To address technical issues such as segregation,layering,drainage,and poor filling body quality in the graded tailings backfill at Sanshandao Gold Mine,the fundamental properties of tailings and cementitious materials were analyzed.Using curing age,cement-sand ratio,and slurry concentration as study variables,the extensibility of backfill slurry and the uniaxial compressive strength of the filling body were used as reference indices to investigate the strength characteristics of high-concentration backfill.Experimental results show that slurry concentration is the primary factor affecting the spread of backfill slurry,while the cement-sand ratio has a smaller influence.However,curing age and the cement-sand ratio are the main factors affecting filling body quality,with slurry concentration being secondary.Based on the mining methods of the mine,technical parameters were proposed to meet the backfill requirements.