The Best Tool Isn’t Always the Newest Tool

Image of Hydro Generators/Pumps Deep Inside Northfield Mountain.

By Tim Rzeszutek

Recently Elm was awarded a project to replace the original 1970 conduit and failed secondary 4160V station service feeder for FirstLight’s flagship facility located at Northfield Mountain in Northfield, MA. Northfield Mountain is a giant water battery capable of powering more than 1 million homes for up to 7.5 hours each and every day. More info on Northfield Mountain can be found in this link (New England’s Largest Battery Is Hidden Inside A Mass. Mountain | WBUR News).

Now, I know what your thinking: this is supposed to be an article about new tools and flashy technology. Well, your about 90 percent right. Bob has asked me to write a column for the monthly newsletter about tools, technology and some of the creative out-of-the-box thinking used to solve the everyday challenges we are encountered with. In this case, the best tool isn’t some new, shiny Milwaukee battery-operated tool with a bluetooth app. Instead, it happens to be a tool first patented in 1920 known as an “Apparatus for Concrete Work,” also known today as a concrete truck.

More to come on the concrete truck and how it helped us keep our tight schedule, but let’s first understand our scope of work and the challenges we faced.            

Elm was challenged with first disconnecting, removing, and then installing new conduits, cables and junction boxes for the existing 4160V feeder and associated control wiring circuits from the switchgear and control room located deep inside Northfield Mountain to junction boxes located at the opening of the mountain. Overall, these conduit runs where just over 2000’ long and were buried along the narrow space alongside the road used to enter and exit the generating station. When I say narrow… that might be an understatement. I’d be lying if I said I didn’t have some real concerns with trying to dig along this road and getting the footages we needed to daily to meet the schedule. Ben Haynes and Derek Helie, who were developing the quote and proposal, never wavered on us being able to get it done. They knew it was a challenge but also had the confidence in the team that would be getting the actual hard work done.

Image of the opening of tunnel into Northfield Mountain.

After de-energizing, disconnecting and grounding out the cables, Elm crews started removing cables from conduit and hauling out of the mountain to the dumpster. Next steps were to remove existing conduit that where buried alongside tunnel road. Tunnel access for plant operations needed to remain open so our crew were in charge of shutting down a section of one lane and controlling traffic flow as we moved alongside the road. Elm crews would pull existing conduit up through the existing soil with the use of a skid steer equipped with material handling forks, cut the rigid conduit into manageable sections and then throw it into our stakebody for removal out of the mountain. Behind them was a crew from Bill’s Concrete & Construction (subcontractor hired by One D to complete excavation & backfilling work) excavating the soil that was loosened up by the removal of the conduit ahead of them. This operation was completed with the use of a mini excavator, which was challenged with digging out materials without damaging the existing curb and road. In more locations than desired, the Bill’s Concrete & Construction crews resorted to hand digging. All the machine and hand excavated materials were loaded into a dump truck and removed from the tunnel. Behind the excavation work was a team of electricians installing conduit and handholes to the trench. Finally, these trenches would need to be backfilled with new stone materials.

Image of the access road in the mountain. New Electrical conduits were installed along the narrow almost impossible to see gap between curb and solid rock wall on the left hand side opposite of the exposed utility racks on the right hand side.

As our crews began completing this work, it was quickly realized that the slowest link in the chain was the backfilling of the trench. A skid steer equipped with a bucket was driving to the exterior of the mountain loading a bucket of stone and then driving down to the trench section to fill it. The trench was taking pretty much a full bucket of material which meant every 6’ or so of trench required a trip out of the mountain. Bringing in another dump truck with materials and another excavator to backfill with was also not an option as we would have had to shut down even more of the road, would to have had to add another operator and machine outside to load trucks, or we would have had to manage timely materials deliveries from suppliers that just want to dump and go and are not interested in slowly being offloaded for hours.

This is where the Bill’s Concrete and Construction crews came up with the innovative idea of using concrete trucks to deliver stone. You heard me right, concrete trucks without all the other components of general concrete mixture, but rather just stone. It was a genius idea of which none of us had ever heard of. We’re not even sure if the Bill’s Concrete guys had ever thought of or had done this before. Either way it was a perfect solution for our problem. Trucks could show up pull right in the tunnel unload directly from their chute into the trench and be out of the tunnel in minutes. It was safer, faster, cheaper and didn’t require us shutting down more road access. It’s this type of innovative thinking that we love to see from Elm employees and our subcontractors.            

Elm/OneD crews ended up finishing the project safely, on time and under budget. The stone backfilling wasn’t the only challenge on this project, but that’s a story for another day.

I would like to thank everyone involved with this project, as I know they went above and beyond like all of us do almost everyday to keep our schedules and customer happy. I can confidently say I think we will be working with FirstLight in the future after a strong showing on this first project with them.