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Investigation of Solids Content Influence on High Density Slurries Niobium Fine Tailings Disposal

Tailings and Mine Waste Conference (2023 : Vancouver, B.C.); University of British Columbia. Norman B. Keevil Institute of Mining Engineering

A new tailings dam facility is being designed for niobium ore tailings, which will involve the disposal of a high-density thickened slurry instead of the currently employed diluted slurry. Several advantages were identified to dewater before disposal, including high water recovery, low mobility of tailings, and avoiding particle segregation. Tailings disposal, when carried out in the form of diluted slurry in an underwater disposal structure, has a tendency for particle size segregation, wherein coarse particles tend to settle near the deposition point and the finer particles are carried by the water flux to more distant regions. Segregation causes a loss of reservoir capacity due to the existence of empty spaces between the coarse particles. The objective of this work was to evaluate what solids content is necessary to reach the level of a nonsegregable slurry, and the estimated gain of slurry density. Physical and chemical characterization of the material and simulation tests of tailings disposal were performed in pilot-scale flume tests with different solids content (60 to 70%). Nine flume samples were collected to measure particle size distribution, and the solids content over the course of 9 days, as well as water liberation, were also measured. The results indicated that there is no segregation of particles in high density slurry. Yield stress ranged from 13.1 Pa with 61.8% solids, and reached 88.3 Pa with 69.7% solids. All the conditions showed water liberation, which can reach 10% of the total water in the tailings. The solids content measured indicated that there was water loss due to evaporation after disposal. The disposal angle obtained was 0.98% for the lower solids content and 2.90% for the highest one. The gain of pulp density was 75%, considering that at least 50 Pa was the project target, as well as an increase of 74.9% in density, from 1.156 (18% solids) to 2.022 t/m³ (67.4% solids), which can promote a gain of capacity in the reservoir.

Text

2023-12-08

Attribution-NonCommercialShareAlike 4.0 International

http://hdl.handle.net/2429/86835

Unreviewed

http://creativecommons.org/licenses/by-nc-sa/4.0/