Conveyor System - Channel Tunnel Rail Link
VVB Engineering Services 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:
- Prepare a design specification
- Appoint a designer and manufacturer
- Approve the design
- Oversea 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%.
