Ann: Exceptional Vanadium Grades Confirmed at Koitelainen Vosa, page-154

I assume "mass recovery" to mean all the material left over after concentration and not discarded to tailings, which then carries the improved concentration value of v2o5. This is normally how such things are stated. In this example, 1 unit of stuff is reduced to 5.1% of its original bulk, rated at 2.6% v2o5, which is 33% of the total contained metal. As I previously stated, this is behind but comparable to AVL's 44% oxide recovery, and the sampling is from the regolith so is probably oxidized.

We could also do it in terms of volume and % only, eliminating the gravity problem. 1m3 x 5.1% = 51000cm3, x 2.6% = 1326cm3 / 4000cm3 = 33.15%. Whatever weight of v2o5, the recovery rate is the same, relative to the 100% concentration.