How does mining asteroids work? I looked in the gold edition manual for it and it just said it added 'resources' to a planet. I assume it means production.

Also, how does upgraded mining bases work? The manual said at the 3rd (highest) upgrade, you can get up to '20 resources' for a colony.

Does that mean if the planet is say, right next to it, it will recieve +20 production bonus (I understand the reductions based on distance)? I assume its 20 shields and not 20%. Does it split between social and military or?

Just wondering, I just dont understand what having mined these asteroids did for me.