This is not a public domain image. If you look at the source, it clearly states that the image is from Suncor Energy, Inc.
http://ostseis.anl.gov/includes/dsp_photozoom.cfm?imgname=extraction_separation-600.jpg&caption=Tar%20Sands%20Extraction%20Separation%20Cell%2C%20Alberta%2C%20Canada&callingpage=%2Fguide%2Fphotos%2Findex.cfm&callingttl=Oil%20Shale%20and%20Tar%20Sands%20Photos&source=Source%3A%20Suncor%20Energy%20Inc.