Make the mine props in mineshafts actually do what they're supposed to.

Normally, when one disturbs sand or gravel in the ceiling, it causes all adjacent blocks to collapse also.

For mineshafts, have the mine props and cap pieces that decoratively hold up the ceiling, actually hold up the ceiling, preventing cascading collapses of gravel or sand within a certain range of these structures.

Before a sand or gravel block decides to fall because another already has, it should check for any *pre-generated* mine props. If there is one within a certain range at roughly the same Y-level, give or take, it is prevented from falling (and may break the chain reaction of any additional ones falling).

Because this would depend on pre-generated mine props as recognized points of interest, this means players can't make their own mine props that will work as well as the originals, nor can they break pre-gen mine props and then simply replace them. They have "disturbed the environment" and it won't go back to the way it was.