Vermeer Leveling the Hunter

CRAIG BATTEN, National Manager Mining Services at Vermeer reports on the excavation of the new Hunter Expressway.

A Vermeer Terrain Leveler is assisting with rock excavation on the $1.7 billion Hunter Expressway project that will cut travel times between Newcastle and Branxton by half an hour, and relieve congestion by taking up to 30,000 vehicles a day off the New England Highway. Completion is expected at the end of 2013 and the work has been let in two contracts:

• Eastern Section (F3 to Kurri Kurri), undertaken by the Hunter Expressway Alliance (Roads and Maritime Services, Thiess Pty Ltd, Parsons Brinckerhoff and Hyder Consulting), and
• Western Section (Kurri Kurri to Branxton), undertaken by Abigroup Contractors Pty Ltd under a design and construct contract.

The Vermeer T1255 Terrain Leveler is working on the Eastern Section, with its owner Trenching Systems Australia (TSA) being initially hired to excavate Cut 13.

The rock in the cut is slightly weathered massive sandstone with some bands of conglomerate, and hardness is 30-40 MPa. There are few defects. The shallow depth of the cut (less than 3 metres) ruled out blasting, while the rock was too hard for ripping. The production rate of around 40 -60 m3/hr is comparable to production rates expected of blasting and ripping in this type of rock, and the Terrain Leveler has fitted seamlessly into the earthworks programme.

The cut rock is taken directly to fill locations where it is used as upper zone (300mm depth) base material immediately beneath the designed pavement. The excavated material is watered before it is picked up and transported, to control the moisture level.

There was some experimentation in the method of pick-up and transport until a Caterpillar 615 elevating scraper was settled on as the best means of keeping the work area tidy and removing material at a constant rate.

A feature of the Vermeer Terrain Leveler is its ability to cut to close tolerances, with the ability to alter the depth of cut as well as the angle of the drum. This makes it an ideal machine to use with 3D GPS control. The
ability to vary the depth of the cut provides some control over the size of material produced, with deeper cuts producing smaller material.

As a result of its performance in Cut 13, a decision has been made to extend the use of the Terrain Leveler to base excavation in Cut 16. This cut has inter-bedded sandstones, siltstones and mudstones, with the rock being slightly weathered and having strength varying between 20 MPa and 50 MPa.

There are more defects than in Cut 13, with these typically occurring every 100-300 mm. This is a deeper cut than Cut 16 and blasting will be used, with the Terrain Leveler used to excavate to within 30 mm of the design level.

TSA is responsible for set-up and operation of the Terrain Leveler. The main adjustments required were a slower drum speed to better match the rock, and tweaks to the dust extraction system to increase its effectiveness. However the Terrain Leveler was basically productive from when it was put to work. Use of consumables is modest: around five picks are changed each day.

David Wheatley, Senior Project Engineer – Earthworks for the Hunter Expressway Alliance, believes that the biggest current limiting factor to wider use of Terrain Levelers in civil projects is their availability in the hands of subcontractors. Subject to availability, Wheatley said, “I would look at using this piece of plant in all cuttings as an option, especially at the base.”

Apart from applications in trimming to level and undertaking shallow cuts, Wheatley adds, “The Terrain Leveler could be the most productive way of mining a cut of any depth for other reasons, such as distance to sensitive receivers. Vibration and noise restrictions at these receivers may require the use of a Terrain Leveler over traditional methods of drill and blast or rock hammering.”

Vermeer Sales & Service’ National Manager Mining Services Craig Batt en believes that the supply issue is improving, stating, “Trenching Systems Australia has taken delivery of a second Terrain Leveler, which is a huge endorsement of their performance and their future.

“We have fielded other inquiries, and are confident that the size of the contracting fleet will increase. We also feel that the new T1655 (nearly twice the size of the T1255) has applications in civil construction as well as mining, and this could change the economics of using a Terrain Leveler significantly”.

For further information please contact Craig Batten – National Manager Mining Services
Phone: 1800 620 720
Mobile: 0419 667 133

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