The bitumen is heavy oil with a low API. Extraction required strip mining similar to the way coal was mined. The sands were crushed and the heavy oil was separated from the ore using a flotation system. The heavy oil was then either upgraded to synthetic crude by cracking and the addition of hydrogen or mixed with diluents and shipped to a refinery area capable of processing the heavy oil mixture. Deeper tar sands were developed by the drilling of parallel horizontal wells in a process called SAGD (steam assisted gravity drainage). The steam was piped down the upper well and eventually melted the tar. The heavy oil sank to the lower well bore and was pumped out of the lower horizontal well to the surface. There is a third process called THAI (toe to heel air injection) that ignited the oil below surface using high air pressure to produce spontaneous combustion. The fire then melted bitumen and the bitumen was collected along with formation water and combustion produced steam condensate water at the other end of the well system. This process was supposed to upgrade the oil to a lighter variety as shown in lab tests. Early field test results indicated they did not upgrade nearly as much as was hoped. There were some remaining problems with sand and well control that have not been fully described. The process is yet in the R&D - pilot test phase.

I am not a chemist, but understand the bitumen is in the form of longer heavier polymers. These longer hydrocarbon chains were manipulated with expensive processes in order to render salable crude.

What is bad quality today might be of precious quality in the future.

Have you ever heard of the Pitch Drop Experiment? That's what comes out of tar sands. Perhaps you can see from the picture why its so difficult to turn into fuels like gasoline.

The term "gold into lead" might, at least partially, refer to the fact that this stuff can be used to make plastics and some other useful materials that are of enourmous value to modern society (especially modern medicine). Putting so much effort into turning it into fuel really is rather silly.

rainsong is right to say that the viscosity of bitumen has to do with the length of the polymer molecule in it. For polymers, the longer the molecules, the harder they are to pull apart from eachother.