Landmark conveyor system removes muck in Ohio 09 Nov 2017

On October 18, 2017, a 9.26m (30.4ft) diameter Robbins Crossover TBM started work on the Akron Ohio Canal Interceptor Tunnel (OCIT) in Ohio, USA. Running behind the Crossover TBM is the 100th Robbins continuous conveyor system supplied for muck removal. The conveyor is side mounted and follows a standard design but marks a significant landmark.

“With this system we have provided more conveyors than any other TBM conveyor supplier,” said Dean Workman, Robbins Director of Conveyors, Cutters, & SBUs.

Celebrating a landmark – the first conveyor was used in 1963

The Robbins Crossover (XRE) TBM and its continuous conveyor system began excavation on October 18, 2017

The Robbins conveyor system consists of the belt plus a main drive, splice stand, storage unit, and advancing tailpiece, operating through several curves requiring patented self-adjusting curve idlers that correct themselves based on varying belt tension and belt load. The system discharges onto a customer-supplied overland conveyor, which delivers the muck to a large storage yard near the portal site. The belt was designed to handle variable geology, from soft soils to partial face rock and finally full-face shale rock.

The 100^th conveyor system has been refurbished and customized for the job: “We design our conveyor systems to last for five to ten years, but many last for decades longer. We have systems utilizing components that have been in operation for 30 years,” said Workman.

The conveyor in Akron is part of a long history for Robbins conveyors—the first of which was the first ever continuous conveyor system used behind a TBM. That prototype, developed by founder James Robbins in 1963, was successfully used behind the 11.2m (36.7ft) diameter Main Beam TBM at the Mangla Dam project in what was then known as West Pakistan. While conveyors would not be adopted as a standard method of muck removal for many years afterward, the project laid the groundwork for future success.

Today the conveyor systems are capable of spanning dozens of kilometers and hauling 1,800 metric tonne an hour or more. “This is my 20^th year with Robbins and I remember when we started our conveyor list. It is amazing to look at all of the jobs and things we’ve done. It’s amazing to see what these systems can do,” said Workman.