The scaling factors are defined as:

where:
- the
subscript refers to the original mill from which
was derived
- the
subscript refers to the mill being simulated (scaled)
are scaling exponents,
,
, and 
The Work Index scaling factor,
, is retained from the Perfect Mixing ball mill model, where
is the Bond Ball Work Index value of the ore (kWh/t).
The model user may optionally change the values of
to suit specific test work results or operating data.