Geothermal Projects

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  OPEN LOOP SYSTEMS - University of Canterbury Air-Conditioning Project 2002

  Location:               Christchurch
  Project Manager:   Iain Haycock (100% tenure)
  Site Manager:        ­Harley Winchester (50% tenure)

  McMillan SDS was successful in tendering for the construction of the abstraction and re-injection bores for the University of Canterbury Air conditioning Project.

  The works consisted of constructing a 300NB abstraction bore to a depth of 200mbgl and two 300NB re-injection bores to 60mbgl. The positioning of the bores close to large  multi-storey buildings, the presence of artesian aquifers, stringent environmental conditions and university activities required careful consideration during construction. Precautions included installing pre-collars to isolate foundation vibrations during drilling and pressure grouting at depth to contain the potentially high artesian and re-injection pressures. Rotary and Cable Tool methods were adopted for this project given the site constraints and potential for above ground artesian aquifers.

  Considerable attention was placed on the removal of discoloured water during the construction phase and the contract allowed for 1,000m3 of water to be transported offsite at considerable expense. To avoid this cost, McMillan SDS successfully constructed and operated a temporary 300m3 settlement and filter tank system to treat all water prior to discharge into Okeover Stream, negating the need for offsite disposal.

  The contract was completed during the University Christmas vacation on time and on budget. The abstraction bore now delivers cool water (approximately 14 degrees Celcius) from a deep aquifer to the air conditioning plant prior to re-injection into a shallow aquifer via the re-injection bores.

  Referees
  David Monkman, Senior Environmental Engineer, OPUS International – tel (03) 363 5400
  Rob Oudshoorn, Works & Service Engineer, University of Canterbury – tel (03) 348 0873

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  CLOSED LOOP SYSTEMS - New House Heating & Cooling - Loop Road

  Location:              Loop Road, Queenstown, New Zealand
  Client:                  The Central Heating Company Ltd

  McMillan SDS were contracted to drill 3 x 100m deep at 150mm diameter bores, assit with loop installation, and conduct the loop grouting for a new house being built on the shores of Lake Wakatipu. The project had limited access, and the upper 6-12m of the ground encountererd was soft silts and gravels that required temporary casing to be installed. We selected out HD180 twin rotary rig for the contract, and successfully completed the contract on time and budget despite fractured rock and significant ground water being encountered.

  Referee
  Albie George from The Central Heating Company Ltd – tel 021 259 1977