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 inadequate 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 operation’s three distinct products better than the current equipment. Each product 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 consumption by up to 70%, and reduced energy requirements by 30% for every ton of material, according to HSG. In preparation for a large upgrade project, these positive results prompted the mine to include the Hydro-Clean in its plans for all future mineral washing.

Suited for Sand and Silt Removal
The gold producer first contacted HSG about the Hydro-Clean in 2009 after seeing 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%) recycled 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 additional 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 traditional 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 ton of material. With the Hydro-Clean and rinse screen, the producer uses a maximum 4,000 l of water per ton, reducing the operation’s water consumption by up to 70%. In addition to water savings, the Hydro-Clean 700 saves up to 1.8 kW of energy for every ton of cleaned material when compared with the washing drum system.

HSG also noted that the Hydro-Clean’s compact size and lighter weight keep overall operating and structural costs considerably lower than with traditional washing systems—which also require more equipment and a greater footprint. In addition, the Haver unit experiences little wear with a low-maintenance design that allows for simple replacement of the few standard components that are subject to wear.

Following its initial success with the Hydro-Clean 700 test unit, the producer plans to authorize an investment program that will allow the installation of a larger washing operation with several HSG Hydro-Clean 1000 units. This operation would be capable of washing up to 4 million tons of auriferous ore each year.