In the heart of downtown America, a bustling construction site hums with activity as crews work to expand a hospital with a state-of-the-art proton therapy building. The project involves removing a 30-foot-deep foundation, complete with elevator and gantry pits extending to 40 feet, all while navigating the challenges of bedrock and the need for minimal disruption to surrounding buildings.
To achieve this delicate balance, the team turned to not just one, but two Antraquip
AQ-4XL drum cutters (grinders, cutter heads, etc.), a careful decision based on past success, precision and reliability.
Meeting High-Stakes Demands
The project required careful planning, especially given the hospital's sensitivity to vibrations. Inside one adjacent building to the jobsite, robotic surgeries are performed, where even minor vibrations could jeopardize procedures or damage equipment. Past experience with hammering techniques had taught the team hard lessons—nearby MRI facilities had previously required work be restricted to off-hours, and even Sundays, to avoid disruptions. Additionally, the use of hydraulic breakers were extremely slow given the sandstone formation had compressive strength upwards of 15,000psi.
For this open cut project, the crew opted to utilize Antraquip’s AQ-4XL cutters, which they had successfully used on a prior tunnel and logistics building project after getting tired of being shut down. These powerful attachments (215hp) mounted on CAT336 and CAT340 excavators offered a low-impact solution to efficiently tackle the bedrock, ensuring hospital operations continued uninterrupted.
Why the AQ-4XL?
The superintendent highlighted several advantages of using the Antraquip
AQ-4XL drum cutters over traditional methods like hydraulic hammers:
Efficiency: Production rates with the Antraquip drum cutters will exceed the output of comparable sized hammers in most cases, allowing the team to stay on schedule without resorting to off-hour/overtime work.
Minimal Vibration & Noise: Unlike hammers, the AQ-4XL and other AQ cutters minimizes vibrations, a critical factor for maintaining the integrity of hospital operations and sensitive medical equipment. It is also much quieter and less disruptive than an impacting hammer.
Reusable Product: The cutter produces material that can be reused or sold to other contractors, adding value to the excavation process. This is all done without having to bring in specialized rock processing machines, keeping costs down.
Real-World Results
With the two AQ-4XL cutters in action, the crew efficiently removed the old foundation and carved into the bedrock at depths of up to 40 feet. The super noted how the precision of the cutters allowed for straight, clean cuts, minimizing overhangs and loose rock while maintaining a controlled excavation process.
“We can really create a straight up-and-down cut and keep it clean,” he said. “That makes a big difference in both safety and productivity.”
Setting a Standard for Urban Excavation
For the superintendent and his team, the success of this project reaffirmed the AQ-4XL’s value as a go-to tool for rock removal where production, precision, and low-impact excavation are paramount.
“I think they are the way to go,” he concluded. “It’s low impact, makes a better product, and offers better productivity and control compared to a hammer—it’s definitely the way to go.”
With the proton therapy building taking shape, this project is a great example of how Antraquip rock cutting equipment can make all the difference when facing unique challenges of hard rock excavation projects.
