To assess the quality of separation processes Helfricht (Helfricht,
1966) introduced a parameter B. This parameter is the ratio of an
area representing the achieved separation and an area representing
the theoretical limit (total liberation of valuables) in a plot of valuables
recovery versus mass recovery (Mayer diagram). Helfricht
was aware of a dependency of the parameter B to the feed grade
which causes variations in the calculation of B having the same
upgrading curve for varying feed grades. To overcome this problem,
Tolke (Tolke, 1970) recommends the plot of valuables recovery
versus gangue recovery (Fuerstenau diagram).