovative, technically sound, and cost-effect components. And there was far better groundwater as a result.

Now let us look at just one part of the proposed ERCB regulation for oil sands tailings. They say that within one year of placement the tailings should have a strength greater than 5 kPa and ultimately the strength should be greater than 10 kPa. And if the strength falls below those limits you will scoop them up, take them back to the plant, and rework them.

Let us leave aside the terminal ambiguity of how you measure the strength (I doubt a geotechnical engineer was involved in setting this vague requirement.) Fact is the five and ten kilopascal requirements are lifted from a technical paper by Jakubick, A., McKenna, G., and Robertson, A. (2003): Stabilisation of Tailings Deposits: International Experience. Proceedings of Mining and the Environment III, Sudbury, Ontario, Canada, 25-28 May, 2003.

Read this paper and you quickly see that it has nothing to do with oil sands tailings. It is all about uranium mill tailings stabilization in East Germany. And sadly it is based on out-of-date technology, now superseded by the vastly more powerful computer code FLAC. This is an egregious example of inappropriate engineering and regulation.

I admit that the underlying objective of the proposed ERCB regulations is noble: do not leave behind an oil sands tailings impoundment that consists of a well-engineered earth dike holding back fluid tailings. Presumably the regulators who wrote this proposed regulation want to avoid dike failure and flow of the impounded fluid-like tailings down the Athabasca River any time in the perpetual future.
Which make you wonder why they did not simply say so? They could have written the new regulation thus:

Design, build, operate, and close oil sands tailings impoundments so that they do not breach and the contents do not flow out for at least 10,000 years to the extent reasonably achievable and at any rate for 2,000 years.

There are many ways to achieve this and hence protect human health and the environment. Although I admit, the industry would probably not fall in line behind the regulators at the thought of providing long-term impoundment integrity. Much easier to support 5 and 10, ambiguous as they are.

On a small scale, tailings with a strength of five to ten kilopascals have been placed successfully for over twenty years at the Greens Creek mine on Admiralty Island in Alaska. They simply filter press the tailings, add a bit of cement, and place the result in a solid pile. In effect this is what the ERCB wants and is demanding. Witness the many presentations at the conference on ways to press, spin, swirl, and chemically amend the mud-like tailings to make the awesome floc. I propose a field trip to Juneau and Hawk Inlet.

With all due respect to the scientists and engineers who are working so hard and presenting papers at the conference, it is going to take many dollars and much energy to achieve a comparable result in Fort McMurray.

A solid with an ill-defined strength may still seep, leak, liquefy, flow, or pollute. A pile of weak solids is still vulnerable to geomorphic forces. It is still liable to precipitation infiltration, throughflow, and exfiltration to the groundwater and surface waters.

As Gord McKenna said in his presentation to the conference attendees, the oil sands industry is light-years ahead of the regulators in seeking to achieve cost-effective, practical, and safe closure of the oil sands tailings impoundments. And the industry will remain ahead of the regulators if these proposed regulations are any indication. That is probably why they are so kind in commenting on them. 

But, the narrow focus of the proposed ERC regulations ignore issues the industry is facing and stakeholders are interested in; these issues include geomorphic stability, infiltration, exfiltration, constituent migration, landscaping, and support of vegetation.

It is sad to think of the energy and effort that will go into fighting about mud strength, fighting about CPT strength versus shear vane strength, total versus effective strength, pore pressure buildup and dissipation, strain rates and the normal distribution curve versus beta tail of field data. As a lawyer, I would challenge the proposed regulations on the basis that they are terminally ambiguous and un-interpretable.

That said, I recognize that most likely somewhere there is a young scientist, a bright engineer, an innovative manufacturer, or an avid supplier of chemicals with the solution to turning mud into rock up their sleeve. We must grant that these regulations are spurring vast quantities of research by eager manufacturers to come up with a better cyclone, a more effective thickener, or a floc-producing polymer. But if I am wrong and the solution to turning mud into rock is not just over the horizon, then these regulations are about to impose impossible costs and the death sentence on many an oil sand miner. As one of the regulators I spoke to during the conference said: “If they cannot do what we demand, or cannot afford it, then they had better not mine.”

These regulations ignore the benefits of in-pit disposal as compared to above-grade impoundment. The regulations ignore the potentials of a water cover, the opportunities inherent in geosynthetics, and the genius of engineered dike designers.

There is another aspect of the regulations that demands comment. There is the strange requirement that a specified percentage of the clay-sized tailings be entrained in the sands or awesome flocs. The presentation by Houlihan left me confused about just how much clay entrainment is required. In the Q&A period he equivocated on the issue. I would have thought it better to get the clay out of the sand rather than legislate to foul up the sand with the clay. Maybe I just have it all inside-out and backwards. And the oil sands industry sees this topsy-turvy regulation as a glorious opportunity to drive a Moxie through the holes in the logic and prose.

I admit to a certain absence of knowledge about oil sands tailings. I have not devoted a career to them. I am not privy to the insider lingo and quiet interactions that occur in cold climates. So I say at the outset sorry to any I may offend with these remarks. I am honoured to be in a position to comment and assure you my intention is to get folk thinking so that a better regulation is imposed. I aim for a simple, clear, regulation that is easy to follow, implement, and which truly leads to long-term protection of human health and the environment. So if you must respond and criticize me, do it only on the basis that the current regulations will lead to geomorphically stable, unleaking, vegetated landscape forms that will never flow down the Athabasca River. Whereas my approach would not achieve as fine a result.