Coal mines closed at full capacity.

[CodFace 0]

But I have coal storage lots in my trade depots, set to use locally. But my coal mines are stuck on close, even though they have max delivery vehicles. I cant even see any coal delivery vehicles on the map. The god damn mines are stuck on "closed at full capacity" when my damn power stations are shutting down due to no coal coming in. I'm having to now import coal to keep my city powered!!

[Yamofo 1]

Try to find the cause. In region view you should be able to see if you trucks are stuck on the highway. If they are not...

 

At the sub-level of  the trade depot. (have 40K on hand) Bulldoze just the trucks. Now plop them back in. I've had that work.

 

There are other issues I've yet to fully comprehend. I had a processor factor manufacturing 9600 crates a day pretty much next door to my trade depot. Then I had the bright idea of moving the whole thing directly across the street. I wanted to make better use of space. Sadly the replacement plant has never produce more than 4800 crates since.

[simmarine 7]

Agree with Yamofo, watch to see if your trucks are getting stalled anywhere and check to see if your trade depot lots are balanced. One other thing I have tried is to change a road or even add a dirt road near a site. It seems to change how the game uses traffic and you might get lucky and find the balance.