Toasteh's Veinminer mod, updated by Ogliss
Github[github.com]
B19 Version HERE
original mod HERE
This mod lets you designate all connected minerals to be mined, even if you can't see them.
Works on any mineable tile including stone.
V1.2
increased compatabilitty, removed DesignationCategoryDef & swapped to xpath patching it (At Menhi's suggestion)
V1.1
Updated to R1 and I think I fixed the crashing bugs though veinmining stone usually does a weird pattern on large mountains.
V1.0
Initial release
Obselete as of RimWorld 1.5, as a similar feature has been added to vanilla