Main character doesn't know they are dead until the end

It's a shot in the dark but I'm trying to figure out the name of a book I read in school at some point between 2005-10:

- Fiction
- Main character wakes up washed ashore (can't remember what caused it)
- Takes shelter in a cave, finds two guys dressed as miners
- I feel like the majority of the book took place with these two guys
- Main character eventually finds their way back home to their family, but it's like he/she is invisible to them.
- At that moment, it's revealed that the main character drowned and died, and has been a ghost for the entire book
- The two miners were also ghosts, died a long time ago.

Some of these details I'm a little fuzzy on e.g. there may have been more than two miners, and they may have been dressed as something else but I do get the feeling they were miners or something similar. Unfortunately I don't even remember if the main character was a man or a woman, or what the incident was that led the drowning.

It wouldn't have been a particularly large book, around 200-300 pages would be my guess - I would have been around 9-11 at the time of reading so it was a book that older kids could read and learn from.

The White Horse of Zennor and Other Stories
by Michael Morpurgo?

"Then there are the old tin miners that Cherry meets when she is cut off by the incoming tide..."

I second Michael Morpurgo. The story is The Giant's Necklace

Ah thanks to both of you! Michael Morpurgo is a name that rings a bell, I remember reading a lot of his books at school (Kensuke's Kingdom was a favourite) so I'm almost certain that this is it - I'll be visiting my local library fairly soon so I'll be sure to read them for myself to confirm.

Thanks again!