A double ended ranging drum shearer operates in a longwall retreating panel. The following data are provided:

• Face length: $200\ \text{m}$
• Average cutting speed: $1.5\ \text{m/min}$
• Web depth: $0.6\ \text{m}$
• Average flitting speed: $4.0\ \text{m/min}$
• Cutting height: $2.5\ \text{m}$
• Number of shifts/day: $3$
• Density of coal: $1.4\ \text{tonne/m}^3$