Factorio Forums

The electric mining drill (not the big mining drill) is belt stacking items with sufficient mining rate. I don't remember this previously occurring (although I could be wrong), and it seems unexpected/unintended to me. At the very least, the 'Bonuses' entry that lists entities affected by "Belt stack size bonus: 3" seems wrong because it doesn't show the regular mining drill. (It only shows stack inserter, big mining drill, and recycler.)

Steps to reproduce:
- Have a SA save with belt stacking researched. I used the editor with editor extensions for ease of testing.
- Have some combination of high mining productivity and low belt speed - my demonstration save has MP 100 and yellow belts for the most obvious reproducible test case.
- Mine a patch with regular electric mining drill onto a belt and observe more than 8 items per belt.

I expect that regular mining drills should be unaffected by belt stacking and can never stack items on the belt.
Here is an image of the problem in action: https://imgur.com/a/qjQv6Dk
Based on my searching, perhaps this is related to this recent fix? viewtopic.php?t=129365
A reproducible savefile is included, but it is quite easy to reproduce using editor extensions.

Thanks for the report. Issue is now fixed for 2.0.59. It looks there was some amount of miscommunication about game design and fact that electric drills are not supposed to stack was lost when fixing a related bug report.