Guiding roadheaders for WestConnex 22 Jun 2017

VMT has won the largest order in its history to provide 57 navigation systems for roadheaders and bolter rigs engaged on the WestConnex highway tunnel project in Sydney, Australia. Orders are placed by the contractors progressing two major stages of project employing 36 roadheaders and 21 rock bolting rigs to excavate the competent and favourable Sydney sandstone.

VMT TUnIS navigation systems to guide roadheaders

Through its Australian subsidiary VTG, VMT will supply its TUnIS navigation equipment to ensure the roadheaders excavate the design tunnel profile and bolters position their tunnel support accurately. The systems assist the operations of the units to position the machines accurately within the tunnel headings to excavate the face and install the patterns of rockbolt support according to design requirements. The systems will also integrate collected information with the online monitoring software based in the construction site offices to process positional and profile data, power consumption, hydraulic pressures and other operational factors that can be used to monitor machine performance. The order includes teams of permanent on-site service technicians for system commissioning and support, and for the training of surveyors, site engineers and system operators.

The path of the roadheader cutter boom in relation to the face and the pre-designed profile of the tunnel cross-section will also be collected for post-excavation analysis to correlate cutter effectiveness in relation to the local geology and to ensure the accuracy of the roadheader cut to the required tunnel profile. The systems will also support training of roadheader and bolter operators.

VMT systems collect performance data for analysis

“The WestConnex orders combined result in one of the largest single navigation system supply commitments VMT has ever had, both in terms of units provided, value for a single client and commitment in terms of VMT manpower, ” said Alexander Höfer, VMT Product Manager for the projects. “Our engineers have worked tirelessly to ensure that the navigation systems are physically ready to go and meet the stringent requirements set out by the WestConnex delivery team.”

WestConnex stage 2 New M5 will include twin tunnels running from Beverly Hills to St Peters. Stage 2 M5N is due for completion in 2019 and will also be excavated using roadheader equipment. Each mainline tunnel will comprise 9km in length with 75 cross passages, giving a total tunnelled length of 19km.

Roadheader excavation of the Hawkesbury sandstone is selected for the WestConnex Stage 1B M4E and Stage 2 M5N contractsdue to access limitations and to reduce the impact of construction on the surrounding urban area and its population.

Accurate excavation and rockbolt support of the underground highway

The construction plan for the WestConnex Stage 1B M4E contract by the Leighton/John Holland/Samsung C&T JV includes excavation of twin 5.5 km long tunnels with three lanes in each direction and 50 cross-over and cross-passage connecting tunnels, a total tunnelling effort of some 14km, from four construction sites using 20 roadheaders, including eight new Mitsui SLB300 units from Japan, three previously used Mitsui SLB300 AU units, five Sandvik MT720 and MT520 units and a further Mitsui S200 unit together with 11 Robodrill bolting rigs.

Equipment on the WestConnex Stage 2 M5N contract to excavate 9km of twin-tube, three-lane road tunnels and 75 cross passages, for a total of 19km by the CPB/Dragados/Samsung C&T JV, includes 16 roadheaders – six Sandvik MT720 units and 10 Mitsui SLB300 units – and 10 Robodrill bolters.

The challenge for VMT is to deliver, commission and support the 57 navigation systems between May 2016 and 2019 when excavation of the two sections is due to be complete.

The VMT navigation system is used to position the bolter at the correct location. The machine then installs the bolting pattern with the operator having the knowledge that the machine body is located precisely, which means that as the bolts are installed they too are positioned exactly where planned.