Stabilizing and optimizing of back-fill material in mining by the use of mining waste. (BackFillStab)

Purpose and goal

The purpose was to find methods for modifying iron sands from primarily Swedish smelters to replace all, or some part, of the cement when mixed with sand for the use as a back-fill in mines. Optimum mixtures have been identified, which means that part of the cement can be replaced with modified slag with unchanged function. The goal achievement is good. Another aim was to establish close cooperation between Swedish and Chinese parties. Through collaboration established between LTU and BGRIMM, the goal has been met well. Collaboration continues. Visits by reseachers in both institutions

Expected results and effects

In cooperation between LTU and BGRIMM, methods for modifying iron sands have been established. Results show that the product can completely or partially replace cement when used with sand for back-fill in mines. Material was tested in laboratory and needed strength was achieved. Different mixtures was studied and strength determined. Optimal mixtures have been identified. Cost savings and CO2 reduction have been estimated. Collaboration between LTU and BGRIMM has resulted in several joint projects and studies. Collaboration continues. Exchange has taken place in both directions

Planned approach and implementation

Initial workshops with Swedish and Chinese partners. Opportunities for modification of iron sands were identified. Exchange of researchers between LTU and BGRIMM in both directions. Identified possibilities for modifying iron sands were tested in laboratory. Optimal method was identified. The slag´s use as a replacement for cement was tested in laboratory. Sand was mixed with different amounts of modified slag and cement. Strength was tested for different blends and optimal blend was identified. Tests in close collaboration with BGRIMM. Researcher exchange in both directions.