Pressure characteristics and dynamic response of coal mine refuge chamber with underground gas explosion

A gas and coal dust explosion is potential hazard in majority coal mines. A coal mine mobile refuge chamber is a new class of device for miners those who are unable to escape after an accident which can provide basic survival conditions. In this paper, in order to study the propagation law of an underground methane/air mixture explosive wave, and check the failure mode of a coal mine mobile refuge chamber, a full-sized underground tunnel model and a refuge chamber model have been established in ANSYS/LS-DYNA (LSTC, R7.0.0, Livermore, CA, USA, 2014). The simulation results show that the reflected wave pressure on the front surface of the refuge chamber was about twice as high than the incident wave. The pressure on various locations of the chamber was also analyzed. When the peak pressure of the explosive shockwave reached 0.64 MPa, the maximum displacement and stress occur at the center of the front door and the joint of stiffeners and the front plate, respectively. Most parts of the coal mine mobile refuge chamber were in a plastic failure state and the refuge chamber could be defined as damaged. The front door, the front plate, the connecting flange, and the stiffeners on each side were the primary key components. In the end, suggestions were proposed for the refuge chamber.

Experimental Study of the Gas Leakage and Optimized Supply of Oxygen in Coal Mine Refuge Chamber

Removable steel refuge chamber is a very important device for lifesaving in coal mine disasters, such as fire, gas explosion, roof fall, and so on. So the chamber body should have good stiffness, strength, and tightness under disaster conditions. The stiffener structure in refuge chamber body has been investigated with FEM, and a kind of design was suggested.

Experiment research aiming at the anti-explosion capability of the refuge chamber is a complex work with high costs. By using finite element analysis, however, could avoid this issue and implement the simulation and analysis more effectively. Based on transient dynamics approach, numerical simulation calculation and analysis of the dynamic response of the refuge chamber under the impact caused by gas explosion are presented in this paper. The results indicate that, when the refuge cabin under specified explosion impact wave stress, the maximum stress of the cabin is 370.8MPa,which is under the ultimate strength, and the maximum impact wave deformation of the cabin is 9.43mm, which is under the maximum permissive deformation (20mm), therefore the rigidity and the strength of the cabin both meet the demands. The refuge chamber presented in this paper, which remain the integrity of the cabin and the safety of the structure under specified explosion impact, has good anti-explosion ability, and could implemmet the emergency risk avoiding effectively.

Simulation analysis on structure safety of coal mine mobile refuge chamber under explosion load

To investigate the dispersion process of the underground toxic gas carbon monoxide (CO) into the refuge chamber during a mine disaster and enhance the survival rate of trapped miners, a simplified model of an underground refuge chamber and the main roadway was constructed. The impact of temperature and pressurized air volume on CO dispersion into the refuge chamber has been examined through both analog experiments and numerical simulations, and the reliability of the simulation results was verified. The results indicate that CO dispersion into the refuge chamber through the top of the protective isolation door occurs when the temperature in the refuge chamber is lower than that of the toxic gas. When the temperature of the toxic gas is higher, it tends to enter the refuge chamber through the bottom of the protective isolation door. The evolution of CO concentration in the transition chamber can be divided toxic survival chamber can be categorized into a sudden decline stage and a stable stage. And a flexible isolation door designed to control the entry of toxic gases into the refuge chamber was implemented, and its impact on CO dispersion has been compared and analyzed. When the temperature of the main roadway is 50 °C and the temperature of the refuge chamber is 20 °C, the required pressurized air volume to maintain the CO concentration within the safe threshold (24 ppm) is reduced to 69.6% of that needed without the isolation door, thereby significantly reducing the infiltration of harmful gases from the main roadway into the refuge chamber.

The coal mine refuge chamber is the necessary production of emergency system used in the underground coal mine. It can be installed conveniently and moved with the workplace. So it is more widely applied. The composition and basic performance requirements of coal mine refuge chamber were introduced in this paper. The performance of reinforcing ribs was done by finite element analysis software ANSYS Workbench and the performance optimization method of square tube reinforcing ribs thin plate was proposed. It can provide some reference for the design and performance research of refuge chamber bulkhead.

