Acoustically sensing the presence of methane and carbon dioxide in underground coal mine

Introduction. Coal mine methane, a greenhouse gas released during underground coal mining, is considered to be a cause of global climate change. However it is also a valuable energy resource. Currently, the global utilization rate of coal mine methane is low, and the amount of methane released into the atmosphere is increasing every year. To limit greenhouse gas emissions, several legislative initiatives have been implemented, including the Kyoto Protocol, the Paris Agreement, and Federal Law No. 296-FZ “On Limiting Greenhouse Gas Emissions”. In the conditions of Donbass, the task of mine methane utilization is relevant due to the dense location of emission sources and the need to improve the safety of mining operations, as well as to ensure the implementation of the principle of integrated field development. In addition, the ongoing hostilities have led to an increase in fuel prices in the region and an increase in road transport due to the limited availability of rail, sea, and air transportation. The aim of the research is to conduct a calculated assessment of the energy efficiency of using mine methane from Donbass coal deposits as motor fuel for commercial vehicles with internal combustion engines.Materials and Methods. As an example, the studies were conducted on BAZ-2215 vehicles on the GAZelle Business chassis, GAZelle Next Citiline, and PAZ 3203, which were commonly used on urban routes in Makeyevka (DPR). These vehicles were equipped with UMZ, ZMZ, and Cummins spark and diesel engines. The full composition of methane-air mixture samples from several mines (Chaykino Mine, Makeyevka, Komsomolets Donbassa Mine, Kirovskoye), taken from degassing systems, was determined in the laboratories of Makeevka Research Institute for Mining Safety and Donetskavtogaz using a Kristallyuks 4000M gas chromatograph. The energy efficiency of engines operating on various types of fuel, including mine methane, as well as the performance characteristics of selected buses (fuel consumption, distance-to-empty, and carbon dioxide emissions) under urban driving cycles according to GOST R 54810–2011, were determined through a series of calculations using well-established methods.Results. An estimation of the energy efficiency of mine methane as a gas engine fuel has been performed. In the range of concentrations of the studied samples of gas-air mixtures, the calculated maximum loss of effective power for ZMZ and UMZ spark engines was up to 15%. For gas-diesel engines, such as Cummins, power could be increased by up to 29%. These findings did not prevent selected buses from operating under driving cycles in accordance with GOST R 54810–2011. Under these conditions, fuel consumption and range per refueling depended significantly on the component composition of mine methane. For the samples studied, it was 1.8–3.5 times worse than for natural gas used for refueling. Emissions of carbon dioxide were reduced by 62–73% compared to gasoline.Discussion. Due to the specific features of degassing processes and the mining and geological conditions of different mines, the alternative fuel discussed in this article has a variable component composition. In this regard, the transfer of PAZ and GAZ bus rolling stock to a byproduct of coal mining — mine methane — is associated with several challenges. These include the need for more powerful fuel systems (three times or more than the power supply systems of internal combustion engines of comparable power, operating on compressed gas) and deterioration in fuel-economic and traction-speed properties of vehicles, as well as reduced range. A quantitative assessment of these changes has been obtained through research. The positive impact of the proposed measures stems from the reduction in negative environmental impact by using mine methane as a fuel for vehicles, which reduces the carbon footprint of road transport and decreases the consumption of liquid hydrocarbon fuel.Conclusion. As a result of the study, it has been found that the methane from the Donbass coal mines can be used as motor fuel for commercial vehicles such as city buses. The study has determined the corresponding energy efficiency parameters (the effective power generated by internal combustion engines, the specific fuel consumption, the range of vehicles under driving cycles, etc.), as well as the degree of their reduction compared to traditional fuels. It has been established that this does not affect the performance of transportation work (in compliance with GOST R 54810–2011) and is beneficial from the perspective of saving non-renewable resources and improving environmental safety in the region.

