Effective dust control in large-scale mine conveying

Sandvik’s HX410 electrostatic dust suppression system will take on the challenge of transfer point dust suppression for RWE Power in Germany. The customer will evaluate the HX410 on a conveyor that transports lignite and overburden in the Garzweiler open-pit mine. The conveyor has a capacity up to 37,500 t/h at a belt speed of 7.5 m/s (25 ft/s) and a belt width of 2,800 mm.

Until now, RWE Power AG has used primarily water-sprinklers to reduce the dust to acceptable levels. At a transfer point, RWE Power cannot use water because of the coal-online analysis system installed there. One double HX410 will be installed on the upstream conveyor and a second double HX410 on the downstream conveyor. As the Sandvik HX410 has already proven its effectiveness and reliability in more than 200 applications, RWE Power decided to give it a chance to prove its abilities in the most demanding environment.

The system is ionisation-based and has been designed to bind dust where it is formed. It is a simple system with very low operating and maintenance costs, offering many benefits in comparison to conventional ‘suction-through-filter’ or water-based systems. It is suitable for retrofits or installations on new conveyor systems. The HX410 ensures that chutes, loading points and transfer points don’t generate unacceptable dust emissions. Without proper dust control, each transfer point could generate more air-borne dust that eventually spreads all over the conveyor area. In most applications, a single HX410 is installed right after the chute on top of the belt.

Basically there are two different standard sizes available. The first is for belt widths 400 to 650 mm and the second for belt widths 800 to 1,400 mm. For wider belts, custom-made constructions can be offered by Sandvik. The power requirement for a standard system is below 500 W and maintenance time is less than 1 hour/month. The system picks up particles in the range of 0.01 to 100 µm. The efficiency for an average particle size of 5 µm is always above 90%.