I'm a strong believer that a lot of personal experiences on this site may well be related to that state between awake and asleep and not necessarily anything to do with ghosts or spirits and gave a pretty good explanation of this the other day, but this brought back a memory of something that happened when I was about 19 when I worked down the mines.
I used to work all night shifts in a coal mine. My job was sometimes to watch over the end of a conveyor belt making sure that things were running smooth, no blockages, pile ups etc. There were times when there was little to no coal on the belts so being night shift, and very few bosses around, you could occasionally catch a nap here and there, pretty illegal in the mines and a sack-able offence. One night, I was doing just that... I'd just had something to eat and decided just to relax my eyes a bit. I wasn't asleep, but I think I was in that place between sleep and awake, when all of a sudden I felt 1 or 2 quite firm taps on my shoulder which woke me. I looked around and no one was there. I did see some helmet lamps quite far down the tunnel so there were obviously some people coming towards me but no one was near me. There were about 2 or 3 people coming toward me in the tunnel, so just to be on the safe side (in case they were, what we called 'Pit Deputies',...like supervisors) I started to pretend I was doing a bit of work. As they got closer I realised that they weren't just pit deputies, (who only probably would have sent me to the office and fined me £5 of my wages), but one was actually one of the big bosses of the colliery. Had they caught me, I would have been sacked on the spot for sleeping.
I thought about this quite a lot over the years, maybe it was nothing more than just a sleep thing, or could it have been a ghost or 2 of long dead miners acting as "lookout" for their fellow workmates. Who knows! Definitely a weird moment thought.