At a couple of points, hydrogen was mentioned as limiting resource for InSitu tar sands processing; which techniques use hydrogen gas, or was this meant to refer to the hydrogen content of the bitumen?

Its used for hydrogenation which is capping the ends of broken carbon chains. The primary source is methane.

http://members.aol.com/profchm/Petroref.html

http://en.wikipedia.org/wiki/Steam_reforming