Potomac River Tunnel
Washington DC, Potomac River Tunnel project achieves productivity gains with Conquip’s BulkX.
ContractorCBNA (Civil Building North America) JV for DC Water
LocationWashington DC, USA
The Project
The Potomac River Tunnel (PRT) marks the next major phase of the DC Clean Rivers Project. This phase includes constructing a large-diameter deep sewer tunnel, along with diversion facilities, drop shafts, and support structures. These components capture flows from existing combined sewer overflows (CSOs) along the Potomac River and convey them to the Blue Plains Advanced Wastewater Treatment Plant for treatment.
The Challenge
The project team excavated eight shafts to create outfall locations on the river. They removed large amounts of muck and spoil at depths of around 20 metres, then continued to excavate through a hard rock layer below.
During each phase, the team needed to efficiently remove material from the bottom of each shaft, lift it vertically using a crane, transfer it to muck-away zones, and load it onto trucks for removal from the site.
The Solution
Conquip manufactured two 12,000-litre capacity BulkX units and provided a customised gantry that allowed muck to discharge directly into waiting trucks.
This solution gave the project a high-capacity, reliable, and robust method for muck removal. The BulkX units increased the excavation and material removal rate while improving safety and eliminating people-plant interface risks.
Results
The excavator operator filled each BulkX with muck, and the team then lifted it from the bottom of the 20-metre-deep shaft to the surface, repeating the cycle continuously. Each cycle moved about 14m³ of material every 6–7 minutes, enabling the team to load approximately 9 trucks per hour.
Conquip’s BulkX significantly accelerated the excavation process and reduced project dig times.
Project feedback
“The biggest benefit of working with Conquip’s BulkX system is they’ve been hands-on in helping us develop and really bring the efficiency to the system – and we’ve also bought things to the table and shown them that has helped with the efficiency too. So it’s been a good collaboration.”
“We actually have the advantage of live loading the truck instead of using the muck bins. So instead of having to drop the material into the muck bin and then reload it with another piece of equipment, we actually cut down on how much staffing we need for that and we get to live load the truck and send them straight away from the job site. The spoil doesn’t have to be double handled – it just saves us so much time and hassle.
“I would always recommend the BulkX system for mucking away. Conquip are very straightforward, trying to engineer for efficiency and make it better once it’s there.”
Tyler Wilt | Site Manager, CBNA
MORE PROJECTS
- Incremental struts: Enabled precise width adjustment to suit specific trench profiles, reducing the need for multiple box sizes.
- Rocker system: Provided a simplified and faster setup, especially when working on uneven or complex ground conditions.
- Modular flexibility: Allowed Garde to reconfigure the setup quickly as site conditions changed, minimising downtime.
- Robust design: Engineered to withstand high ground pressures typical of deep utility installations, improving safety and performance.
Smart Purchasing: Hire-to-buy Civil Equipment
Instead of buying the system outright, Garde opted for Conquip Engineering’s hire-to-buy structure—a strategy that delivered immediate site readiness without locking up capital. Over the course of the project, monthly payments covered the use of the equipment and contributed toward full ownership at the end of the term.
This approach allowed Garde to:
- Avoid delays waiting for gear availability.
- Trial the system in live conditions.
- Allocate costs efficiently within the project budget.
Entrenched Success
The CQE hire-to-buy model gave Garde exactly what the Rosehill project needed: dependable, flexible trench support across a complex, evolving worksite, while also strengthening the business for future jobs.
By shifting from hire to ownership, Garde eliminated ongoing rental costs and avoided delays tied to equipment delivery or changeovers. With trench boxes always on site, work progressed without interruption.
Owning the system also added a valuable, reusable asset to Garde’s fleet, ready to deploy on future infrastructure projects without the hassle of new hire agreements.
If your project could benefit from a hire-to-buy approach, contact us at (02) 8844 4590 or email sales@conquipgroup.com.au to explore your options."
["post_title"]=>
string(62) "How Garde Services Turned a Hiring Burden into a Strategic Buy"
["post_excerpt"]=>
string(0) ""
["post_status"]=>
string(7) "publish"
["comment_status"]=>
string(6) "closed"
["ping_status"]=>
string(6) "closed"
["post_password"]=>
string(0) ""
["post_name"]=>
string(58) "garde-services-turned-a-hiring-burden-into-a-strategic-buy"
["to_ping"]=>
string(0) ""
["pinged"]=>
string(0) ""
["post_modified"]=>
string(19) "2025-06-06 09:44:10"
["post_modified_gmt"]=>
string(19) "2025-06-06 08:44:10"
["post_content_filtered"]=>
string(0) ""
["post_parent"]=>
int(0)
["guid"]=>
string(80) "https://cqegroup.com/au/case-studies/city-tattersalls-redevelopment-sydney-copy/"
["menu_order"]=>
int(1)
["post_type"]=>
string(12) "case_studies"
["post_mime_type"]=>
string(0) ""
["comment_count"]=>
string(1) "0"
["filter"]=>
string(3) "raw"
}
How Garde Services Turned a Hiring Burden into a Strategic Buy
Garde Services
How Garde Services Turned a Hiring Burden into a Strategic Buy
Sydney
See how Garde Services used CQE Group’s hire-to-buy trench box system to reduce long-term shoring costs on Sydney Metro West and secure reusable assets.
City Tattersalls Redevelopment: Efficiency in Heritage Restoration with BulkX
DECC
City Tattersalls Redevelopment: Efficiency in Heritage Restoration with BulkX
Sydney
BulkX Direct-to-Truck system streamlined the process while ensuring safety, efficiency, and minimal disruptions.