Data pertaining to a surface bench blast is given below:

Burden = 3.0 m

Sub-grade drilling = 1.0 m

Spacing = 4.0 m

Collar stemming = 4.0 m

Bench height = 10.0 m

Air decking length = 1.0 m

Density of rock = 2000 kg/m³

Linear charge concentration = 10 kg/m

The powder factor of the blast, in kg/tonne, is _____