On thermosyphons

March 5, 2014

I’m taking a MOOC (Massive Open Online Course) from science studies guru Bruno Latour called “Scientific


Humanities.” As part of an assignment, I wrote about the idea of thermosyphons  (including those being deployed at Giant Mine) as a “sociotechnical project.” I thought I’d share the post here:

The Thermosyphon: cold technology, hot issue.

As Prof. Latour tells us, “any object is only a temporary stage extracted from a series of transformations the initial project had to undergo to navigate a range of opponents and supporters…” (paraphrasing a bit here). So it seems to me (pace Lepawsky and Mather), that we need to start *in the middle* and avoid the implicit stability and linearity of the association/substitution diagram (even with its detours), while preserving the essential traceability of these relations and moves.

So, come with me to Northern Canada, to an abandoned mine just outside of Yellowknife, the capital of the Northwest Territories, where we encounter these strange, ranked, tube-like figures on the landscape, clearly not part of the old mine. They are **thermosyphons**, and here in Subarctic Canada (perhaps paradoxically), they are intended to keep the ground *frozen*, so as to protect people and nature. ![Thermosyhpons at Giant Mine][1]

Thermosyphons are at once a novel and mundane technology–[simple science][2], according to one news report–now at the centre of an intense controversy about how to properly remediate an abandoned mine and protect the local environment and communities from poisons buried in the mine. But to understand why this is controversial, we need to trace this project back to the point at which it moved from mundane, if somewhat clever technological object (no more fascinating, in some ways, than a straw), and forward to when it moved the centre of a dramatic debate about toxicity, climate change, and the future of human existence on earth.

Like so many ‘inventions,’ thermosyphons are at once simple and ingenious. They are a two-phase convection device that consists of an enclosed tube and a gas/fluid medium (carbon dioxide) that allows heat to be transmitted from one end of the tube to the other, with no artificial power or refrigeration. Their use in cold regions dates to the 1960s, but they really took off in the 1970s as they began to be used to solve problems of construction and ground stabilization in permafrost environments.

See, when people disturb the surface (vegetated or otherwise) of permafrost (areas of ground permanently frozen below a certain level, even in summer), that permafrost ground becomes unstable, which can lead to slumping, heaving, etc. In addition, the surface material in many northern regions isn’t really great construction material for dams and mine tailings facilities–it’s porous, and tends to leak and slump. So in the 1970s, engineers began experimenting with “frozen core” dams, using the natural cold of the environment to provide a solid barrier against water. Applying thermosyphons, they could ensure these dams would remain stable, even in the warmer summer months, by keeping the frozen core cold through the air/gas exchange process.

The same issues apply to the built environment: roads, railways, pipelines, buildings, etc., all tend to degrade permafrost; one way to keep the ground below these installations solid is to install themosyphons, which keep the ground nicely cold year-round. This technology is now widely used in circumpolar regions, including in Yellowknife, where the parking lot of the territorial legislature sports thermosyphons to keep the pavement (relatively) secure. It’s also used for hockey rinks. Very Canadian.

Behind (well, not far behind) this technology is a body of knowledge and suite of actors familiar to many northerners: the U.S. Army Corps of Engineers, for one, but also many mining and civil engineers, consultants, construction companies, town planners, and (likely) insurers, all with a common interest in keeping the ground cold, even as they transform it. Capital and entrepreneurs, too, play their role: as a recent [Wall Street Journal][3] article noted, the Alaska company Arctic Foundations now supplies the circumpolar world with thermosyphon technology. Indeed, as the article notes, the company and its technology have an ever-more important role to play as northern regions face a new challenge to their comfortably (?) familiar cold environment: climate change is rapidly altering permafrost regimes in the north and presenting new engineering challenges to industry and infrastructure in the region. Stay tuned: like the deus (diabolus?) ex machina, Klima will return in dramatic fashion to the thermosyphon story.

Thermosyphons to the rescue

The thermosyphon comes centre stage in this story as the proposed solution to the immense and frightening techno-political problem of how to deal with the toxic legacy of a bankrupt and abandoned gold mine in Yellowknife. The Canadian government, inheritors of this dubious legacy, conducted a series of engineering studies in the mid 2000s to find the best solution to the disposal–or securing–of the 237,000 tonnes of toxic arsenic trioxide left behind by mining that the local community feared would ultimately poison the environment. As the government’s [Giant Mine Remediation Project][4] website is at pains to point out, in seeking a solution, federal authorities sought the advice of expert [technical advisor][5] and an [Independent Review Panel][6], consisting of nine recognized experts in the fields of geotechnology, mining, mineral processing and environmental engineering, toxicology, hydrogeology, risk assessment, and public health. The government ultimately proposed the “frozen block method,” essentially proposing to freeze the arsenic in place underground (it’s not frozen now; permafrost has been disturbed) and to maintain that frozen state using thermosyphons “in perpetuity.”

Here’s where those thermosyphons start to look, for many in Yellowknife, less like friendly symbols of stable ground and more like harbingers of an uncertain and scary future. During the environmental assessment process for the proposal, some experts and many members of the general public (including local indigenous communities) challenged the suitability of thermosyphons as a guarantor of future frigidity, citing the need for ongoing maintenance and occasional replacement. Thermosyphons, with their simplicity and lack of need for external power sources, were touted by the government and technical supporters as key to their suitability for the “long term” solution to the problem; but it is the very question of *how long this term is* that opponents seized upon in their criticism. What about seismic events, they asked? What about climate change, occurring more rapidly in Arctic regions than anywhere else on the planet? Could this friendly technology handle the load? Government experts answered yes, but the criticisms registered strongly with the regulators reviewing the project.

Perhaps even more pointedly, some raised the question of the maintenance of this site, “in perpetuity.” How is it possible to ensure the stability and effectiveness of this technology into a long-distant future, much less beyond the political whims of elections cycles and budget priorities? How can we ensure that future generations understand why these skinny sentinels stand at this site, and the nature of the danger that lies beneath, poison to all life?

As a sociotechnical project, the thermosyphons at Giant Mine ramify like few others I’ve encountered (though no doubt, like many others I haven’t given a thought to). The debate over their use at Giant Mine is ongoing, and I’ll be following their transformations in my research, as I try to understand some of the questions they raise about extraction, justice, care, and (yes) technology.

[1]: http://www.toxiclegacies.com/wordpress/wp-content/uploads/Pine-Point-009.jpg

[2]: http://www.ktuu.com/news/news/simple-science-keeps-alaskas-permafrost-frozen/24445196

[3]: http://online.wsj.com/news/articles/SB10001424052748704576204574531373037560240

[4]: http://www.aadnc-aandc.gc.ca/eng/1100100027395/1100100027396

[5]: http://www.aadnc-aandc.gc.ca/eng/1100100027449/1100100027450

[6]: http://www.aadnc-aandc.gc.ca/eng/1100100027443/1100100027444