Earth Boring Co. Completes Critical HDD to Deliver Clean Water
Mississauga, Ontario-based Earth Boring Co. Ltd. takes great pride in being part of a project team building a new, complete water distribution system to deliver clean drinking water to the Chippewas of Nawash Unceded First Nation.
The Chippewas of Nawash Unceded First Nation is in Neyaashiinigmiing, Ontario – approximately 55 km north of Owen Sound and 25 km northeast of Wiarton – on Georgian Bay. This critical water system upgrade includes the construction of a water treatment plant, below-grade reservoir, and an intake to draw raw water from Georgian Bay. Earth Boring was responsible for the horizontal directional drilled (HDD) installation of the raw water intake and pre-treatment lines.
In addition to the new treatment plant and intake, to account for future growth in the area, the project also included the repair and replacement of existing water mains and expansion of the distribution system. The goal of the project is to provide residents in the area – who have been on a boil water advisory since 2019 – with a safe and reliable drinking water supply.
“This was a very rewarding project to be a part of. We often take things for granted when we’re drilling sewer and water for municipalities and private developments in the GTA,” says Earth Boring CEO Gene Woodbridge. “It’s rare you’re putting one in so people in an established community have clean drinking water, which they have been without for a while.”
The project consisted of a 500-m long intake (380 m of which was drilled into the lake) and the pullback of a bundled 350-mm HDPE intake and twin 140-mm HDPE treatment lines. An additional 140-mm line was later added to aid in grouting the bore path.
When it comes to drilling projects, this wasn’t the most complex project Earth Boring has completed, though it was one of the most impactful.
“Rewind 30 years ago and they would have just split everything open and cut it in. However, today, trenchless, can be the most cost-effective solution,” says Woodbridge. “You don’t often hear that, but in the last five to 10 years trenchless has really come to a point where that is the case.”
Woodbridge adds that going trenchless also decreases the carbon footprint of projects, which is a major initiative of the federal government, which funded a portion of this critical project.
“While there are instances where people prefer dredging something like this in, that wasn’t an option with this location due to a shoreline fishing agreement,” says Kyle Verwey, M.A.Sc., P.Eng., senior project engineer at Earth Boring Co.. “That’s the reason we had to go so far out into Georgian Bay. There is an agreement in place with the First Nations that the shoreline needed to be preserved so we had to go further out to make sure that was protected.”
Verwey was integral to seeing the project to completion. He cites a novel approach in the contract to gather and assess geotechnical data post project award as being key to completing the project on time and on budget.
“One of the great and interesting aspects of this project – and kudos to Associated Engineering [the Project’s Designer] for setting it up – is that there were provisional items in the tender which allowed for pricing adjustments to the HDD work based on the criteria determined in the geotechnical investigation as part of the contract work,” Verwey says.
This, he says, helped eliminate the age-old trenchless project delays related to differing soil conditions due to poor or incomplete geotechnical data. It also helped expedite the start of work, as the release of the project didn’t need to wait for this additional investigation.
“Associated Engineering really did their due diligence to get this set up as part of the contract, so we could get in there, gather the proper data, agree on the soil conditions and cost, gather the proper tooling and get the job done efficiently,” Verwey says.
Drilling started late August 2022 and wrapped up early November 2022 with no weather-related delays on the drilling side. However, some choppy fall water conditions added some complexity to the offshore works.
The most time-consuming aspect of the HDD work had to do with keeping Georgian Bay’s pristine — glasslike — crystal clear clarity. This meant Earth Boring had to minimize any risk drill fluid being released into Georgian Bay, no small feat.
Verwey came up with a plan whereby they piloted down the embankment and out into the bay using its ParaTrack HDD guidance tool from Vector Magnetics. The crew tracked the bore to about 40 m short of punching out into the lake bottom and then the pilot was pulled back. Then they push reamed the hole open and completed several swabbing passes to make sure the bore was clean before flushing as much of the bentonite out as possible then push reaming the final 40 m into Georgian Bay.
Earth Boring Co. relied on its 1.1 million lb. American Augers HDD rig and some custom rod attachments to ensure they had the power to forward ream in the hard rock formation.
“The whole time all of our fluid flow was coming back to our sending shaft rather than blasting out into the middle of Georgian Bay,” Verwey says. “The exposure, and the risk of the slurry getting into Georgian Bay was minimized drastically by our approach.”
As an added barrier, a large turbidity curtain was deployed around the exit point.
“We’ve done this before but in significantly less sensitive situations,” Verwey says. “What made this particular section manageable is that we were dealing with very hard and stable rock, and we knew the hole was going to stay open without fluid holding it up. Due to the number of swabs, it ended up being a pretty big hole. We had three 140-mm. pipes and a 350-mm. pipe all bundled together so there was lots of space to get through. The pre-reaming had to clear out all the bedrock fragments and pull everything back to the sending pit which was 30 m above the belly of the bore. We also didn’t want any excess deflection on the rods considering some tight bend radiuses and we were mainly pushing on them to ream.”
From where the American Augers rig was setup, there was an approximately 12 m elevation difference to the shoreline. The crew drilled down to the level of the low lift pump station elevation, which was 9 m below the lake level right at the shoreline, and then curved it out to come up under the lake about another 380 m away. The total change of elevation from the rig was 40 m, before coming up to hit the lake bottom +/- 10 m below the water surface.
“It was a unique setup, as we were sitting in the rig, you were looking out over the bay and you could see this drastic drop off,” Verwey says. “Our rods had less than 2 m of cover until they got down the hill and then they really plunged down into the hard rock once we got to the shore.”
While Earth Boring’s portion of the overall project was relatively small — in terms of completion time and time on site in Neyaashiinigmiing — it was by no means insignificant.
BGL Constructors Corp., the lead contractor on the water treatment plant portion of project is wrapping things up, as is Bridge Excavating Ltd. the contractor charged with building the distribution portion of the system. The goal is for the plant to produce clean water by September and the distribution system operational by October.
“It’s a rewarding project to be on and the workers in the field really took it to heart,” says Woodbridge. “To be on a boil advisory for six years is way too long to happen in this century.”
Mike Kezdi is managing editor of Trenchless Technology Canada.
