It seems once I finally switched to nuclear power, that after I removed all Regolith furnaces that my miners stopped working, even though crystals are required to get Regolith through building mines constantly (which I hate doing).
I believe the bug is that you require a Regolith Furnace in order to harvest crystal, even though you have a Raw Materials Depot placed and have plenty of storage.
I'm on the web app, in Firefox. I can't find the version number in game anywhere, but its whatever the current active version is.
I suspect the bug is an oversight, in forgetting to enable miners to drop crystal off at other locations other than Regolith Furnaces.
raw material depots do not store crystallines and you probably dont have any other buildings that store crystalline