· Dry or wet, not sticky: 6/1 to 8/1: Sand gravel, recycling: Vertical shaft impactors (autogenous) Soft to very hard: No limit: Dry or wet, not sticky: 2/1 to 5/1: Quarried materials, sand gravel: Mineral sizers: Hard to soft: Abrasive: Dry or wet and sticky: 2/1 to 5/1: Heavy mining: Crusher buckets: Soft to very hard: No limit: Dry or wet ...