I put some iron and gold ores in a chest right before I exited the game. When I went back to the game later on, the chest was empty!
I'm not sure if the problem can be reproduced, but I'm guessing it's problems with the game saving automatically.
The gold and iron veins remain mined (ores are not there anymore), and the mined minerals were gone too. This can be a big headache for many players, I hope it will be solved asap. Thanks!