Collision avoidance and underground communications are subjects of an article in the September issue of the magazine. American Mine Door’s (AMD) latest Door Collision Avoidance System provides warning lights and audible alarms to assist drivers in getting through high pressure doors safely. AMD says its “new light curtain system for collision avoidance can be used with our own unique opposing wing high-pressure doors or retrofitted to assist with any existing mine door installation.

The system consists of four rib mounted sensors, one on each rib, on both sides of the approach to the mine door. Each light curtain is mounted a predetermined distance from the door, far enough to provide an effective warning to the driver if the vehicle strays from centre. Infrared light curtains, each with a coverage area of 0.3 m by 3.35 m, are projected to within a few millimetres of the inside of the door wings. In the event that a vehicle gets too close to one side of a rib, the sensor detecting the off-centre vehicle sets off an audible alarm and flashing red strobe light as a warning.

Between the door and each light curtain a 110 dBA audible alarm and flashing red strobe light are mounted. In the event a vehicle strays off centre of the roadway and breaks one of the infrared curtains, the alarm and strobe for that side let the operator know the vehicle is heading for a collision on that side.

Once the driver makes a correction to centre the vehicle, the audible alarm and strobe shut off to indicate the vehicle is now clear to pass through the doors.

Many times, a vehicle needs to turn directly after going through a door. Since some of these vehicles can be 10 m or more in length, correctly negotiating the curve is crucial. In these cases, equipping the system with a laser can show operators exactly where their front wheels should be positioned to properly make the corner. The visual guidance from the laser ‘path’ helps them negotiate these turns more accurately and consistently.