Process for flocculating and dewatering oil sand mature fine tailings

A process for producing bitumen from oil sands fine tailings, the process comprising:

• retrieving oil sands fine tailings from a tailings pond;
• subjecting the oil sands fine tailings to separation to produce recovered bitumen and a bitumen-depleted fine tailings;
• treating the bitumen-depleted fine tailings to separate water and fine solids contained therein, wherein the treating comprises:
• adding a flocculant solution comprising an effective amount of flocculation reagent in-line into a flow of the bitumen-depleted fine tailings to cause dispersion of the flocculation reagent and build-up of flocs to form flocculated fine tailings;
• transporting the flocculated fine tailings in-line and subjecting the flocculated fine tailings to in-line shear conditioning to increase a yield stress thereof to a peak yield stress and produce an in-line flow of a gel stage tailings material;
• subjecting the gel stage tailings material to further in-line shear conditioning to reduce the yield stress from the peak yield stress and produce an in-line flow of an ungelled flocculated tailings material;
• discharging the ungelled flocculated tailings material from a pipeline discharge outlet;
• and
• allowing the discharged ungelled flocculated tailings material to undergo solid-liquid separation wherein water separates from flocculated fine solids.

A process for producing a mined product from mined ore, the process comprising:

• forming an aqueous slurry comprising the ore;
• subjecting the aqueous slurry to separation to produce the mined product and fine tailings comprising water and fine solids;
• and
• treating the fine tailings to separate water and fine solids contained therein, wherein the treating comprises:
• adding a flocculant solution comprising an effective amount of flocculation reagent in-line into a flow of the fine tailings to cause dispersion of the flocculation reagent and build-up of flocs to form flocculated fine tailings;
• transporting the flocculated fine tailings in-line and subjecting the flocculated fine tailings to in-line shear conditioning to increase a yield stress thereof to a peak yield stress and produce an in-line flow of a gel stage tailings material;
• subjecting the gel stage tailings material to further in-line shear conditioning to reduce the yield stress from the peak yield stress and produce an in-line flow of an ungelled flocculated tailings material;
• discharging the ungelled flocculated tailings material from a pipeline discharge outlet;
• allowing the discharged ungelled flocculated tailings material to undergo solid-liquid separation wherein water separates from flocculated fine solids.

A method for selecting a polymer flocculant for use in dewatering fine tailings, comprising:

• dispersing polymer flocculant samples into corresponding fine tailings samples under first shear conditions to form corresponding dispersed flocculation matrix samples;
• conditioning each of the dispersed flocculation matrix samples under second shear conditions to form conditioned samples, wherein the second shear conditions provide a lower shear rate than the first shear conditions;
• determining a corresponding water-release response of each of the conditioned samples;
• and
• selecting a polymer flocculant corresponding to the polymer flocculant sample enabling the conditioned sample to have a selected water-release response based on the corresponding water-release response of each of the conditioned samples;
• wherein the fine tailings samples comprise solids in a concentration of between about 15 wt % and about 45 wt %.