[yarddog]

You could use a cut off wheel with a Dremel tol and cut the bolt off even with the pan. You will probably use two or three.

After you remove the pan, you can use a broken bolt remover to back it out.

[roadcat]

You could use a cut off wheel with a Dremel tol and cut the bolt off even with the pan.

I have used cut off wheels on my Dremel tool to slice slivers off the nut. Once a lot of metal is cut away from the nut, you should be able to chisel away the remnants from the stud. Chase the stud with a die tool, then use a larger washer with a new nut to refasten tight.