Complex sentence: The Confederates had over 2,400 casualties (mostly dead) and more than 1,600 soldiers were made prisoners, while the Chilean army had about 1,300 dead and 400 injured.
Split into simpler sentences: The Confederates had over 2,400 casualties (mostly dead) and more than 1,600 soldiers were made prisoners. The Chilean army had about 1,300 dead and 400 injured.