The MSP Joint Venture - McConnell Dowell, NC Lavaline and Parson Brinkerhoff - contracted to build Te Mihi has awarded supply of approximately 12,000m³ of concrete over the next two years to Firth with the first of the main pours beginning in September.

"We have completed some extremely large pours - 3 x 400m3 and 3 x 200m3 - for the foundations and slabs of the two steam turbines that are under construction," says Ian Kamo, Rotorua/Waikato Area Manager for Firth. "In one of the first weeks alone we supplied more than 900m3 to the site. The Taupo team has only been able to do this with the support of trucks from our Wellington, Taranaki, Hastings, Hamilton, Rotorua, Whakatane and Te Awamutu colleagues. Our teams are often starting before 3am and working through to 3pm."

Due to the 1.2m thickness of the slabs Firth designed specialised mixes to deal with the heat of hydration. Ian explains, "we have had to keep an eye on the water/cement ratio and the mixes included lots of flyash to keep the temperatures down due to the mass of the slab. We also used a 40mm aggregate for these mixes as opposed to a 19mm aggregate. The size of the aggregate helps to reduce the shrinkage and reduces cracking."

"Firth have done a great job for us so far," says Mike Buckland, Project Manager for MSP Joint Venture. "They are very responsive to our needs. John Hambling, Technical Engineer for Firth has had to design some very technical mixes to deal with construction on a geothermal site."

With some very large pours still to come for basement slabs and the 14.5m pedestal columns there will be a few more early starts yet for the team at Firth and the construction crews.

"We are fortunate to have very good suppliers on this project and Firth are certainly one of the valued players," adds Mike.