Karangahape Station Construction
A Mitsui S200 roadheader was launched from the Mercury Lane shaft to excavate the first tunnel platform and two adits along the way before breaking through at the Beresford shaft. The tunnel stub (where the passing TBM will pick up excavation within the station) was excavated using a twin header on a 14T excavator.
The second roadheader, a Mitsui 300, was then used to overcut the tunnel and brattice was installed to block open sections of tunnel that would otherwise have resulted in air loss to create sections within the tunnel. Once brattice work was complete, the Mitsui 200 was launched in the second tunnel and the same extraction method is now being used as the roadheader progresses back toward Mercury Lane.
The urban location and construction method at Mercury Lane pose numerous space and noise constraints. To keep noise down and equipment out of sight, an acoustic shed houses all ventilation equipment at surface-level. The height of the mezzanine required the JMS-60-MES to be modified, so Grydale custom-designed the equipment to allow the exhaust silencer to be rotated 90 degrees (from the roof) to allow sufficient clearance.
Remote Service Support
Grydale has an in-house service and maintenance team, however restrictions on travel as a result of the COVID-19 pandemic meant our team needed to find a way to provide product service and support remotely, including the onsite commissioning of the dust collector and axial fan. This was effectively undertaken using live video support.
Local Spare Parts
Ventilation and dust extraction are key to providing a safe work environment, so keeping the dust collector operational throughout the excavation process is critical. To ensure there was a local supply of spare parts, Grydale delivered a 20ft shipping container with critical parts and service kits, including an extra set of filters, to the job site.
As of July 2021, the second roadheader is excavating the tunnel from Beresford Shaft to Mercury Lane at K-Road Station. The CRL project is scheduled to complete in 2024.