The contract, worth over £4m (US$5 million), is to deliver the geotechnical work associated with the intermediate shaft at Lockwood Beck, which will provide access to the tunnel that will contain the Mineral Transport System.

Bachy Soletanche are currently on site preparing to install a secant wall to form the launch chamber from which a specialist mining contractor will sink the intermediate shaft. The secant wall, consisting of 44 rotary bored piles with a diameter of 1,200mm, will be drilled to a depth of 20m.

Following the completion of the wall, Bachy Soletanche's Specialist Geotechnics division will construct a grout curtain to help facilitate the excavation of the intermediate shaft. The low permeable barrier, commencing 15m below the ground level, will be installed to a depth of 160m, forming a ‘dry shaft' below the secant wall.

"Our expertise and experience of delivering challenging projects, combining both piling and grouting, has been recognised with the award of this contract," said Chris Merridew, managing director. "We have worked closely with Sirius Minerals and Arup to develop a solution that meets their stringent specification."