## 1 Introduction  
Gold mine tailings have a large output and high processing costs. At present, the existing mine tailings storage stocks are limited, and the cost of building a new tailings pond is relatively high. As a result, tailings discharge and utilization have become key issues restricting mine development [1]. The backfilling mining process using tailings as backfilling aggregate is not only conducive to safe mine mining but also consumes a large number of tailings, which can achieve the effect of full utilization of tailings [2]. Due to the difference in geological conditions and different mining processes, the ore grinding fineness of different mines differs. On the other hand, the mining grade of gold ore is gradually reduced, and the mining depth is continuously increased. To ensure the full separation of gold-containing substances, the ore must be ground down, which is bound to produce more medium and fine tailings. At present, some gold mines at home and abroad have made full use of backfilling with medium and fine tailings [3; 4; 5; 6; 7; 8]. However, changes in the fineness of tailings will inevitably lead to changes in the density of tailings, fluidity of backfilling slurry and strength of backfilling body [9; 10]. To achieve a good backfilling effect and ensure mine production, the backfilling process and cementitious materials also need to be adjusted. [PERSON] et al. [11; 12] studied the effect of the initial sulfate content of a cemented paste composed of tailings on the interfacial behavior and resistance. [PERSON] et al. [13] studied the creep hardening characteristics of the backfilling paste utilizing a uniaxial compression test and concluded that backfilling paste will experience macro hardening during the creep process, which is of great significance for maintaining the long-term stability of the backfilling body and improving the backfilling effect. [PERSON] et al. [14] studied the tailing paste backfilling and obtained the comprehensive effects of initial sulfate content and curing temperature on tailing paste backfilling. [PERSON] et al. [15] systematically studied the effects of factors such as sand content, water-binder ratio, and slurry mass fraction on the slump and elastic modulus of paste materials, and successfully prepared paste materials with high strength and excellent pump ability. [PERSON] et al. [16; 17] used the uniaxial compression test to carry out relevant research on two different lime sand ratio combinations. [PERSON] et al. [18] analyzed and studied the settlement of tailings backfill and found that the pore water and particle movement in the sedimentation process were very similar to the normal shrinkage process. [PERSON] et al. [19] established the technical system of backfilling goat with high-concentration paste materials. The research results show that backfilling mining can effectively control the movement of rock strata and reduce surface subsidence significantly. They also showed that the higher the strength of the backfilling body, the better the effect of reducing subsidence. [PERSON] et al. [20] took the tailings backfilling material of underground mines as the research object, combined experimental research with theoretical analysis, used an R/S rheometer and rock mechanics testing machine to conduct experimental research on the rheological properties of the backfilling material slurry, and introduced Panastasiou viscoplastic fluid model to characterize the viscosity and shear stress change process of the tailings backfilling material slurry. [PERSON] [21] applied the BackfillICAD model to determine the backfilling time of zinc ore and lead ore and conducted indoor tests on the backfill. In the laboratory tests, the content of grains below 0.1 mm, the washability, water permeability, and compressibility of the backfilling mixture was determined. [PERSON] et al.