Abstract: In order to understand the influence of flocculant and feed concentration on the perfor⁃ mance of full tailings backfill of a copper mine，research on the natural sedimentation and flocculation sedi⁃ mentation law of tailing slurry with different mass concentrations were carried out after analyzing density， particle size and chemical composition and other performance characteristics. Meanwhile，the performance analysis of field backfill was conducted. The results showed that with the increase of slurry concentration， the sedimentation rate decreases and the bottom flow concentration increases，and the maximum bottom flow concentration can reach 68% in the natural sedimentation. Flocculant can significantly improve the sedimentation rate of the full tailings. When the concentration of tailings slurry is 20%，the sedimentation rate of the full tailings increases by 4.7 times after adding flocculant ZYDY of 20 g/t. While the bottom flow concentration decreases by 6 percentage points. In flocculation sedimentation，the sedimentation rate of full tailings slurry decreases and the concentration of bottom flow increases，and the concentration of bot⁃ tom flow in flocculation sedimentation is 49% to 61% with the increase of feed concentration. The effective coring rate，integrity and effective sample of the natural sedimentation backfill are not as good as those of the flocculation sedimentation backfill，and the effective sample strength of the two kinds of backfill pro⁃ cesses all meet the strength requirements of the backfill.

Key words: full tailings, natural sedimentation, flocculation sedimentation, sedimentation rate, under? flow concentration, coring rate, backfill strength