The crushed stone output from a 42- by 48-in. jaw crusher, with a closed setting of 3 in., is passed over a vibrating screen having two screens, the first with 2f -in. openings and the second with 1
-in. openings.
The permissible efficiency is 85%. The stone has a unit weight of 110 lb/cf when crushed. Determine the minimum-size screen, in square feet, required to handle the crusher output. If the screening unit is 4 ft wide, what will be the nominal screen sizes?