Filtered tailings can be a viable option for managing tailings disposal at mines. Some of the advantages of filtered tailings include: i) reduction in water consumption, as more process water can be recycled; ii) the filtered tailings can often be stacked (often referred as dry stack tailings) to reduce the footprint for tailings storage; and iii) the dry stack tailings can often be reclaimed concurrent with placement, thereby reducing reclamation costs. Filtered tailings have these advantages over slurry, thickened, and paste tailings as the filtration process used (either vacuum belt or mechanical presses) essentially advances the consolidation process (which can tens of years or more to achieve with traditional slurry disposal) to form an unsaturated cake. The filter cake often has a consistency of moist sand or silty sand, with geotechnical and hydraulic properties amenable to stacking and compaction. While thickened and paste tailings may be able to achieve beach slopes in the 3 to 6 percent range, dry stack tailings may be stacked with stable slopes in the 20 to plus-30 percent range, with compaction. This paper presents the primary geotechnical considerations for the design of dry stack facilities. The designs issues discussed in this paper include rate of stacking, stacking height, seepage/infiltration, and settlement. In addition, this paper addresses some common misconceptions regarding the geotechnical and hydraulic performance of dry stack tailings based on actual lab and field data.
展开▼
