While in theory, this should work, it doesn't in reality. I ask the same question a long while ago, and then tested the answer. Unless the mining rates have changed in the recent expansion, mining bases actually have optimal designs:
a) Mining stations. 3 Extractors until you research the first technology that improves your mining rate. Then 2 extractors. In theory, 1 extractor after the second technology advance but I have never had the guts to test it.
The game economics plays on 19 day cycles. This fills up cargo space in the station and will maxmize the cargo shipping to the nearest space station.
For whatever reason, even doubling the cargo space and the extractors doesn't change the actual units transported back to the space station.
b) Gas stations. 4 Extractors, reducing 1 and 1 for each tech advance. In theory, 3 should work the same as the mining extractor, but it test I have done seem to show that 3.5 is optimum in most gas giants.
c) Lux extractors. 4 to 5 Extractors, varies depending on the luxury. Doesn't reduce based on tech.
There is some trade off due to the % of the item at the location - the higher percent the lower the number of extractors needed.
And distance to the nearest startport can make a difference but not as much as I thought anyway. It is more in the reduction of transit times, not really in the collection times. Mining stations in really out of the way locations just aren't visited as much as other, but this depends on how many cargo ships you have.
Just as a note, based on some small test, a small cargo transport with 4 standard cargo holes is 50% more effective than one with 3 - so it is very worthwhile to change the small cargo transport to 4 cargo holes. I saw some improvement but all the improvements were less than the % increase in cargo holes for the medium and large freighters.