Date of Graduation


Document Type


Degree Type



Statler College of Engineering and Mineral Resources


Mining Engineering

Committee Chair

Yi Luo.


Mine gas explosion is one of the most feared hazards in the coal industry worldwide. More often one gas explosion related accident can cause the death of multiple coal miners. Since the beginning of coal mining, numerous mine workers have lost their lives as a result of gas explosions. Such occurrences have long been a major concern for mining engineers. Examination of two coal mine disasters (Sago mine and UBB mine) that have occurred in the U.S. in recent years reveals that all explosions originated from or around the sealed areas. Therefore, a good understanding of the atmospheric status in a sealed coal mine area is crucial in preventing and reducing accidents associated with mine combustible gases and also for planning and implementing a mine rescue strategy. Due to the lack of comprehensive research carried out so far in this area, this dissertation work seeks to contribute to understanding the behavior of a coal mine sealed volume and improving safety in coal mines. The following improvements have been made in this research:;• Important influential factors to control the mine atmospheric compositions has been investigated and analyzed. They are: (1) effect of the barometric pressure change; (2) effect of coal mine seals; and (3) categories of gases making up the sealed atmosphere and their changing characteristics.;• Based on the principle of mass conservation and the ideal gas law, a stepwise dynamic mathematical model that uses the control volume approach to simulate the sealed mine atmospheric gas species changes over time has been developed. All the above mentioned influential factors have been incorporated into the mathematical model.;• A modified Coward explosibility diagram method is proposed to analyze the explosive mine atmosphere. The improvements include: (1) expanding the original Coward diagram; (2) corrections of flammable limits; (3) redefining the nose limit for each combustible gas; (4) developing an equation to predict the excess amount of inert gas for each combustible gas; and (5) introducing the concept of explosibility Safety Factor (SF) which improves the Coward diagram's further applications.;In order to facilitate these researches findings and improvements, a new software program, CIMMAS (Comprehensive and Integrated Model for Mine Atmospheric Status), has been developed. The program is coded using an object-oriented programming (OOP) language, Visual Basic 6.0. It offers friendly graphical user interfaces with schematic views and allows users to reduce input works and understand the program outputs.