Output torque required to run sand mixer..

Hello Dear Friends !!!!


I want to design gearbox for sand mixer.But I want to calculate output torque require to run mixer. Please search image on google for getting idea about the sand mixer. According to my calculation it is coming out to be 2743.2 Nm.
If not then how to find it ???

Data:
Capacity of mixer-300 kg
Diameter of mixer (or rotor)- 45 inch
Coefficient of friction between sand and rotor taken-0.4

 

It's coming about 1345.53Nm

 

The required output torque depends on the number of vanes in the rotor, their profile and angle among other criteria.