If unrest is increasing due to over population, the world must not be as liveable as you think it is. Go into the summary page and look at the colony cost. Unrest doesn't increase just from a lack of workers. You need an installation called "Infrastructure" to get living space for people on worlds with a colony cost above 0, even if it's only 0.001. One thing to check is to make sure the oxygen content of the world isn't above 30% - if a world is all oxygen it's too dangerous to live on so it will have a 2.0 colony cost. Add some gas of another type, like nitrogen or safe greenhouse gas (if you need to change the temperature too).
As far as population, 0.19 million is nothing in this game. You need 50,000 manufacturing workers for every mine - so 10 million for 200 mines. The amount of manufacturing workers you get from a population will depending on the colony conditions - highly populated worlds need more service industry, high colony score worlds need more agriculture. A highly populated world like Earth only has 20% of the population set aside for manufacturing. Smaller populations might get 50% or more. In your case you probably need at least 20 million population to operate your mines, plus more for the factories.
I normally send at least 50 million people to all my new colonies along with 500 automated mines (if it has good minerals) and 200-500 factories, depending on how quickly I want the place to be set up. I then ship in missing minerals if it needs them and have the place build itself.
Another thing you could use is engineering brigades. You need troop transports to move them and you build them in ground unit training facilities, I believe each engineering brigade takes 5 troop transport bays (same as how 1 construction facility takes 5 cargo holds) - but they are 1/2 the size of cargo holds so you can put more on a ship. They work just like a construction facility, but don't require civilian workers to be on the location. You could ship in duranium and some engineers to build the colony infrastructure if you didn't want to build it all on earth and ship it in from there. Engineers are real useful for setting up things on unliveable rocks too, like a sensor base on an asteroid.