Clamshell excavators excel on London Crossrail

Two Hitachi excavators with clamshell telescopic arms have helped contractors meet deadlines on the massive London Crossrail project in the UK.

The ZX350LC-3 and ZX350LC-5 units, both rented from M O'Brien Plant Hire, were used by Costain Skanska Joint Venture (CSJV) for excavation duties on two shafts to a depth five storeys below ground for the new Crossrail station at Bond Street.

CSJV conducted a test to compare the performance of the clamshell telescopic excavators against the traditional method of skips and a crane. Costain works manager Martyn Redsell said; "The ZX350LC-3 excavator was three times quicker than using an eight-cubic-metre skip. The skips removed 13 cubic metres per hour compared to 39 cubic metres per hour removed by the Hitachi. By mid-May, we were four days ahead of schedule."

Between March and June this year, the ZX350LC-3 - using a 25 m arm and 1.2 cubic metre bucket - worked 24-hour shifts, seven days a week, removing material from the first shaft.

The ZX350LC-5, the first of its kind in Europe, arrived in July 2012 to start work on the site's second shaft before moving onto another Crossrail site to carry out similar duties.

The shafts will be used to allow access for the tunnel boring machines which will arrive later this year.

Michael O'Brien, owner of M O'Brien Plant Hire, based in St Albans, Hertfordshire, said the machines offered major advantages; "The benefits include increased safety and flexibility in terms of where we can work. They give our company greater versatility; we can reach more customers with these machines."

The two units were sold to the rental company by Hitachi's UK dealer, HM Plant.

Crossrail, which is understood to be the largest ongoing civil engineering project in Europe, comprises the construction of a new railway across London connecting 37 stations, including Heathrow Airport in the west and Canary Wharf in the east.

Last year Speedy Hire said Crossrail would generate more rental revenues than the London 2012 Olympics project.