Mine Support

Supports hold up the mine's ceiling to prevent cave-ins.
Note: Mined tiles will still show dust animation (see Mining page) when under the radius of the support, to warn of cave-in tiles, but cave-ins won't occur under support.
Quoted from Loftar:
:<SuperDaddy> Does it count if the radius is touching part of the tile?
:<loftar> Well, to be precise, it needs to touch the exact center of the tile.
This means tiles covered by the support radius just slightly aren't supported.
Caution: Destroying a mine support underground will immediately cause a cave-in to occur, even if all tiles are supported by other supports.
==Support Radius==
All tiles marked in blue are safe to mine. Mining a tile outside of the blue area may cause a cave-in. This structure will support mining within a 9 tile radius.
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Note: Mine supports can be built on the surface and in houses; however, serve no function