1) the planet is inside the ring
2) I have built several mining modules
Do you have a mining starbase built around a floating crystal thing, or a free standing starbase? Assuming you haven't renamed it, when you select it you will see something like Mining Starbase 237 or Military Starbase 192. Influence or Economic are other possibilities.
If you see it named Mining Starbase, it does NOT give individual planets bonuses, it benefits your entire empire. To get the other choices, move a constructor to where you would like to build the base and select construct, which you will find left of center along the bottom of the screen when you have the constructor highlighted. Only starbases named Economic Starbase #xxx will give a detectable bonus to planets in the area.
How do I make them "send resources" to a planet?
Once the asteroid mine is finished building, there will be a faint line leading to your nearest planet. To change where the mine is sending resources, highlight the asteroid mine and locate the button in the lower right of the bottom center window labeled "assign". This should bring up a different green cursor, which you can then use to select a new target. The resources you receive diminishes quickly over distance, so keep distance in mind when you are picking planets to receive resources.
