Conveyors are used in quarries and mines to transport material of different grades either to a spoil tip or to another conveyor. The conveyors are usually externally sited and therefore must be covered to ensure that any dust created as a result of conveying is not blown away. The covers consist of a corrugated plastic material shaped as a lid over the conveyor. A plastic feed pipe is fitted to the side of the plastic cover and the spray nozzles are attached to feeder pipes at various points along the conveyor.
The number of nozzles fitted depends upon the type of quarry and the material being conveyed. Usually the nozzles are fitted every 4 or 5 metres. The type of nozzle fitted also depends upon the material being transported. They are usually hollow cone nozzles to avoid blockage problem, for example, fine dust needs a smaller volume and a smaller droplet size in the spray, larger materials require a wider angle of spray.
As the material travels along the conveyor the finer material drops to the bottom, so at the tip off point a flat spray nozzle is fitted underneath the conveyor to damp the fines and stop them blowing away. A second nozzle is required to spray on the tipping-off point. Water is normally drawn from a well or from a pond with a submerged pump. Filters are always fitted to the pipework either before or after the pump