I took some times to research for icons (thanks OpenGameArt and the multiple contributors again) and did some Photoshop work too.
Here is a crop of screenshot of the result, nothing AAA as usual but better than ton of dry texts:
For the Nuclear Fission Reactor, the icon of a box with a number inside of it indicate that is an infrastructure kit that can be assembled to a level 1 infrastructure (the reactor itself). The number on the right indicate the number of them present into the colony's storage.
For the Mining Site, this infrastructure is a one that must be built by using construction workforce and local resources. It is easy to see that it is not an assembled infrastructure since it doesn't have the box icon nor any indication of stored units.
The warning icon indicate that the infrastructure's requirements aren't met to be built and so its text color is red, according to the filter actually applied in this example. This warning can also be applied to infrastructure kits that aren't compatible too.
The rounded icon indicate for which environment the Mining site can be used, in this case the green one indicate Free Environment only. FYI it doesn't reflect of the reality of the Mining Site's data yet since the test and display aren't finalized in the code (it will be tomorrow night).
So there are three environement icons, two are already made and one is in the making.
I also continue to working on the interface for the configuration of a selected infrastructure owned by the player, and also on the setup of the assembling and building of an available infrastructure.
Stay tuned :)