I don't store cobble in the collective storage since it wasn't neccesary to, but I have at least 6+ large chests full of cobble (some in the warehouse, some in the mines, and some scattered elsewhere), so I'm not even close to a shortage of cobble.
I can easily spare a large chest or two, or three to put into collective storage.
Seriously though, how can people be low on cobble? Not that hard to create a quarry.
"maybe we should have monthly quarry digs from now on."
Maybe not monthly, but yeah having quarry digs would be a great idea. Theres several around, Kipz has his massive quarry, Narus cafe/station thing still needs to be quarried out, and I have my quarry.
Mine could be a bit problematic though because theres some big caverns down there, so better wear feather falling boots. Lava shouldn't be an issue.