A Blake jaw crusher had the following dimensions: Gape=160 cm, open set = 24.4 cm, close set = 5.0 cm. The width of the hopper was 1.5 times the gape. The ore contained 20% material minus 4.0 cm. The bulk density of the rock was 1.75 t/m³ and the nip angle 22.8°. Determine: 1. Capacity of crusher 2. Power consumption if the work index of the material is 12.5 kWh/t 3. Operating speed 4. Minimum level at which the feed should be maintained in the feed-hopper.