dodegaard wrote: So do you happen to have any advice on recovering that file so I can move it to another drive? That is the part I am most concerned about.
I would use ddrescue over dd however while dd is a part of OS X ddrescue is not. For OS X I had to download the source code and compile it on my system. If you don't have Developer Tools installed like a gcc compiler and make or Xcode I can upload the version I compiled on my system. You might be able to find a compiled copy for OS X on the Internet, I don't know for sure as I prefer to compile from source code on my own system.