A mine door system which includes a mine door having a door leaf, and a door-moving mechanism that articulates between a first configuration in which the mechanism applies a relatively smaller door-moving force to the door leaf and moves it at a first speed and a second configuration in which the mechanism applies a larger door-moving force to the door leaf and moves it at a second speed less than the first speed.

A mine door system which includes a mine door having a door leaf, and a door-moving mechanism that articulates between a first configuration in which the mechanism applies a relatively smaller door-moving force to the door leaf and moves it at a first speed and a second configuration in which the mechanism applies a larger door-moving force to the door leaf and moves it at a second speed less than the first speed.

A mine door system which includes a mine door having a door leaf, and a door-moving mechanism that articulates between a first configuration in which the mechanism applies a relatively smaller door-moving force to the door leaf and moves it at a first speed and a second configuration in which the mechanism applies a larger door-moving force to the door leaf and moves it at a second speed less than the first speed.

An underground ventilation system having a fan, a plurality of ducts for the delivery of air to an underground work space, flow control dampers at duct branches, a fan sensor module to detect velocity, pressure, temperature and/or humidity, a work space sensor in each work space, a connection panel in communication with the fan sensors and with each automated flow control damper and configured to exchange status and control information with the fan sensor, the flow control dampers, and work space sensors, a cabling system attached to the ducts and connected to the connection panel and to automated flow control dampers, and a display and control system in electronic communication with the fan, the fan sensor, the automated flow control dampers, and the work space sensors, via the connection panel.

An underground ventilation system having a fan, a plurality of ducts for the delivery of air to an underground work space, flow control dampers at duct branches, a fan sensor module to detect velocity, pressure, temperature and/or humidity, a work space sensor in each work space, a connection panel in communication with the fan sensors and with each automated flow control damper and configured to exchange status and control information with the fan sensor, the flow control dampers, and work space sensors, a cabling system attached to the ducts and connected to the connection panel and to automated flow control dampers, and a display and control system in electronic communication with the fan, the fan sensor, the automated flow control dampers, and the work space sensors, via the connection panel.