If I upgraded the gold resource technology and I send one worker there do I get one gold even though you need 2 workers there to get 1 gold?
Yes. You get one more gold every time you visit. If the site didn't have an icon for one worker doing nothing you would get nothing, though.
Are you sure? The rules say, you only get the additional resource if you received a resource from that location.
Ah, directly from the rules:
Every time a player receives any Gold, that player gains
one extra Gold. This means that activating the Gold Mine
with a single worker will allow the player to gain one Gold.
That seem contradictory... if you active with 1 worker you get NO gold so how do you get an extra. Seems like a NOT is missing in that second sentence.