If your fleet doesn't have the Tier 1 Mine completed, then you can't go to the Mine itself. You can go to the space map. Also, if you have Tier 1 Trade or Development done, but not the Tier 1 mine, then you can't access the Warp Cores or Engineering Consoles that were provided for until the Mine is upgraded. No Mine means no vendor.
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In every place,
The deeds of men remain the same..."
R.I.P. Leonard Nimoy