Factorio Forums

Placing quality modules in big drills can sometimes cause produced items to be deleted. The quality ores that would have been produced are still logged in the production statistics, but no item is actually placed on belts. Outputting to a chest does not have this issue.

This testing setup was run for ~10 minutes and produced 2x as many rare ores in the chest output version. Running only the belt output version still shows that epic and higher ores are being produced, but the chests remain empty.

My only guess is that this is related to a combination of the productivity bonus and the belt stacking of the big drills, because this doesn't seem to happen with regular drills.

Thanks for the report however the items are not in fact deleted. They are being buffered in the drill until a "full belt stack" is available at which time they will be put on the belt.