The existing clinker ship unloading hopper was a standard grizzly design that was connected to a portable hire dust collector unit. During ship unloading using 30 tonne grabs, excessive dust was generated and was escaping from the hopper. This was due to the hired dust collector not being able to provide the large amount of extraction air required with an open mesh grizzly design.
There were three hoppers requiring dust extraction and these needed to be removed from the wharf between unloading operations. The truck loading that occurs simultaneously to the unloading was working well but was found to be using more air than necessary.
Luehr was awarded the contract to upgrade the standard grizzly mesh to the Luehr Louver design, which substantially reduces the open area and therefore the amount of extraction air required. To further assist in keeping the capital cost of the three dust collectors to a minimum, the amount of air used for the truck unloaders was reduced. Three mobile dust collectors with horizontally mounted oval bags were supplied with hydrophobic and fire retardant fabric to cope with the 95% humidity and the fact that the clinker was coming off the ship red hot.
The three dust collectors were delivered on time and have performed well. Even with the hydroscopic nature of the cement clinker and the high humidity of the Darwin climate, the dust cake release from the hydrophobic bags has proven very successful. This keeps the filter pressure drop and therefore the running costs low.