Refining - Net Mineral Yield - How it works

First, select the equipment quality on the station you want to refine and
whether you have one of the 'Beancounter' refining implants.
Refining Options
If the browser doesn't refresh the table values immediately on a change, click the 'Submit' button.

If you haven't trained the skill Refinery Efficiency, continue with the first table ('Basic Refining').

First, go to the column that represents the level of the Refining skill, which is 4 in this example.
Then, go down to the row that represents the level of the Ore Processing Skill, for which we assume Veldspar Processing Level IV.
Basic Refining Table


So the value marked with green, 98.600%, means that
  • on a station with 50% equipment
  • with no refining implant
  • with Refining IV
  • and Veldspar Processing IV
you are able to get 98.6% of the Tritanium out of the Veldspar you're trying to refine.
Note that the station owner might take a share of those 98.6%, depending on the standings.