Work Finishes on Olympic Power Tunnel in LondonConstruction of two tunnels to take power into the Olympic Park has been completed. Four Lovat TBMs dug the two 6 km-long bores, and despite a delay to the breakthrough of the fourth and final TBM, the GBP230 million project has been completed on time and to budget. Delays to the final TBM breakthrough were caused by difficulties in dewatering a 10 m-diameter, 26 m-deep shaft which will be used to connect power cables into an electricity substation in Hackney. Contractor Murphy built a secant piled wall around the shaft to prevent water flooding the tunnel. Visit www.lovat.comThe overall project was kept on track by mechanical and electrical contractors working in completed sections of the tunnel before the final breakthrough. 350 workers have been working around the clock to complete the task in 424 days.Two Continental Conveyor HACs (high angle conveyors) were use on this project. One was using a 1,200 mm belt width and handling 400 t/h with a lift height of 36 metres. The other used a 1,000 mm belt width and handled 300 t/h again with a 36 m lift. There was no internal tunnel belt on this project as muck cars were used. Visit www.continental-conveyor.co.ukTwo 4.15 m-diameter TBMs moving in opposite directions underneath Stratford, east London bored the tunnel to take National Grid power lines underground. Two other 2.82 m-diameter TBMs did the same on a second tunnel for EDF Energy power lines. This will allow 52 electricity pylons to be demolished so that construction work on the Olympic park can start next summer. Click here, here, here and uk/28. 26/07.