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PROCESSING SOLUTIONS Rinse and Recycle: Ore-washing System Cuts Process Costs for Russian Gold Producer This Hydro-Clean 700 unit and rinse screen were installed by Haver Screening Group to demonstrate their ability to efficiently remove sand and clay particles from gold ore at a mining operation in eastern Russia. The Haver Screening Group recently reported that an installation of its Hydro-Clean washing technology is helping a gold producer in eastern Russia increase production, reduce water consumption and minimize wear. The unnamed company currently uses a washing drum and two-bearing screen to separate sand and clay from ore, a method that has produced inade- quate washing results, causes excessive equipment wear, and consumes high volumes of water and energy. Working with the customer, HSG set up a Hydro- Clean 700 unit and rinse screen as a separate test operation to demonstrate it could successfully wash the opera- tion's three distinct products better than the current equipment. Each prod- uct has varying degrees of impurities, ranging from easy-to-wash to sticky material that is nearly impossible to clean with the current washing system. After installing this combination, the operation increased production from 5 metric tons per hour mt/h to 25 mt/h, reduced its water consump- tion by up to 70%, and reduced energy requirements by 30% for every ton of material, according to HSG. In prepara- tion for a large upgrade project, these positive results prompted the mine to include the Hydro-Clean in its plans for all future mineral washing. These two photos show the composition of material fed to the Hydro-Clean unit. www.e-mj.com Suited for Sand and Silt Removal The gold producer first contacted HSG about the Hydro-Clean in 2009 after see- ing impressive results at another gold operation using HSG equipment. The Hydro-Clean appealed to the producer because its current washing system—a traditional washing drum—was not removing enough sand and clay content to produce the required 2- to 120-mm gold product with clay content of less than 2%. Well-suited for use in clay- heavy material deposits, the Hydro-Clean employs high-pressure nozzles, rotating at 90 rpm, to spray mostly (90%) recy- cled water on the material at pressures up to 200 bar (2,900 psi) to remove silt and clay particles as small as 63 microns from mineral mixtures. While the high- pressure nozzles mounted at the top rotate and spray the material with water, turbulence in the drum creates addition- al scrubbing and abrasive forces that enhance the cleaning process to break up agglomerates and clean the particles of stubborn material. The Hydro-Clean also injects high-pressure streams of water into areas of the material (holes, cracks, etc.) that are difficult to reach with tradi- tional cleaning methods. A UME 1,200 mm x 4,500 mm screen then rinses away the loose sand and clay contaminants. The end result is a cleaner gold ore product with clay content less than 2%. Saving Water and Energy The Hydro-Clean, according to HSG, uses far less water and energy than the washing drum and two-bearing screen used by the producer, which consumes up to 13,000 l of water to wash just 1 Washed ore emerges on the conveyor. The Hydro-Clean technology allowed the operator to reduce its ore-wash- ing water requirements by 70%, along with significant energy savings per ton of processed material. JUNE 2012 • E&MJ; 151