I've piled up at least 200 ores.
And I would think if you ran into the limit, you'd get an error message when you tried to use the shovel, and not lose your shovel. Like the "production queue full" error message.
There are definitely streaks, hot and cold. Didn't realize that just stopping for awhile could change your luck that way. I thought it would just continue when you resumed mining. Hmmm.
