A process of rigidifying mineral slurry residues from a mineral processing operation whilst retaining the fluidity of the material during transfer, in which the material comprises an aqueous liquid with dispersed particulate mineral solids that is transferred as a fluid to a deposition area, then allowed to stand and rigidify, characterised by combining with the material during transfer an effective rigidifying amount of an aqueous solution of a water-soluble polymer which is a dose of 10 grams to 10,000 grams per tonne of material solids, said water-soluble polymer having an intrinsic viscosity of at least 5 dl/g (measured in 1M NaCl at 25°C) and being selected from (i) water soluble anionic polymers formed from monomers selected from the group consisting of (meth)acrylic acid, allyl sulphonic acid and 2-acrylamido-2-methyl propane sulphonic acid as the free acids or salts thereof, optionally in combination with non-ionic co-monomers, selected from the group consisting of (meth)acrylamide, hydroxy alkyl esters of (meth)acrylic acid and N-vinyl pyrrolidone; (ii) water soluble non-ionic polymers formed from monomers selected from the group consisting of (meth) acrylamide, hydroxy alkyl esters of (meth) acrylic acid and N-vinyl pyrrolidone; (iii) water soluble cationic polymers formed from monomers selected from the group consisting of dimethyl amino ethyl (meth) acrylate - methyl chloride (DMAEA.MeCI) quaternary ammonium salt, diallyl dimethyl ammonium chloride (DADMAC), trimethyl amino propyl (meth) acrylamide chloride (ATPAC) optionally in combination with non-ionic co-monomers, selected from the group consisting of (meth) acrylamide, hydroxy alkyl esters of (meth) acrylic acid and N-vinyl pyrrolidone; (iv) water soluble natural polymers and semi-natural polymers selected from the groups consisting of starch, guar gum, dextran, carboxymethyl cellulose and hydroxyethyl cellulose. (v) water soluble amphoteric polymers. (i) water soluble anionic polymers formed from monomers selected from the group consisting of (meth)acrylic acid, allyl sulphonic acid and 2-acrylamido-2-methyl propane sulphonic acid as the free acids or salts thereof, optionally in combination with non-ionic co-monomers, selected from the group consisting of (meth)acrylamide, hydroxy alkyl esters of (meth)acrylic acid and N-vinyl pyrrolidone; (ii) water soluble non-ionic polymers formed from monomers selected from the group consisting of (meth) acrylamide, hydroxy alkyl esters of (meth) acrylic acid and N-vinyl pyrrolidone; (iii) water soluble cationic polymers formed from monomers selected from the group consisting of dimethyl amino ethyl (meth) acrylate - methyl chloride (DMAEA.MeCI) quaternary ammonium salt, diallyl dimethyl ammonium chloride (DADMAC), trimethyl amino propyl (meth) acrylamide chloride (ATPAC) optionally in combination with non-ionic co-monomers, selected from the group consisting of (meth) acrylamide, hydroxy alkyl esters of (meth) acrylic acid and N-vinyl pyrrolidone; (iv) water soluble natural polymers and semi-natural polymers selected from the groups consisting of starch, guar gum, dextran, carboxymethyl cellulose and hydroxyethyl cellulose. (v) water soluble amphoteric polymers.