Key Points of Material Selection and Construction for Underground Cemented Backfill

Cemented backfilling is an important mining technology for goaf treatment, ground pressure control and solid waste disposal. The selection of backfill materials directly determines the strength, fluidity and stability of the backfill body. Common aggregate materials include tailings, crushed rock and river sand; cementitious materials are mainly cement, and auxiliary additives such as water reducing agent and retarder can be added to adjust slurry performance.

Material proportion test is essential before formal construction. The matching concentration and cement-sand ratio should meet the design strength requirement while guaranteeing pipeline transportation performance. Too high concentration easily causes pipeline blockage; too low concentration leads to segregation and low strength of the backfill mass.

The standard construction process covers material preparation, slurry mixing, pipeline conveying, goaf pouring, maintenance and quality inspection. Pipeline layout needs to avoid sharp bends to reduce abrasion. On-site monitoring indexes include slurry concentration, flow rate and backfill body curing strength. Standardized material selection and construction operation can prevent backfill collapse, pipeline blockage and other risks, ensuring safe and continuous mining.