A mine ventilation system provides a fresh air flow to the underground workings in a coal mine. Such sufficient air volume can
dilute and remove noxious gases (typically NOx, SO2, CH4, CO2 and CO) and maintain a suitable working environment for coal
miners. On the other hand, a poor ventilation system often leads to serious consequences such as mine gas explosions, production
loss or higher operational costs. Hence, the functions of mine ventilation system are very important for an underground mining
system. This paper presents a reliability assessment approach for evaluating the mine ventilation system based on a random
simulation method, Monte-Carlo Simulation (MCS). In detail, the first step of this method is to finish probabilistic descriptions of
the mine ventilation network. Then, the criteria of successful conditions are defined. Finally, the Monte-Carlo Simulation (MCS)
method is used for performing the reliability assessment. By using this assessment approach, the random characteristics in the
system can be well considered. Hence, the results are more accurate and reliable. In addition, the risk evaluation for the mine
main fan is also approached by the Monte-Carlo Simulation (MCS) method. Two important problems, the yearly percentage of
loss time due to fan repairing and yearly breakdown times, are answered. Through the paper, a case study has been shown and
investigated to demonstrate the assessment procedure for a mine ventilation system with using the MCS method.