[TOMT][book] A book about a girl who goes to live with her grandparents in a place with lots of islands and something about a mineshaft that collapses. Late 1980s, bought it at the Scholastic Book Fair.

This book is on the edge of my memory. I seem to remember it being an Avon Camelot or Apple paperbacks book (maybe a very pale purple or periwinkle cover). It would have been purchased between 1988 and 1990 from a Scholastic book fair.

It was about a girl whose parents maybe died? She (Megan?) was sent to live with her grandparents (?) to Maine (?) (somewhere rural, decidedly North America, with islands) and she's deeply unhappy, although she begrudgingly admits that all the islands are pretty cool and she wants to explore them. She spends a lot of time alone and maybe befriends one other person. At the climax of the book a mineshaft collapses. There may have been supernatural elements, or they may have just been a product of the settling mine that everyone thought were supernatural. Everyone spends a lot of time warning her about the mineshaft.

I bought it the same day as: http://www.goodreads.com/book/show/1686230.Ghost_Cat and it had a very very similar tone of weird suspense. I actually thought that Ghost Cat was the book I was looking for at first, but this was definitely a mineshaft, not a house.