The word ‘mine’ initially signified crude ore and has since come to mean the place from which crude ore is taken.
In this sense dreaming of a mine suggests prospecting for crude material, which can be refined, whether that is raw emotion or unexpressed feelings.
This is also one of those symbols that can actually be a wordplay.
The objects in the dream are ‘mine’. Dreaming of a miner is that part of us that is prepared to explore and use the crude material.