Research Article A Study on Preventing Spontaneous Combustion of Residual Coal in a Coal Mine Goaf Yongjun Wang, 1 Xiaoming Zhang, 2 Yuichi Sugai, 1 and Kyuro Sasaki 1 1 Department of Earth Resources Engineering, Faculty of Engineering, Kyushu University, Fukuoka 819-0395, Japan 2 Institute of Engineering and Environment, Liaoning Technical University, Huludao 125000, China Correspondence should be addressed to Yongjun Wang; yongjunwang2012@gmail.com Received 29 December 2014; Accepted 6 March 2015 Academic Editor: Umberta Tinivella Copyright © 2015 Yongjun Wang et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Te efectiveness of grouting scheme has been simulated to prevent the coal spontaneous combustion at a goaf in Haizi Colliery, China. Te colliery has been operated for long period over 27 years and has a complex ventilation network including airfow leakages which could possibly lead to the spontaneous combustion of coal at goafs. Firstly, the mine ventilation simulator MIVENA was used to analyze the mine ventilation network airfows to control airfows in and out of working faces and goafs. As the second approach, numerical simulations were carried by the simulator FLUENT in order to predict spontaneous combustion of residual coal with leakage fow in the #3205 goaf. It was cleared that the goaf can be divided into three zones based on oxygen concentration in the goaf area. Finally, the numerical simulation results show that the slurry grouting method is able to be an efective and economical method by reducing porosity in the goaf area to prevent spontaneous combustion of residual coal. 1. Introduction It is well known that the key area relating to underground coal mine fre is goaf areas where there exists a potential to induce spontaneous combustion of residual coal in the goaf areas. According to the statistics of Chinese coal production, 90% of total production coal is produced by underground mines, and there are around 600 state-owned key coalmines of which 25.1% are highly gassy mines and 17% are gas out- burst mines, approximately [1]. In Chinese underground coal mines, serious accidents occurred especially in last ten years. Since they produced a large amount of coal meets domestic demand, it resulted in insufcient efort to keep safety operations at working faces and goaf areas. In particular, most of the accidents were directly or indirectly related to coal spontaneous combustion in goaf areas. Qi and Chen (2009) [2] studied the distributing condition of abutment pressure and air fowing state in goaf and then presented the theoretical formula to predict airfow velocity in goaf area and the spontaneous combustion zone where airfow velocity is less than 0.24 m/min. Pan et al. (2013) [3] analyzed a goaf and divided it into the three zones related to coal spontaneous combustion using with distribution of O 2 and CO concentration. Tey classifed the goaf area to radiating and asphyxiation zones by O 2 concentrations larger than 18% and less than 7%, respectively. In this research, a preventing method for spontaneous combustion of residual coal at a goaf in Haizi Colliery has been studied, because it is a typical lignite coal mine in China and has a potential to get spontaneous combustion due to fusain existing in coal beds [4]. As shown in Figure 1, the Haizi Colliery’s mine area is nearly 6.44 km 2 consisting of 1,200 to 5,200 m along the strike and 0 to 1,700 m in tendency. Its coal seams are clef by three normal faults that formed an isolated block area like a triangle coal-bearing zone. Te current level that operates working faces is −320 m from the surface. Average self-ignition point of the produced lignite coal is 275 ∘ C. And the elapsed time afer contacting air to spontaneous combustion in a pail has been estimated as roughly 1 to 1.5 month [5]. Based on the mine’s operation record during 2002 to 2013, spontaneous combustion phenomenon has been frequently observed at working faces. Te characteristics of Haizi coal are listed in Table 1. Hindawi Publishing Corporation Journal of Geological Research Volume 2015, Article ID 712349, 8 pages http://dx.doi.org/10.1155/2015/712349