The presence of methane in coal mines is one of the major problems in underground coal mines. Every year, in underground coal mines, a lot of casualties due to outbursts and explosions of methane gas is occurring. Existence of this gas in the mines not only creates a difficult and dangerous situation for work but also makes it more expensive. The release of this gas to the air causes a further pollution of the atmosphere and increases the greenhouse gases in the air. Thus Coal Bed Methane (CBM) drainage before, during, and after coal mining is necessary. Accordingly, the CBM drainage can reduce the risks involved in these mines. In the past decade, CBM has offered a significant potential to meet the ever-growing energy demand and can decrease the disastrous events. In this research work, the CBM potential in Eastern Kelariz, Western Razmja, Bornaky, Bozorg, Razzi, and Takht coal mines of Eastern Alborz coal mines company is investigated using the rock engineering systems (RES) based on the intrinsic and geological parameters. Nine main parameters are considered for modeling CBM, and the interactions between these parameters are calculated by a proposed system. Based on the RES method, the parameters that are dominant (depth of cover) or subordinate (gas content) and also the parameters that are interactive are introduced. The proposed approach could be a simple but efficient tool in the evaluation of the parameters affecting CBM, and hence be useful in decision-making. The results obtained show that Razzi coal mine has a good potential to perform CBM drainage.

Computational investigation on effects of geo-mining parameters on layering and dispersion of methane in underground coal mines- A case study of Moonidih Colliery

Methane (CH4) is the second most prevalent anthropogenic greenhouse gas (GHG) after carbon dioxide (CO2), with a Global Warming Potential (GWP) 28-34 times more potent than CO2 over a 100-year timeframe. Coal mining, a major source of CH4 emissions, accounts for about 12% of global anthropogenic CH4 emissions (U.S. EPA, 2019). Most emissions come from underground coal mines, predominantly working mines, but emissions from abandoned underground mines are increasing. National monitoring, reporting and verification (MRV) programmes not only help countries better understand the contribution of coal mining to their overall CH4 and GHG emissions, but also identify opportunities for mitigation, ranging from identifying prospective locations for coal mine methane (CMM), abandoned mine methane (AMM) and surface mine methane (SMM) mitigation projects to informing the design of policies for CMM, AMM and SMM.

The benefits of sensor based computer control in the international mining industry are many. Consequently, the industry expends considerable effort researching and developing automated systems. These efforts span the total industry including exploration, extraction, processing, and refining. All of the major segments of the mining industry: underground and surface, industrial minerals, metal, non-metal, and coal have participated in these developments. The result is a large body of information that is impossible to cover completely in a conference paper. To provide interesting information to the conference audience, this paper focuses on efforts to automate mobile production equipment. Most of the efforts apply to international underground metal and coal mines. Mobile mining and construction equipment presently utilize mechanization and remote control. For example, remote controlled equipment, where an operator is stationed some distance from the machine, but within line-of-sight, is found on many continuous mining machines in underground coal mines and LHD'S in underground metal mines. Teleoperated equipment where operators can be stationed further away, beyond-line-of-sight, is currently being tried at mines in the USA, Canada, Australia, and Sweden. Research projects currently focus on intelligent analysis of data from sensors to produce control algorithms which will be termed "mining robotics" to distinguish it from simpler closed ioop control termed "automation." The reason current research focuses on intelligent analysis of sensor data to produce control algorithms is that mining takes place in the geological environment where conditions are highly variable and unpredictable. As a result, mining systems must have substantial cognitive abilities to recognize and deal with these unpredictable variations. Robotics has been described as the intelligent connection between perception and action. It may provide the greatest benefits in productivity and safety since it incorporate artificial-intelligence-based algorithms that show promise for adapting to the dynamic mining environment. Many mines have purchased the latest available technology from equipment manufacturers. These large, expensive, advanced machines have high production capabilities and are very reliable. For these machines to provide the highest cost effectiveness, they should be fully utilized; however this is not always the case. For example, underground coal continuous miners are only utilized 17% of the shift (Suboleski and King, 1990, and King and Suboleski, 1991). These problems occur in surface and underground mines, but underground mining has the most opportunity for improvement. In addition, maintaining an artificial environment 348 / SPIE Vol. 1613 Mobile Robots VI (1991) 0-8 194-0750-X/92/$4.00 in an underground mine that is conducive to optimal work performance is expensive. By its nature, underground mining can be hot or humid, in addition, the equipment produces dust, noise, fumes, and other hazards. Explosive or toxic gases and the constant danger of rock falls add to the increasing list of health and safety concerns that have initiated volumes of federal and state regulations for maintaining safe work places for humans in underground mines. These regulations cause tremendous capital and operating expenditures that prevent many mineral deposits from being mined profitably. For example, in both underground coal and metal mines, miners excavate many more entries or drifts than necessary to produce and remove the ore or coal in order to provide a safe environment for humans. These difficulties will increase as mines deplete nearsurface reserves that have the best working conditions. As a result, some areas are not mined because of the expense of providing an adequate environment for human operators. A good example is narrow ore veins in metal mines that would normally require cut and fill stoping methods to provide adequate ground support. With teleoperated or robotic equipment, less expensive open stoping practices can be used. Another example is automated longwall systems that can be operated more freely in a bi-directional cutting mode because they eliminate respirable dust exposure on the face.

