Fluidization technique for mine backfill with slurry of high density

Fill placement using a very concentrated slurry for underground mines has been recognized as a favorable approach to improve backfill quality and economy. For this reason much effort has been devoted to preparation of high density slurry. This paper introduces the fluidization technique as a more effective and economic technology for producing tailing slurry of a high density and describes the fluidization mechanism, experimental system and results obtained during backfill. Test runs were carried out both in the laboratory and at a mine site with tailings of different size, which were allowed to settle down in a silo. A water jet was used to disperse solid particles and keep them in suspension and flowable under the action of gravity. The main factors affecting slurry density are fluid velocity, pressure and discharge. The technique introduced here has been used in backfill preparation and the density of slurry formed by fluidization has reached 75–80% solids by weight.