Abstract
Coal and gas outburst is the extreme instability caused by stress, gas, and coal. In this review article, dominant factors and inducing factors of outburst were summarized; geologic features of typical outburst cases and the effects of tectonic movement on outbursts were analyzed; the outburst stages with considerations to geologic factors were divided. It was found that inducing factors, including buried depth, tectonic movement, gas composition, coal seam conditions, overlying/underlying rock conditions, and mining mode, control the outburst by influencing the dominant factors (stress, gas, and coal). Among them, tectonic movement is the key of outburst. Influenced by tectonic movement, the primary structure of coals is damaged/pulverized due to the tectonic stress and unique tectonic mode, resulting in the formation of tectonic coals. When external dynamic factors are changed, tectonic coals are crucial to outburst control for its evolution of porous structure as well as the unique mechanical behaviors and gas flowing responses. Besides, the preparation stage of outburst includes the tectonic process and mining process. The former one refers to the restructuring process of the original coal-bearing strata by tectonic movement, while the mining process is the prerequisite of outburst and it refers to the disturbance of human mining activities to the initial coal seams. It is suggested that more work is required on geological factors of outburst, and a few research areas are proposed for future research.
Highlights
Coal and gas outbursts are a kind of sudden dynamic disaster in underground coal mines which have complicated processes [1, 2]
Since the catastrophe process is accompanied by considerable failure effect, outbursts are a great threat to safety exploitation of coal resources, becoming a wide concern around the world [3]
High-intensity exploitation (>30 billion tons) over years leads to gradual exhaustion of shallow coal resources, increasing the coal mining depth year by year [5]
Summary
Coal and gas outbursts (hereinafter referred to as outbursts) are a kind of sudden dynamic disaster in underground coal mines which have complicated processes [1, 2]. Many cases of outbursts have demonstrated that most outburst accidents occur in tectonic zones (e.g., fault, fold, and overthrusting tectonics), which is attributed to the following reasons These tectonic zones change the stress and gas environment in coal seams [2, 14,15,16]. Tectonic coals show extremely weak antidisturbance, and their mechanical behaviors and gas flow become unique upon changes of external factors. Existing studies on geologic causes of outbursts mainly focus on statistical analysis of cases It lacks a systematic study on the changes of the ground stress field and gas field in the original coal-bearing stratum caused by tectonic movements and the physical and chemical changes that coals have undergone under the effect of tectonic movement to form tectonic coals. Discussion on the current research status and future research areas is performed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
