Continous Conveyors

Conveyors at the Lower Northwest Interceptor Project

While continuous conveyors have become the muck removal system of choice in long, hard rock TBM tunnels, they have gained acceptance in soft ground tunnels only recently. Several successful projects in Sacramento, California/USA have proven them to be a favorable alternative to muck cars, producing record rates with high system availability.

The absence of muck cars allows for continual operation behind TBMs, factoring into recent weekly EPB advances as high as 210 m.

“The Robbins-supplied tunnel conveyor system performed remarkably well throughout the drive. The availability of the TBM and associated sub-components was in turn very high for a tunnel heading operating 24 hours a day, 5 days per week,” said Jeremy Theys, Project Manager for the Traylor/Shea JV (contractor for Sacramento’s Upper Northwest Interceptor (UNWI) sewer project).

The design of such systems must, however, take into account the differences in material between...

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