ABSTRACTMethane is associated with the coal has caused disaster in underground coal mines all over the world. However, coal mine gas utilization for fuel is a well-proven technology. Due to the different compositions of mine gas (0.1–95% CH4), this technology is still in a developing stage in India. Based on mine-specific measurement of the rate of emission, all the underground coal mines in India have been categorized into Degree I, Degree II, and Degree III. Coal mine methane is a general description for all methane released prior to, during, and after mining operations. As such, there is considerable variability in flow rate and composition of the various gas emissions during mining operations. From extraction technology and utilization perspective, coal mine gas is classified into four categories: (1) virgin coalbed methane or pre-mining degasification, (2) coal mine methane or degasification of working seams, (3) ventilation air methane, (4) abandoned mine methane. It is useful to explore the entire range of uses for all forms of coal mine gas to maximize the viability of each opportunity. Coal mine gas utilization/mitigation technologies are divided into five board categories: natural gas substitution, direct use at or near the mine site, electricity generation and cogeneration, chemical feedstock and simple destruction. Opportunities of implementation of these options in India have been discussed in this paper. This study will help to motivate both applied and theoretical research work on coal mine gas sites in India and after detailed analysis, it will provide basic data to interested industries.

Developing basin-specific emission factors for accurate methane inventory and emission reduction strategies in Zonguldak Coal Basin, Turkey: Implications for enhancing safety and sustainability

Long-term continuous monitoring of coal mining activities is conducive to master the development and potential risk factors of the mining area. Radar reflected echo signal contains the intensity and phase information, which is suitable for detecting different types of mining areas. However, relevant coal mining detection research mainly focuses on phase information, which results in the application based on underground coal mines more than open-pit coal mines. In order to take full advantage of Synthetic Aperture Radar (SAR) data, in this paper, a novel mine detection method based on intensity and phase information is introduced to detect the underground and open pit coal mine using the multi-temporal ALOS data in Shenmu County, China. Firstly, Interferometric SAR (InSAR) technology is used to detect the deformation information caused by underground coal mine. Secondly, the coherence information is used to detect the deformation from both underground and open-pit coal mine. Moreover, change detection method based on intensity information is used to detect the open-pit coal mining. Finally, the results of phase, coherence and intensity are combined to detect the underground and open-pit coal mine. The experimental results of Shengdong mine show the effectiveness of the proposed method.

