question about the civil tile acquirement

[Chris0War]

Another post stated that resources should be about 6 tiles at most for the civil population to take advantage of this but in my current game there are ample opportunities, such as oil and rare metals that don't seem to trigger a response, metal and more or less scrap tiles are more in favor. Is there a specific reason for this ?

[Twotribes]

the distance determines strain on the Zone. And if to far will lessen the gain from those resources.

[Chris0War]

ah oke, hence the 6 tile rule