## 4 Simulation and Integration Results
### The Comprehensive Comparison of Traditional CFD Method and LBM  
According to the kinetic theory [40], both traditional CFD method and LBM can satisfy the macroscopic Navier-Stokes equation in their continuous forms. However, Navier-Stokes equations are the target for LBM while the starting point for the traditional CFD methods, and these two methods also differ, not only in the spatial discretization forms, but also in the temporal discretization forms. Although a number of studies have been conducted to comprehensively compare their difference in essence, there is still a lack of comparison based on the actual simulation example. In this case study, comprehensive comparison and analysis between the proposed turbulent LBM based velocity-concentration coupling model and traditional CFD method are conducted from the following three aspects: accuracy, simulation efficiency, simplicity, and advantages of the integration with LrGIS platform.  
Figure 10: Point query analysis and data validation.  
Here, the traditional CFD method was implemented based on Computational Fluid Dynamics platform (Fluent) by employing the Euler-Lagrange model, all terms of the governing equations and constitutive relations were solved with the semi-implicit pressure-linked equation (SIMPLE) algorithm and second-order upwind scheme. The turbulence model and boundary conditions were solved using finite volume solver. The dynamic boundary parameters are the same with the LBM. Here, a line at 3 m high in the middle of the outtake side of laneway was chosen to investigate the airflow velocity and methane concentration at two different time points. As can be seen in Figures 11 and 12, it shows that both methods agree well with each other in the overall tendency of airflow velocity and methane concentration.  
The traditional CFD simulation requires about 20 min on computers with four core processors and 8 GB RAM, while the model adopted in this paper uses around 15 min. It is noted that Fluent belongs to the third-party professional fluid dynamics simulation software, its independent geometric modeling and numerical simulation process makes it significantly difficult to directly guide the on-site problems, and the required data have to be preset and saved manually in the early stage of the simulation, which shows the poor practicability when applied in the on-site guidance. However, in this paper, the property of the unnecessary explicit mesh generation and the inherent simplicity of the algorithm make LBM more efficient and easy to integrate with the LrGIS platform. Specifically, the integrated system essentially implemented four objectives: (i) enabling managers to simulate case study directly on the GIS system and visualize the simulated results intuitively; (ii) storing the simulated spatiotemporal field data in the database system, which can be used for post analysis; (iii) demonstrating the simulated field data with various coal mine map objects, and providing miners the spatiotemporal analyze and query operation tools to obtain the useful location-based information; (iv) validating the results based on the coal mine monitoring system of Sijiazhuang coal mine. Therefore, by utilizing the synergies between GISs and spatiotemporal modeling, the integrated system is effective in providing decision  
Figure 11: Airflow velocity at the selected line.  
Figure 12: Methane concentration at the selected line.  
supports for safety production, which is expected to improve the health standards in the underground coal mines.  
The comparison case study demonstrates that the model and integration mode carried out in this study is more efficient in improving the computational efficiency and simplifying the integration mode of numerical simulation model with the GIS platform. It can also be concluded that the integrated system is more practical in on-site application compared with numerical simulation software.