What about allowing unused population (i.e. population not assigned to a task) to have the same ability as a construction factory/mines.
E.g. for every 500k of unused population, you have the equivalent of an extra "free" CF and mine.
In this way, you have civilisations that have just discovered non-neutonian minerals can start mining and construction to build a non-neutonian economy (otherwise you have the catch-22 situation, where you need non-neutonian minerals to start getting/using non-neutonian minerals).
For races that already have the ability to get/use non-neutonian minerals, this will have only a small effect, as you are often in the situation where you:
a) only have small colonies (in which case you only get one or two "free" mines/CF anyway)
b) have an established colony, that already has mines/CF's (in which case the extra "free" mines/CF only add a few percentage increase to the amount mined/used)
c) have a homeworld with a huge free population, in which case the planet is almost always going to be mined out (and so the extra "free" mines aren't being used), and already has a large number of CF's (in which case the extra "free" CF's only add a relatively small increase to the construction ability of the planet).
Comments?