That kind of strip mining is only done on shallow sites. Since most of Alberta’s deposits are deep well, they use thermal in-situ extraction methods (usually either SAG-D or CSS).

Most oil sands sites in Alberta use SAG-D (steam-assisted gravity drainage). They drill two wells on the site, one slightly higher than the other, then inject high-pressure steam into the site to decrease the viscosity of the bitumen, which then gets pushed up the higher well. The bitumen gets processed after that (because we can’t use oil with sand in it), which creates a lot of waste water.

What this article is talking about it the disposal of the waste water after, which is injected into deep well sites. Though I’d be interested to see if there’s more research into “induced seismicity” from the extraction process as well.