Location: Montreal, Canada
Equipment: AQ-6 on a CAT365
Application: Tunneling
The Problem
A major Canadian contractor was tasked with building a new ventilation tunnel beneath the busy streets of downtown Montreal. The project required sinking a deep shaft and driving a 107‑meter tunnel, ten meters wide and seven meters high, through rock with a uniaxial compressive strength (UCS) of 100 to 170 MPa, conditions far beyond what most drum cutters are designed to handle.
The location created even more complexity. With tightly packed infrastructure overhead and surrounding the alignment, there was zero tolerance for vibration damage. Blasting was ruled out due to the risk to nearby structures, environmental concerns, and strict regulatory requirements. The contractor needed a way to cut extremely hard rock while keeping noise and vibration to a minimum.
The Solution
The answer was Antraquip’s AQ‑6 transverse drum cutter, known for its combination of power and precision. Mounted on a CAT365 excavator and powered by a dedicated hydraulic power unit, the AQ‑6 delivered more than 400 kW of cutting power. Its reinforced drums, robust transmission, and strategically designed cutter bit configuration made it possible to grind through high‑UCS rock while keeping vibration well below thresholds that could threaten surrounding streets, utilities, and buildings.
The excavation began with the shaft before moving into the tunnel drive. The team maintained a disciplined operating cycle: positioning the cutter for optimal engagement, applying consistent feed pressure to balance penetration and tool life, and conducting regular inspections to keep the drums and picks in peak condition. Dust suppression and ventilation were carefully managed to ensure safe working conditions underground.
The Outcome
Even in the extreme rock conditions, the AQ‑6 achieved an average production rate of 12 cubic meters per hour, with higher outputs when conditions allowed. The finished tunnel profile was smooth and accurate, with minimal overbreak, which reduced the need for additional support and cleanup.
This project proved that with the right equipment, setup, and operational approach, drum cutters can deliver in environments once thought possible only for heavy roadheaders or drill and blast. The success also highlighted the importance of close collaboration between the contractor and equipment supplier, ensuring the machine was configured precisely for the geology and project constraints.
The Montreal ventilation tunnel stands as a powerful example of how advanced rock cutting technology can push the limits of what is possible in underground construction, delivering safe, efficient, and precise results in some of the most challenging ground conditions.
Are you facing tough rock conditions and need a cutting solution? Contact our experts to find the best rock cutting solution for your project.
