VVB

Construction

Conveyor System – Channel Tunnel Rail Link

VVB Ltd were appointed as the mechanical and electrical engineering contractor for Costain Skanska Bachy JV on The Channel Tunnel Rail Link in 2001. Part of the brief was to:
CTRL C240 Upline tunnel

  • Prepare a design specification
  • Appoint a designer and manufacturer
  • Approve the design
  • Oversee the manufacture
  • Carryout the installation, operation and maintenance of a tunnel conveyor system.

The tunnel conveyor system was a continuous system connected to 2 tunnel boring machines advancing at rates of up to 33 metres advance in a 12 hour period, 7 days a week, 24 hours a day. The tunnel diameter was 7.15m diameter and each tunnel was 4.8km long. The conveyor belt was stored in a cassette underground with a storage capacity of 600m of belting.

Tunnel Conveyor Specification

Belt Width:  800mm
Belt Speed: 3.29m/sec
Belt Tensioning:  Hydraulically operated
12 strand loop
Capacity:800 tons/hour
Material: London Clay, Thanet
Sands: from TBM
Final Length: 4838 metres
Lift: 22.5 metres
Motor: 3 x 160kw
Drive Frequency: inverter

Surface Conveyor System

The surface conveyor system comprised of 5 conveyors totalling approx 400 metres long, all of 1600 tons/hour capacity and 1000mm wide conveyor belt. These conveyors eventually loaded onto a tripper conveyor 100 metres long and some 12m high that discharged onto a special tip.

SCADA System

The entire conveyor system was controlled through PLC’s and a SCADA system remotely in the surface control room. Belt slip, belt tear, belt misalignment and belt break were all monitored for.

Conveyor Performance

The conveyor system was in operation for 12 months. During that time 1 million tons of Thanet sands and London clay were conveyed. The conveyor operated 24 hours per day, 7 days a week for 12 months with an availability of 99%.