With no other option I tried to pull a Cat5 cable through but unfortunately the cable snapped 42 feet into the pull.

That's interesting. How did you pull it? Were you able to push a snake all the way through?

One possibility as to what has happened is that the conduit, probably EMT, has filled with water as every below grade run will. The water caused it to corrode and cause the cable to stick.

Another possibility is that the lube that was used dried out, again causing the cable to stick to the conduit wall.

If you were able to get a fish tape through that's a good sign. I will have to do some looking but I do remember somebody who makes a kind of solvent that you can pump into the conduit that will soften whatever is in there. If that is sucessful and you are able to pull everything out there is a wire brush that you pull through to clean the garbage out.

When you pull back in make sure the lube you use won't dry out and stick everything together again.

-Hal

CALIFORNIA PROPOSITION 65 WARNING: Some comments made by me are known to the State of California to cause irreversible brain damage and serious mental disorders leading to confinement.