Crash while mixing: file shows in folder, but unable to open...and it's an hour and a half

Can't you start the mix again?  I am imagining/hoping/expecting you would have saved the project's final edits prior to starting the mix down.
 
How far do you have to go back to get to a working version of the project?  Even if the whole project is corrupted, don't you have a backup copy?
 
Bob Bone

Yeah, sorry guys: I posted after working 36 hours straight on a project and wasn't clear. At all. hopefully this muddies the water less:
The project file is fine (and yes I have copious backups of previous versions) and save constantly.
The actual question was: is it possible to recover the corrupt stereo mix down of the project that I can see in the folder (1.4GB of data, says it's a.wav file but cannot be opened by anything except as a raw file in Audacity. But when it's opened, it's unusable). The project itself is one hour and 32 minutes and I got within fifteen minutes of the end when the error occurred, so I didn't want to have to re-bounce the entirety of the project if I could recover the portion that was finished, bounce only the last fifteen minutes, and merge the two sections. Unfortunately, I ended up re-bouncing the entire project. This time in thirds (just in case it happened again...it didn't) and then merging those.
I am doing a real time bounce on this project, as some of the soft synths sometimes drop notes and occasionally I hear an effect sound incorrect after Fast Bouncing.
So my inelegant solution was to re-bounce the project in portions in case something bad happened. By overlapping on each portion, I also kept tails and FX from a previous section or going into the next: i.e. instead of breaking up the project into 30 minute segments, I bouncinged 32 inutes of the first section, 34 of the next (2 minutes prior and after what I needed), and 32 of the last section (starting two minutes before the section was interested began)