Abstract:

The purposes with regard to all underground voids filled with tailings are categorized into three aspects such as improvement safety issues (i.e. ground control), increasing economics (i.e. enhancing ore recovery rate), and environmental requirements (i.e. reduction acid water drainage). The types of backfill technologies include slurry backfill, paste fill and rockfill. The first two types of the backfill are also called as hydro-backfill, and rockfill is called as dried-backfill; all of which are applied to Canadian mines. UCS (uniaxial compressive strength) and permeability are critical parameters for slurry backfill in minefill applications, which affect on the quality of underground minefill. On the one hand, cement needs to be added into the slurry backfill materials to improve the strength of the fill materials; the huge tonnages of which are used for minefill and cement takes up the large component of mine fill costs; on the other hand, the coarse solid recovery used for backfill materials is classified from underflow of hydrocyclones, meanwhile fine parts flow out through overflow of the hydrocyclones to the tailings pool; sometime the backfill tailings of the mines are deficit and sand needs to be bought, which is mixed up with the tailings to be filled into the voids of underground. It is the concernful research issues for mine industry how to reduce the amount of cement added into backfill materials and improve the solid recovery particularly fine parts from underflow of the hydrocyclones in order to save the backfill costs. The effects of flocculant-assistance on UCS of tailings for slurry backfill are investigated. The results of the experiments indicate that the strength of tailings could be improved largely by the flocculant-assistance; moreover, the maximum strengths of backfill with flocculant-assistance are achieved at the optimization value of flocculant dosage, whereas the over-dosage of flocculant could have an adverse effect.

Key words: flocculant, slurry backfill, tailings, uniaxial compressive strength