You should really start making automated mines. Trying to build enough infrastructure to actually have population enough to run conventional mines is going to cost you VERY much, if it's even possible to put a non genetically changed colony there.
Also, try to find fast a new source of duranium, as you have seriously little of it in your planet. It's basically the basic building block, and pretty much uses it. You'll be hurting if you don't get a new source ASAP. If you're luck some body in the system will have over a million duranium with good accessibility (say, 0.8 to 1), but if not, for now focus on the good accessibility bodies. You'll probably want a huge source of Sorium sooner or later, specially if you get extra solar mining, as mass drivers can't drive the minerals through jump points, even if you had gates, and therefore you'll be doing a good deal of shipping. You have enough for a pretty long time though, so don't worry too much. And you'll need a new source of mercassium, with all you have in your planet you can't even finish the production you already started. It's basically used for research labs, so it won't fatally cripple you in the short run (make sure you keep some small reserve for any punctual need, just to be on the safe side), but it'll make you take even longer to build a decent research base. You'll also need more neutronium when you get your shipyards up and running, specially when you start making warships.
Basically, you need to focus on Duranium ASAP, and neutronium, as if you run out, you'll be locked out of your ship production. Mercassium so you can pick up your speed, but if you can't find it'll won't cripple you on the short run. Ideally you want a planet with over a million of each, with high accessibility for all of them. If you can't find one, focus on finding a planet with all of them with high accessibility, or even sacrifice a little accessibility if the planet have all of them (as you can focus your mines in one planet, it can be worth the loss in efficiency). Try to keep them all around 0.7-1, but if you can only find planets with high accessibility for one of them, even a 0.3 accessibility can be worth focusing your mines. Still, you'll need lots and lots and lots of duranium, so if you have to choose between a high-accessibility duranium and a high accessibility anything else, go for the duranium, even if it hurts the others a little.