Civil Construction Projects

• Candys Bend To Starvation Point Alignment 2001

  ­­Arthurs Pass NZ - (Sub-Contracted to Fulton Hogan Ltd)
  

  Project Manager – Lyell McMillan (100% tenure)­
  ­Site­ Manager – Jaron McMillan (100% tenure)
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  McMillan SDS were contracted to construct large diameter bearing piles and micro piles for the Cantilever Half Bridge and Rock Shelter structures.  Piles were installed through large boulders and rock using under-reaming DTH hammer and Dual Rotary methods.  Followed by 120no. 200mm diameter micro piles to 18m, and 15 no. 150mm diameter raking tension anchors to 18m through an active scree slope using concentrix methods, as part the Upgrade of State Highway 73.  In challenging conditions over 2,000 metres of drilling were completed during the 2 week road closure. This was made possible by careful co-ordination and project management to manage three drill rigs working 24 hours per day in continuous operation.

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• Matahina Dam Stregthening Project 1997

  ­­Matahina Whakatane NZ (sub contractor to Thiess Contractors Pty Ltd)
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  Project Manager – Lyell McMillan (100% tenure)­
  ­Site Manager – Kerry Mehlhopt (100% tenure)
  

  McMillan SDS were awarded the sub-contract for the drilling and de-watering components of the Matahina Dam Strengthening Project.  The timely completion of the de-watering phase was extremely important as it was a critical path item for the main strengthening works.  The contract consisted of constructing several 400NB de-watering bores to depths of 50m though highly jointed Ignimbrite (similar to that underlying Arapuni Dam).  The project involved an initial phase of test drilling and de-watering followed by design refinement and then the final construction.
  During construction, voided joints and shear zones unlike those encountered during test drilling introduced serious complications.  The Ignimbrite joints were dipping across the hole alignment and blocks were dislodged during drilling and jamming both the drill bit and casing.  Some joints were in-filled with fine to medium grained gravel and caused complications with loss of drilling circulation and limited cutting returns.  A number of holes also encountered significant quantities of water under partial reservoir pressures.
  Our under-reaming DTH system and Dual R­otary rig had sufficient capacity for our operators to adapt to the conditions and overcome these complications.  Production was hampered initially however once the drilling methodologies were refined, production was accelerated and deadlines achieved with ease.
  A total of 14 de-watering bores were constructed (including screen placement, filter pack and casing withdrawal) in 30 days, equating to approximately 630m of drilling.  In addition to this, 20 deep inclinometers were constructed through the dam embankment to monitor movements during and after construction.  These inclinometers were required to penetrate through the embankment sub vertical chimney and blanket drains.
  During all drilling works the dam reservoir and powerhouse was under normal operation albeit with a much lowered reservoir level.­
  

  ­Client referees and contact details:
  John Leckie, Project Manager, Thiess Contractors +61 7 327 58500
  John Ray, Senior Estimator, Thiess Contractors +61 7 327 58500
  
  
  

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