CALGARY — Wildfires at Fort McMurray, Alta., have forced the shutdown of about a dozen mining and thermal projects.
Here's what you need to know about how they will be restarted and how long that might take.
What is the difference between an oilsands mine and a thermal oilsands project?
An oilsands mine recovers heavy, sticky bitumen crude from a strip mine using shovels and trucks and then processes the ore to remove impurities such as sand, clay and water. Most miners also upgrade the bitumen to make a more valuable light "synthetic oil" product to be shipped to a refinery.
A thermal project uses wells into which steam is injected to melt the bitumen and allow it to be pumped to the surface. New thermal projects take many months to reach full production because an underground "steam chamber" has to be created in each well to ensure an even flow of bitumen.
What happens when power and heat are removed suddenly?
The short answer is that all the bitumen, whether in the upgrader or deep in a thermal operation's well, begins to revert to a product that can be as solid as a hockey puck at cool spring temperatures. In short, it can gum up the works.
Rob Bedin, a director at RS Energy Group in Calgary, said a careful shutdown will result in bitumen being cleaned out of vessels and pipes throughout a mine's upgrader, while a thermal oilsands project operator will ensure the steam chamber remains heated or will inject solvents to keep the bitumen as liquid as possible.
Producers shut down plants and wells for maintenance or to comply with regulated inspections, often annually or semi-annually.
How long will it take to get the projects operating again when the fires are extinguished?
Mining: The physical gathering of bitumen ore at surface can be restarted as soon as the trucks and shovels have drivers. But processing and upgrading systems need to be started more gradually, Bedin says. A project that has been properly shut down and kept warm could be ramping up in about a week. A cold upgrader could require two weeks or more.
Thermal projects: Usually take longer to return to full production, perhaps three weeks, because steam has to be re-established in a network of surface supply lines leading to what could be dozens of wells, Bedin says. The ramp-up of production of bitumen will be gradual, depending on how much steam is available as well as the operation of pumps, valves and other gear.