How often do the blowbars need to be turned or replaced?

This depends heavily on material hardness and cleanliness. When processing clean limestone, a set of blowbars can often process 20,000 to 40,000 tons before turning. When crushing highly contaminated urban demolition waste or concrete with high silica content, blowbars may need to be flipped or replaced every 10,000 to 15,000 tons to maintain cutting efficiency.