SH2 Muldoon’s Corner upgrade – Opus (Oct/Nov 2007)
Muldoon’s Corner is a difficult section of State Highway 2 which needed realignment. It is located near the summit of the narrow and winding Rimutaka Hill Rd and features tight corners, no shoulder and near vertical faces above and below the road. It is also frequently closed due to extreme wind conditions, making work on site difficult.
As part of the planned realignment design our client, Opus International Consultants, needed information from several cored boreholes to be drilled in the middle of the traffic lane. Further holes were required below the road at the base of some of the retaining walls and also on the spurs immediately above the road.
Complicating factors and solutions
The bore holes on the road required that SH2 to be reduced to one lane each day and the rig moved onto the hole in the morning to work before moving off in the afternoon to allow the lane to be reopened in time for peak traffic flows. At the same time a number of other holes were drilled across the site by our light weight rig, which was craned into position onto platforms below the road to carry out a programme of cored boreholes. During this time Griffiths Drilling were also carrying out trial pit investigations by excavator and providing multiple lane closures to allow the client to conduct such things as mapping of rock faces along the road and seismic surveys.
The programme culminated with the boreholes drilled on the spurs above the road. For this stage a drilling rig was carried into place by helicopter as the only access to site is by foot and using ladders. These holes were also the deepest on the project.