RE: I suspect how reco for 1/2 and 1/4 can b sameSounds logical to me. Grinding ever smaller doesn't mean ever greater recoveries. There is an optimal size for all ores. When you are at/near optimal, less effort or more effort won't significantly change recoveries. What is being learned is that optimal looks closer to 1/2" than 1/4" for the lower grade material. I wouldn't be surprised if they sent back R190 ore for retesting as it showed lower recoveries at smaller grind size - they may have been over grinding.