Silos On The Move

The nine big red silos that have been a prominent part of the Mercury Lane landscape as part of Karangahape Station construction have moved.

The accompanying bentonite plant and the four-metre tall silos are now at the western end of Beresford Square next to the Hopetoun Alpha - and will be there for the next five months.

The plant creates and recycle bentonite slurry, which is a wet clay that helps with the creation of station walls, known as diaphragm walls (D-walls). A D-wall is a continuous wall constructed in the ground, typically to form an underground barrier or structure. 
 
The clay is pumped into the excavated area to keep ground water out, maintain positive pressure, and prevent the trench from collapsing until steel reinforced concrete can be added in its place. The bentonite is continuously pumped through the excavated area and back through the plant to screen out dirt and other material prior to re-use.

The bentonite will help the team create the first permanent elements of the Karangahape Station entrance at Beresford Square.