The results of an experimental research on dewatering of dump suspensionfrom the DECANTER centrifuge are presented in this paper. The suspension was taken from one of mines of the Jastrzębska Spółka Węglowa. This research allowed one to determine so called filtration parameters needed for the modeling of pressure filtration with cake compression. Some physical properties (density, mass fractions, moisture content, porosity, resistance of filter medium) as well as the kinetic constant coefficients (K and K') were concerned. The data was collected for the original suspension, i.e. liquid from the DECANTER centrifuge, and for the suspension with an addition of Magnafloc 919, flocculant used for flotoconcentrate, in the amount range between 10÷80 g/1 Mg of dry product, while the used dosage is 30 g/1 Mg. It was found that the addition of flocculant caused the increase of cake porosity and cake compressibility coefficient calculated according to the Tiller and Leu equation. Simultaneously, in small extends, the addition of flocculant resulted in increased cake's moisture content after the pressure filtration which is an unfavorable effect. On the other hand, it increased the constant kinetic coefficients K and K' in comparable conditions, enlarged mean arithmetic diameter of grains and accelerated the sedimentation process. The dosage of 30 g/1 Mg used by the maintenance personnel appears to be correct as well as the used filter cloth PT 912. One of the most interesting conclusion from this work is that the cake moisture content was lower after the pressure filtration than after the centrifuge filtration - this observation applies to the original dump suspension as well as to the one with the addition of flocculant. It is worth to emphasize that in case of the flocculant addition between 10÷30 g/1 Mg, Magnafloc 919 significantly influenced filtration properties of dump suspension. In case of the addition above 30 g/1 Mg that influence became very weak, therefore the application of the excessive addition is pointless from thetechnical point of view. The comparison of filtration parameters for dump suspension without and with the addition of flocculant suggests that there should not be any operating difficulties with the filtration process after a change of dewatering technology based on the usage of a settling tank for the dump suspension, recirculation of clear liquid and mixing of sludge with flotoconcentrate. One of advantages of this solution is the water - sludge circulation closure but it is connected with a greater DECANTER centrifuge load or with the addition of a supplementary centrifuge to the system.