Hi Ken -
there was a VERY detailed book re Saltville and the battles that took place there. It was written by William Marvel as part of the Howard Virgina Civil War book series.
Suggest doing a search on Abebooks.com; you might find a copy of it....
I had a Yankee ancestor in the 26th KY Infantry who was apparently present during the first battle of Saltville (see URL below).
good luck,
Kenneth Byrd