The refuge chamber provides a safe space where people can stay safe when they are trapped by an accident in a coal mine. The refuge chamber includes several systems such as oxygen supply, air purification, cooling, and dehumidifying. The oxygen supply system is the core of the refuge chamber because it is a closed environment. The oxygen supply time is 96 h according to the relevant standards in America and China. If people stay in the refuge chamber for more than 96 h, the oxygen supply may not be enough, and they can be in danger. It is necessary to efficiently use oxygen and extend the oxygen supply time. Based on the experimental platform of the refuge chamber, this paper conducts an in-depth study on the automatic control of the oxygen supply system. The oxygen supply system and the harmful gas removal system can be automatically and efficiently controlled by the programmable logic controller (PLC) according to the personnel number and the oxygen concentration. The experiment has proved that the system is good and reliable.

As one form of the energy resources, coal is becoming more and more important. Due to the particularity in coal mine production, mine accidents some time occur in countries all over the world, which result in large casualties and economic losses. As equipment that can provides the miners with an emergency shelter when the coal mine accidents occur, the underground coal mine refuge chamber is paid more and more attention by coal mine enterprises, and the application of the refuge chamber is increasingly widespread. The general functions, the classification, and the successful applications of the underground coal mine refuge chamber are illustrated first, and the research significance on the underground coal mine refuge chamber is stated. Following, the development status quo at home and abroad for the refuge chamber is introduced. Then, the implementation methods for the key functions of the underground coal mine refuge chamber are demonstrated. Finally, the prospect for the development of the underground coal mine refuge chamber is stated.

The 2006 Sago, Darby, and Aracoma mine disasters in the United States (US) forced the US government to implement the 2006 MINER Act and additional regulations that require all US underground coal mines to install and maintain refuge chambers to manage entrapment emergencies, in particular, fires and explosions. However, there is a debate on whether barricading in refuge chambers is a good strategy to survive such emergencies. Australian coal mines are not required to use refuge chambers and, instead, have adopted a strategy that focuses on instructing and training miners to self-escape to the surface. This paper analyzes merits and problems of using refuge chambers and self-escape to the surface to manage emergencies in fires or explosions in an underground coal mine. The authors found that the use of refuge chambers may not be the best strategy during extensive fires or when multiple explosions happen. In these situations, mine rescuers are unlikely able to extract miners who are sheltered in chambers and conversely, self-escape may save more lives than sheltering. Chances for successful self-escape are further improved by regular, externally assessed training such as Level 1 Emergency Exercises required in the Australian State of Queensland. These exercises put pressure on mine operators to ensure and maintain the effectiveness of their emergency management system.

The refuge chamber is an important part of the emergency refuge system in coal mine. This paper mainly introduced the design ideas of underground layout, structure, six systems of disaster prevention system, life support system, life support and emergency system, power supply system, communication system and external disaster information detection system in refuge chamber. This provides a scientific design basis for constructing refuge chamber in the coal mine.

The cylindrical shell with rectangle stiffeners was usually utilized in coal mine refuge chambers. Aiming at the buckling deformation of thin cylindrical shell under uniform axial compression, finite element analysis software ANSYS was employed to set up the optimization model of stiffened cylindrical shell, and the sequential linear programming method was executed to optimize the thickness of shell and the sizes of stiffener. The mechanical property after optimization was compared with the theoretical value of no-stiffener shell with equal volume, and reasonable stiffener distribution was obtained while the optimization results of five different longitudinal and circumferential stiffener patterns were gained. The results showed that the shell’s mechanical capacity of axial compression was basically not improved when the stiffeners were too sparse or overcrowded. Nevertheless, in the condition of reasonable stiffeners distribution, it could be improved by approximately 50%. The stiffener pattern and optimal results obtained in this paper are useful for refuge chamber’s shell design.

Developing a new product, such as coal mine refuge chamber, is a risky and uncertain process. In order to reduce the risks and uncertainties, the paper proposed a risk-based design methodology. Based on the theory of formal safety assessment (FSA), the proposed methodology consisted of four distinct steps: parametric design of product, risky factors identification, risk assessment, risk control and decision making. Subsequently, it was investigated that the main risky factors of chamber design were general performance parameters, complexity of operating, flexibility of the product and investment cost. While the four main factors and their fourteen attributes were researched thoroughly, a risk analysis model for chamber design was introduced. Then a case was studied to demonstrate the application of the model, and the results indicated that it was an effective way to reduce the risks and uncertainties of new product, and there were some crucial attributes which should be paid more attention to in technology design of refuge chamber, i.e. the chamber's capability of withstanding overpressure, temperature control, flexibility and investment cost.

Refrigerating characteristics of ice storage capsule for temperature control of coal mine refuge chamber

Probing Into Design Of Refuge Chamber System In Coal Mine