Mining mechanics

(Game version: DW Universe 1.9.5.12)
 * All resource extraction (mineral/gas/luxury, either on ship or station) has extraction bonus factor of 6.2, rounded down. So with starting extraction tech 3 minerals (20 gas), one extractor can mine 18 resources (124 gas) on a 100% planet.
 * Extraction happens each 6th game day.
 * Max extraction amount of resources (mining cap) per mining turn per ship/station is planet concentration (100 max). On gas planets it is planet concentration * 4 (400 max).
 * Planets mine each mining turn half the concentration (concentration 100% gives 50 resources).
 * Storing mined resource on mining stations: each mined resource has about equal portion of cargo space. when it's filled-up, mining for that resource stops.
 * Mining stations have cargo space bonus of about 3.5 (1000 "designed" cargo space is about 3500 actual space)
 * Extractors on colonized planets don't work, but pirates CAN mine independent colonies.
 * Extractors work even if station does not have needed energy (no fuel and no energy collector)

Consequences
 * Formula for calculating needed amount of mineral/luxury/gas extractors for maximum yield:
 * mining cap (100 or 400) / 6.2 (mining bonus) / current extraction rate
 * With starting extraction rate 3 minerals : 100 / 6.2 / 3 = 5.38 or 6 extractors (5 with some loss)
 * With starting extraction rate 20 gas : 400 / 6.2 / 20 = 3.22 or 4 extractors (3 with some loss)
 * Player can NOT extract more resources from a planet by adding more than 6 extractors
 * If you REALLY need one mineral/luxury, don't colonize that planet (planets have halved extraction amount, compared to max-yield mining station.

Observed in-game behavior
 * Most stations are filled-up with resources and don't mine. It seems freighters don't visit them often enough. Yet a player needs to build them, or AI will take those resources for itself.