These are all located at the head of Straight Hollow near Dante VA. This was a coal mine complex that opened sometime before 1912 and gradually died in the late 50s. It was operated by Clinchfield Coal Company.
This is a 1914 adit. It’s hard to see, but before the “1914” is a capital “E” and, on the other side, is a capital “R”. I have no idea what that’s all about.