If the stovepipe is close enough that finish damage is a concern, I'd first have a building inspector or engineer or someone like that reassure me that having the stovepipe that close to the mantle doesn't present fire issues.

That said, you would want a finish that brings out the grain and is easy to refresh and repair. That would mean Danish Oil, dewaxed shellac (Zinsser SealCote), genuine tung oil, Waterlox, or something like that. That rules out polyurethane and most varnishes. I'd worry about film-forming finishes in general cracking or bubbling, so I guess I'd tend to lean toward Danish oil or tung oil rather than shellac or Waterlox.

Thanks rstanny. I was beginning to think no one was going to answer.

It is not the stove pipe I am worried about, that comes into the brick under the mantle. The stove we have is so large it actually extends up past our mantle (the hopper in which you load the coal into). The top of the stove is not nearly as hot as the middle of the stove and I am not worried about the mantle catching fire. I am worried that if I finish with the wrong thing it will dry out too quickly and I will have to either keep re-finishing or like you said, there will be cracking or bubbling of some sort. I will read up more on the Danish oil and tung oil and see which is more appropriate for my purpose. I have used tung oil in the past, but not Danish.

Thank you very much for your help.