Say goodbye to costly downtime with the NMT high pressure, bi-folding ventilation door system. Customized to fit any underground tunnel configuration, the NMT doors can operate automatically via sensors and a PLC or can be set up with a simple pull cord on either side of the doors. Available with either hydraulic or pneumatic actuators the NMT bi-fold doors allow smooth traffic flow throughout the mine.

  • PLC control or manual pull cord
  • Available with either hydraulic or pneumatic operation
  • Optional man-doors available
  • High pressure – built to client specifications
  • Heavy duty bolted frame for ease of installation
  • Heavy duty strap hinges ensure door alignment
  • Custom designed to fit drift size and required opening

Fast Acting, High Pressure Air Control

Ventilation Doors
Ventilation doors tunnel solutions
Ventilation doors tunnel solutions


Advance rates of development headings in underground mines have declined steadily in the past 30 years. This decline was driven by two factors: the increased size of access drifts (tunnels) to accommodate larger production equipment; and the need for more support to ensure safety and stability. Both make the ground control component of the development cycle longer.  Current drift development practice generally involves four sequential activities. This four-stage sequence of activities requires the re-entry of four pieces of equipment, and critical time is often lost between the re-entries. No face activity can be carried out until the ground control is complete and in some cases, support must be installed on the face of each heading after each blast.

The Rapid Advance Shield has been designed and manufactured by NMT alongside the Centre for Excellence in Mining Innovation (CEMI) to safely speed up tunnel development by allowing ground support, drilling, and loading to happen concurrently instead of sequentially.   It accelerates the time while providing protection for production drilling, drift rehab, brow protection/draw point mucking, emergency situations and more. The need to screen and rock-bolt the face is eliminated reducing tramp metal and downstream delays.

Field testing is ongoing with the Rapid Advance Shield, with anticipated completion date set for early 2018. Data simulations have shown advancement rate will be doubled with this implemented technology. 

Get to ore faster and safer!

Conventional Sequential Lateral Development Activities

Conventional Sequence

Potential Concurrent Lateral Development Activities

Time Saving Sequence