Iranians tunnel to water nuts

Calls are imminent for an international finance, design and build tender for 53.24km of 3.7m diameter water diversion tunnels in central Iran.

The client, the Rafsanjan Development Organisation (RDO) needs to transfer water from the Sulakan river to Rafsanjan to aid the irrigation of pistachio crops, carrying on a 2,500 year old tradition of water supply tunnel construction in the region.

The project also consists of five adits totalling 10.5km for ventilation, dewatering and demobilisation, as well as a storage dam and transmission pipeline. Amir Farajiazad of Mahab Ghodss, the client's initial phase designer, told T&TI that there were several financing offers from Asian and European banks. Local state banks have also backed the project.

He added that talks had taken place with selected contractors from Asia, Europe and South America who seemed capable of doing the job, but as it was an open tender, anyone was free to join the bidding.

The project management team is a proposed committee formed from the RDO, Mahab Ghodss and a third party consultant. During the construction phase, Mahab Ghodss will provide supervision for the client.

The selected methodology is fully mechanised, using three double shielded tunnel boring machines, each scheduled to advance 18m per day, based upon a 26 day month.

The programme anticipates TBM 1 will bore 10.7km before being overhauled and excavating a further 10.1km; TBM 2 will be overhauled after 8.94km before continuing for a further 8.3km; and TBM 3 will excavate a total of 15.2km, with an overhaul after 7.4km.

Farajiazad explained how the advance rates would be settled with the contractor by way of a penalty/bonus scheme linked to actual performance. He also said that at least two of the adits would be excavated with roadheaders at 3m per day.

The project cost is estimated at US$150M, with a 72 month construction period, including 10 months for design and site investigation. It is hoped that construction could begin nine months after the contract award, which is likely to be around Q2 this year.

Mahad Ghodss is also involved in consultancy and supervision for several similar projects in Iran. These include the 20.8km Gavoshan tunnel and the 23km Kohrang tunnel.

The 63km long Kerman tunnel contract has recently been awarded to Östu Stettin as technical co-leader with Jäger Bau, Seli and Iran Arvin, with TBMs due to begin work Q4 2004. Other projects are currently being considered such as the Great Sirvan project, which includes over 100km of tunnelling.