Backfilling is the process of refilling an excavated hole and it also spelt back filling. In the mining business, this is a typical construction method. An essential component of underground mining operations is backfilling.
In addition to supporting the surrounding rock mass, the backfill material lowers the chance of surface level subsidence, minimises unnecessary ore dilution, and makes the mining site safer.
By putting backfill garbage underground, mining backfill can also be used to get rid of potentially dangerous waste and lessen its influence on the surface environment.
Backfill usually consists of tailings, or waste materials that are left over after the target mineral is mined.
The following materials are commonly used to backfill mines (Essential Guide to Backfilling in Mining Operations, n.d.):
- Cemented backfilling. Cement is poured over tailings and waste rock to help fill voids that need filling, thus binding the backfill together. This is particularly useful when low volumes of cement are needed to bind materials since cement can be very expensive in large quantities.
- Dry rock backfilling: dry rock consists of dried tailings, gravel, rock waste, or surface sand. This backfilling material is best used in cut and fill mining.
- Hydraulic sand backfilling: hydraulic sand is the result of separating out fine sand from tailings and using the coarser sand as backfill. The sands are hydraulically pumped into voids in mines. When deemed necessary, the sand can be mixed with binding agents.
- Paste backfilling: paste backfill is typically used in coal mines. Solid tailings are broken down and mixed with water, cementing materials, and fly ash, creating a coagulable paste that can be used for backfilling.
Reference
Essential Guide to Backfilling in Mining Operations. (n.d.). Retrieved May 13, 2025, from https://www.flyability.com/fr/blog/backfilling
