“However, the technology exists to effectively address this problem, both for import and export operations, by utilising the appropriate solution for each – regrettably, there is no one solution for all.” Environmental pollution by fugitive dust is a major issue for all ports handling dry bulk cargoes in general but cement clinker in particular, she says.“Uncontrolled loading and discharge creates a major dust nuisance, often leading to litigation and in extreme circumstances the closure of the facility.

“This problem has been further exacerbated by the introduction of unsuitable mobile harbour equipment based on both grab cranes and simple mobile belt conveyors.”

Mobile harbour cranes or ship cranes are frequently applied to the handling of bulk cargoes by grab, but require specialised hopper systems to limit dust pollution, says Aumund.

“Closed grabs improve the ship to shore material transfer over the ship’s rail but once the grab is opened on the shore side, dust is inevitably released into the atmosphere and must be controlled.” Aumund’s Eco-Hopper, a mobile grab hopper,  incorporates dust extraction equipment to minimise dust escape from the opening grabs. If required, it can be mounted on rails astride a central belt conveyor system used to transport the material from jetty to local storage at the port.

Typically discharge rates of 500 tonnes per hour per hopper can be achieved, subject to the grab crane performance, says the company.

The Eco-Hopper features “Flex-Flaps” which act as a non-return valve, allowing the material to fall through but preventing a large proportion of the displaced air from flowing upwards.

Multiple dust filters are provided around the hopper bowl, to extract and filter the dust-laden displaced air. The hopper bowl is maintained at a slight negative pressure, causing a net inward air flow through the Flex-Flaps.

Mobile harbour equipment is an attractive option for the port operator, with fast-track availability and reduced project costs, says Aumund; fully mobile integrated solutions offer real flexibility in that the equipment does not have to be tied to any particular berth or even port and can be easily relocated.

“However, when handling even moderately dusty materials, environmental protection standards remain as relevant with mobile equipment as they are with fixed dedicated systems and the purchaser must address these issues within the scope of the export project as a whole.”