Abstract: With gold mine tailings in Sichuan Pingwu Dabaoshan and Portland cement as raw materials,the backfill materials with gold tailing were prepared using a one-step method. The effects of various cement / sand ratios and slurry concentrations on rheological properties,bleeding rate,mechanical property were studied. Using distilled water as the extraction agent,the pH,suspended matter,chemical oxygen demand(COD),ammonia nitrogen,total phosphorus and fluoride of the leaching solution were investigated for the influence of backfill materials on groundwater. The results show that the strength development of gold tailings filling material is mainly cement hydration,and the alkaline environment after cement hydration stimulates the hydration of tailings. With the decrease of cement sand ratio and the increase of slurry mass concentration,the fluidity becomes worse,the bleeding rate decreases,and the compressive strength decreases. The water quality of the leaching solution was all much less than the standard limits according to groundwater quality standards of GB/ T 14848—2017 without any secondary pollution. The efficacy coefficient method was used to score the nine indexes. It is believed that the system′s overall performance is optimal when the slurry mass concentration is 68% and the cement-sand ratio is 1 ∶6. The microstructure of the backfill material was dominated by C-S-H gel resulting in good mechanical properties. 

Key words: gold tailings,fluidity,compressive strength,the water quality analysis,efficacy coefficient method