Ok, you can try to build asteroid/comet mines (if available) to squeeze some profit out of that colony in addition to taxes, but given how expensive those buildings are on poor planets, you'd be better off with prioritizing other systems first.
As you can see, you'll indeed make a profit. But first you have to invest 6300 for asteroid mines and 10800 for comets. Even if you happen to have that kind of cash, it will take 63 and 54 turns to get the investment back.
However, normal planets with asteroids/comets are a treat. Add a level 1 mine and you're rolling in the cash. Good profits, just watch the popularity. Once your popularity hits -8, you'll be facing riots.
(forgot to add a tech complex. pollution should be -2)
Core mines may sound attractive, but you can't build them everywhere due to their massive pollution factor. And if the environment (dead planet in this case) was a crappy place to live in from the beginning, making it even worse won't add to the population's happiness.
On ideal planets, core mines are feasible. You'll have to watch out for eventual popularity drops due to bureaucracy and overcrowding and you'll probably not be able to tax your population until they bleed, but it should be ok.
Of course, you can kiss your growth rate goodbye but at some point in the game it's worth it.
And that's the one you're never going to get:
The custom campaign I used to make those screens can be found here:
tm.asp?m=2305202
