The entrance to the Brownstone Mine I use is inside the tram room where the cable runs back around. At the back of that area is a ladder that goes up into the mine. I didn't know about any way in near the switch backs. The hole you speak of from Pine Creek probably connects to the drill hole.
As for the Pine Creek Mine i'd rather not say where it is. There is always the chance that word can get around and the mine will be closed off. I don't mind mentioning how to get inside Brownstone because I have explored everything that can be done without climbing gear which was plenty enough for me.
