Cold Mountain Battle Scene

My son had to do an exam on the book of this film today - giving me an excuse to show this opening scene. It doesn't happen in the book apparently but it depicts the Battle of the Crater - part of the battle of St Petersburg - the crater was the result of a mine dug underneath the Confederate positions so obviously of interest to me as my Grandfather did something similar in WW1. However it was not a success - reading the wiki on it you get the impression that it was ahead of its time. More on the Battle of the Crater

I found this piece on a page of the site History in the Movies which I will go back to soon - note the bit at the end - it isnt just me...
Q Was the battle portrayed accurately?
A. The opening battle sequence of Cold Mountain realistically portrays the gruesome nature of Petersburg's "Battle of the Crater." Union engineers created a massive crater with explosives in an attempt to penetrate the Confederate lines. Untrained Union soldiers rushed into the crater and got trapped. Confederate soldiers remembered the ensuing clash as a "turkey shoot," with over 5000 Union soldiers dying.What the film misses, though, are the many black Union soldiers involved in that battle. Probably this was a function of filming in Romania, with all-white Romanian army troops as extras. But though the Union army's racial diversity wasn't portrayed, the use of Romanian extras made for more believable looking soldiers. Young, gaunt, and sporting bad teeth, these soldiers are a far cry from the chubby, middle-aged Civil War reenactors who populate the battles in recent epics like "Gettysburg."