Question 4 (15 marks) - Density 4.9g/cm3 4. The pyrite is fed at a rate of 13000kg/ hour to the secondary jaw crusher. The crusher is operated in a dosed cycle, with a recycle of 27000kg/hour. 4.1. Using Bond's third law calculate the total energy consumption in kWh/tonne if the energy efficiency of the crusher is 78%. (10) 4.2. Shortly explain how a jaw crusher works and the stressing mechanism used for size reduction