Oil sands tailings – what’s left after the raw sand has been processed to extract the useful bitumen – has always been a complex challenge for the industry.
Oil sands mine tailings are a mixture of water, clay, sand and residual bitumen. They can’t be easily changed into anything useful, nor can they be released into nature.
The culprit is a component of the mix known in the trade as fine tailings. Made up of fine clay particles suspended in water, fine tailings are a goopy, fluid material that doesn’t quickly firm up on its own. (As you may recall, industry drew the ire of environmental groups a few years ago when it used the term “yogurt” to describe fine tailings’ consistency.)
The traditional solution has been to store tailings in specially-built ponds. Operators have needed more and larger ponds over the years as production increased. As a result, Alberta contains some 170 square kilometers of tailings ponds.
This traditional method of managing tailings, of course, is no longer acceptable. In 2009, the Alberta government drew its line in the sand, mandating operators to reduce tailings and provide target dates for closure and reclamation of ponds. It also set deadlines for companies to process fluid tailings at the same rate they produce them, effectively eliminating the need to build new ponds.
While setting deadlines is one thing, cracking the tailings challenge technologically is another.
Up until a few years ago, each company has been tackling the tailings conundrum largely in a go-it-alone fashion. Some good results were achieved, including development of Suncor’s TRO process. Recognizing many hands make lighter work, seven leading operators, Suncor among them, agreed in 2010 to pool their know-how and research funds into a single collaborative body called the Oil Sands Tailing Consortium (OSTC).
OSTC’s membership brought together decades of experience and investment in tailings management. Members collectively invested over $400 million into tailings research.
Tailings Roadmap and Action Plan
Recently the OSTC and Alberta Innovates, which advises the Alberta government on research, technological development and science policy, published a landmark report to consider existing tailings management efforts. While noting that there was no silver bullet, the Tailings Roadmap and Action Plan highlighted the wide range of technologies being pursued, with names guaranteed to quicken the pulse of any engineer. In-line thickening with accelerated dewatering. Retort-based extraction. Parallel high/low fines suite.
Like a good GPS device, the report offered operators not one but several options for getting to the same destination of better tailings management.
This new tailings knowledge is great news for our industry and an example of what can be achieved when organizations collaborate. This expertise should continue to ramp up as tailings is a key focus of Canada’s Oil Sands Innovation Alliance, the 12-producer entity formed to drive environmental performance improvements in the industry.
Now if somebody in public relations could only come up with a better term to describe fine tailings.