I've been mining for a few months now, and I prefer to mine in bulk. I take seven or ten tea cups into the mine with me, and mine without picking up any of the ore. Then, I take a couple dozen trips in and out of the mine, carrying ore to the smelters.
Just a few minutes ago, I finished off the last of my tea cups, grabbed all the ore I could carry with me, and dumped ore and tea cups outside.
And, to my great astonishment, when I returned to the mine, I discovered that all of the ore had vanished!
I had only left the mine for a few seconds. So I know it wasn't thieves.
Help?