The Challenges of Underground Power Outages

The Challenges of Underground Power Outages and its Impacts on Ventilation and Egress

American Mine Door (AMD) has developed an exciting new underground mine door battery backup system. This backup system is currently undergoing final testing on our test door within our facility. Electrical power outages happen, and when they do, they can create a disruption to a mine’s ventilation control plan. Power outages can also create concerns with personnel and equipment egress. During these outages, mines want more control to maintain operation of their ventilation doors. Customers have also inquired about a door system that could operate in remote areas where there are no electrical utilities or during a power outage within the mine. The possibilities could be endless

The Battery Back Up Test in the Video

You will see in this test video, the AMD patented opposing wing mine door using two wings tied together with a connecting bar at the top of the door. This patented opposing wing design uses the existing air pressure in the mine to create a “balanced door system”. Consequently, the air pressure pushing against one door wing pulls the opposite door wing towards you. This unique design requires less force to open and close due to air pressure assisting the process. For the battery backup design, we have chosen a self-contained electro hydraulic actuator that offers the same force output as a traditional hydraulic power unit. It is an ideal actuator for the battery backup system due the minimal electrical consumption to operate the unit.

The new battery backup system uses two 12 VOLT GEL CELL 100 AH batteries that are wired in series to offer a 24 VOLT system. A smart charger is used to maintain the charge of the batteries as well as identify any problems with the batteries or the charging system. The incoming mine power comes into the charging system, which maintains the batteries. The batteries maintain power to the PLC control system and all the peripheral components. The components in our standard system include: traffic lighting with audible alarm, thru door scanners, roof mounted sensors and door actuation switches. The final battery backup package would include the smart charger, batteries, transformer, inverter and indicator lights all housed in a NEMA 4X enclosure. (SAMPLE Pictured above). Indicator lights are used to identify critical low battery life and when the system is operating on battery power vs. mine power.


Impressive Test Results

TEST 1 – Test door cycled open and close at the end of each hour for 16 consecutive hours on 100% battery power. We achieved a total of 96 cycles and measured a voltage drop of 2 volts.
TEST 2 – Test door cycled continuously open and closed and all the safety peripherals on 100% battery power, testing how many cycles can be achieved. We achieved a total of 1700 cycles at a measured drop of 5 volts.
American Mine Door