The third TBM completed excavation of the 4.9km length of tunnel running between shaft number seven and shaft number six near Al Mafraq in Mohammed Bin Zayed City, marking its accomplishment of contract T-02, a 15km central section of the sewer.
The third TBM began tunnelling in July 2011 and progressed steadily at rates of up to 100m per week. The contract, worth AED 891M (USD 243M), was awarded to Impregilo on September 2009.
The total length of the STEP deep sewer tunnel is 41km. The third contract, also awarded to Impreglio, will complete the remainder of the tunnel excavation. A total of eight TBMs will be used to excavate the entire tunnel.
