Two applications of this PDE earlier described by Berres et al. (2010) and Usher et al. (2013) are compared for their utility in determining material properties for process modelling. For the first method, the constitutive functions are given in parametric form; the parameters are identified by solving an inverse problem through an optimisation routine. The gel point turns out to be a highly sensitive parameter which induces a natural ill-posedness. By the second method, the raw measurement data is used to characterise material property values at a number of solids concentrations. These data can then be fitted to determine parameters for constitutive functions. Both methods deliver functions for the phenomenological description of mine water dewatering.