TERRATEC supplies new TBMs to Mumbai Metro
The Australian Tunnel Boring Machine (TBM) manufacturer, TERRATEC, celebrated the delivery of the first two of a number of new TBMs destined for the Mumbai Metro?s Line 3 project, following successful factory acceptance tests recently.

The first of these was a 6.68 m diameter dual-mode hard rock TBM (T58) that will be one of the two new machines deployed by the Hindustan Construction Company ? Moscow Metrostroy JV to build the twin tunnels on the line?s 4.049 km UGC-02 contract (Chhatrapati Shivaji Maharaj Terminal Station?Mumbai Central Station).

The T58 machine, along with its sister machine (T59), will be deployed later this year from the Chhatrapati Shivaji Terminal TBM launch shaft towards Kalbadevi Station and onward to the Mumbai Central Station TBM receiving shaft for a total of four tunnelling drives (each) over the course of the project.

The second machine delivered (T60) was the first of three new TERRATEC 6.68 m diameter dual-mode hard rock TBMs ordered by the J. Kumar?China Railway No. 3 Engineering Group JV for the excavation of sections on the line?s 4.94 km contract UGC-05 (Dharavi Station?CSIA T1 TBM receiving shaft) and 4.45 km contract UGC-06 (CSIA T1 Station?Marol Naka TBM receiving shaft).

These versatile TERRATEC single shield TBMs are equipped to operate in either Open or Closed mode in the predominantly fresh and slightly to moderately weathered Basalt and Breccia that are anticipated on these contracts. The robust hard rock cutterheads are mounted with heavy duty 17? disc cutters, which are interchangeable with ripper tools, and feature large bucket openings that provide a 10 per cent opening ratio.

Other state-of-the-art features include 2,000 kW Electric Variable Frequency Drives ? that allow the cutterheads to cut efficiently in harder rock zones at maximum speeds of 7 rpm and deliver a torque of 8,000 kNm to cope with more fractured zones of ground along the alignment ? as well as active shield articulation and built-in two component backfilling grout systems, according to the company.

In addition to the new TBMs, TERRATEC also completed the successful factory acceptance testing of two re-manufactured 6.61 m diameter mixed/rock Earth Pressure Balance machines (S63 and S64), which will also be deployed by the J. Kumar?China Railway No. 3 Engineering Group JV in Mumbai. These TBMs were recently used on Delhi Metro?s new Pink Line and have since undergone extensive refurbishment in order to fulfil a section of highly weathered ground on contract UGC-05.