Tar sands are composed of sands (ranging from loose to
nearly-rock) mixed with clay and saturated with bitumen. Bitumen, or
colloquially, tar, is a very dense, viscuous form of petroleum. People and
bitumen go way back – all the way back. Since homo sapiens arrived on the
global scene, bitumen was used for building construction, waterproofing boats,
and more. Even before that, Neanderthals seemed to have used it as a component
in their stone tools. Several ancient civilizations used bitumen as a gluing
and waterproofing agent for various applications. This should also give you
some sense of what a schlep it is to turn this mucky, sticky stuff into smooth
liquid fuel.
But before we discuss how we get the oil out of the sand,
how did it get there in the first place?
That’s a long story – billions of years long, in fact – but
the short version is that when the Pacific Plate crushed up over the North
American Plate, forming the Canadian Rockies, the sedimentary rocks composing a
great deal of the Alberta plains were buried below. The increased pressure from
the overlying mountains and the increased heat from (relative) proximity to the
earth’s mantle transformed some of the organic material (specifically the
kerogen) in those rocks into light oil and natural gas. The configuration of
the regional geology was such that the oil and gas was seeped out and up toward
the northeast, and as it reached shallower depths, it was discovered by
microrganisms with strange appetites, who we can imagine had a great time as
they ate it up and sent it back out as the sticky, icky bitumen we know today,
in a process properly described as microbial biodegradation.
Tar sands can be found in several countries around the
globe, but there are especially large reserves in Canada, Russia, and
Kazakhstan. Of particular significance to the United States are the Alberta tar
sands, which lie in the Canadian Boreal forest and contain about two trillion
barrels of oil. The Athabasca oil sands near Fort McMurray, Alberta are the
largest deposit in Canada. It conveniently reaches right up to the surface
north of Fort McMurray, but the rest is buried about a thousand feet below
ground. Thus only twenty percent of the recoverable oil in that deposit can be
recovered by surface mining, which. The rest requires in-situ mining
techniques, most commonly Steam Assisted Gravity Drainage (SAGD) in which two
horizontal wells are drilled into the sands, one atop the other, and then the
top one continuously is pumped full of steam, which “melts” the sands enough
that they ooze into the lower well and can be pumped out.
As one can imagine, quite a lot of natural gas and water is
needed to keep pumping the steam in and the tar out. In fact, every barrel of
oil produced uses two to five barrels of water. Furthermore, the process of
creating oil from tar sands is “carbon-intensive,” resulting in three times as
much greenhouse gas emissions as conventionally produced oil. The land has to
be cleared before mining can commence, and though naturally “steps are being
taken” to mitigate against the negative effects on local plant and animal life,
one has to wonder how much can really be done when taking huge swaths of land tearing
away everything above ground and all the topsoil below. Furthermore, the
Alberta tar sands are located on a delta used by hundreds of species of birds
as a breeding ground. Not only is the
landscape annihilated for mining operations, but tailings ponds (pools of
waste) sit on the surface throughout the area, threatening disaster in the
event of failure and leakage. Even when all is well, tailings ponds are
dangerous to the wildlife who mistake the toxic ponds for normal, safe water
features.
Of course, as with anything there are costs and benefits.
Although dangerous, deriving oil from the tar sands of course has its
positives, too. These are almost entirely economic. For example, the oil
industry has hugely improved the Albertan economy, providing jobs and future
prospects for expanded production. The United States and Canada each benefit
from having this near and fairly secure sources of the oil we still very much
need, and of each also has the pleasure and convenience of doing business with its
neighbor.
Finally, since Alberta is landlocked, getting the oil from
the source to the distributor means building pipelines, which comes with its
own additional demands on the environment as well. It’s easy to see why the
extension of the Keystone XL pipeline has become an issue as sticky as bitumen.
-Amanda Hudson, Legal Intern
