Which term describes material used to fill underground voids created by mining activities?

Backfill refers to the material, which can be soil, rock, or a specially engineered substance, that is used to fill voids left by mining operations. This practice is essential for multiple reasons, including stabilizing underground surfaces, minimizing subsidence, and reducing environmental impacts. By refilling mined-out areas, backfill helps maintain the integrity of the surrounding rock structure and supports ongoing mining activities by providing a solid foundation for equipment and personnel.

Overburden is the layer of soil and rock that is removed to access the minerals beneath, while aggregate typically refers to a combination of materials, such as sand, gravel, or crushed stone, used in construction and civil engineering. Fill material can be a more general term that encompasses various types of materials used to fill, but backfill specifically indicates material used to refill the areas created by mining, making it the most accurate term in this context.