COST-EFFECTIVE PUMPING OF COARSE MINERAL PRODUCTS USING FINE SANDS

Coarse mineral particles with sizes of up to 200 mm can be pumped ener gy-effectively together with sands (<1 mm) under nearly pseudohomogene ous conditions at volumetric solids concentrations of up to 40%. Recen t experimental results indicate that particles with sizer of 0.1-0.5 m m play an important role in reducing pipe wall friction. Experimental results in pipelines with diameters of up to 0.44 m have here been use d in a brief demonstration of industrial applications: integrated syst ems for waste rock transportation together with fine grained tailings, coarse mineral particle pumping from open-pit mines or to disposal ar eas with dry deposition and recirculation of water and fine particles. Experiments with a crushed rock product (20-38 mm) pumped at a volume tric concentration of 13% showed that the friction losses were reduced considerably by particle degradation during the circulation in the pi peline loop. Circulatory effects must therefore be carefully considere d when using coarse-particle loop results in the design of industrial once-through systems. (C) 1997 Elsevier Science S.A.