MINERAL PROCESSING & EXTRACTIVE METALLURGY1 min reference notePrimary & Secondary Crusher Circuit Reduction Ratio OptimizationSource notes β linked publications and standards below; organisations and authors named there do not author or endorse this page.1. Crusher Reduction Ratio (RR)Reduction Ratio RR = F80 / P80. Target primary jaw RR = 4:1 to 6:1; secondary cone RR = 3:1 to 5:1.PEER-REVIEWED TEXTBOOK & JOURNAL CITATIONSMetso Outotec. (2021). Basics of Comminution Handbook. [Access Reference]