Ann: Exceptionally High-Grade V-Zn-Pb Concentrate from Abenab, page-18

eventually one also needs to take into account smelter recovery

ie if concentrate recovery is 80% for Vanadium and smelter recovery is 90% for Vanadium then final recovery is 80% * 90% = 72%

Wondering why it is taking these guys so long to get mining , given back in early 2020 they thought they would be mining by that Christmas 2020 , dont get me wrong I like the project due to the type and tenor of mineralisation , just seems they are taking a long tome to get what should be a simple low CAPEX operation up and running