Characteristics of coal mine ventilation air flows

With the expansion of the coal mining depth and scales, the content of coal mine methane (CMM) is increasing, bringing the great challenge to the safe coal mining and greenhouse gas control. Researching CMM emission laws and its drainage technologies in underground coal mining is essential. This paper analyzed the sources of CMM emission in the workface and then put forward the grid method to measure the CMM emission laws in the single coal seam, which error was verified by the integral method. The CMM emission laws of the S2107 workface of the Yuwu mine, northeastern Qinshui basin, China were researched as a case study and it is found that the upper corner was the key position of CMM control in the workface. The sub-source CMM drainage methods by the strike high-level roadway and long vertical buried pipes were applied against the different CMM sources in the S2107 workface. The gas concentration in the return air was less than 0.6% during the CMM drainage, verifying the effectiveness of the sub-source CMM drainage methods.

Fugitive Methane Emissions from Indian Coal Mining and Handling Activities: Estimates, Mitigation and Opportunities for its Utilization to Generate Clean Energy

In the United States, an unexpected and severe increase in coal miners’ lung diseases in the late 1990s prompted researchers to investigate the causes of the disease resurgence. This study aims to scrutinize the effects of various mining parameters, including coal rank, mine size, mine operation type, coal seam height, and geographical location on the prevalence of coal worker's pneumoconiosis (CWP) in surface and underground coal mines. A comprehensive dataset was created using the U.S. Mine Safety and Health Administration (MSHA) Employment and Accident/Injury databases. The information was merged based on the mine ID by utilizing SQL data management software. A total number of 123,589 mine-year observations were included in the statistical analysis. Generalized Estimating Equation (GEE) model was used to conduct a statistical analysis on a total of 29,707, and 32,643 mine-year observations for underground and surface coal mines, respectively. The results of the econometrics approach revealed that coal workers in underground coal mines are at a greater risk of CWP comparing to those of surface coal operations. Furthermore, underground coal mines in the Appalachia and Interior regions are at a higher risk of CWP prevalence than the Western region. Surface coal mines in the Appalachian coal region are more likely to CWP development than miners in the Western region. The analysis also indicated that coal workers working in smaller mines are more vulnerable to CWP than those in large mine sizes. Furthermore, coal workers in thin-seam underground mine operations are more likely to develop CWP.

Closely-spaced outburst coal seams (COCS) is the main condition of coal seams in southwest China, and gas disasters are one of the major problems affecting coal mine safety. Mining a protective seam and pre gas extraction are the most safety way to improve the efficiency of mining under these conditions. However, low pre-mining gas extraction efficiency coupled with the close proximity of adjacent working faces is a problem. When mining at an old working face has been completed but the new working face is not yet ready to be mined, coal-bed gasses can flow into the new working face from adjacent seams and this commonly causes methane monitoring instruments to sound an alarm. These gas extraction difficulties lead to a conflict between mine safety and profit. To solve these problems, a sequential approach for integrated coal and gas mining of closely-spaced outburst coal seams is introduced in this paper. Two fundamental principles are proposed: (1) Fully coordinating the spatiotemporal relationships between gas extraction, roadway development, and coal mining to maximize both mine safety and coal and gas production; (2) Defining a mining sequence for outburst coal seams and choosing the coal seam with the weakest outburst risk as the protective seam. A system for comprehensive gas extraction in underground coal mines is divided into four stages for gas extraction: gas extraction before coal roadway tunneling, gas extraction before coal mining, gas extraction during coal mining, and gas extraction from the goaf after coal mining. The Songzao mining area, China, is used as a case study to demonstrate the effectiveness of this model, and it brings three major benefits: it improves underground coal mine safety with physical gas accidents decreased by 66.8%, it makes underground coal-bed methane (CBM) extraction more efficient with the average gas extraction rate were respectively 45.13 m3/t and 62.4%, the highest in China, and it reduces greenhouse gas emissions equivalent to 3.5 million tonnes of carbon dioxide. This study could be used as a valuable example for other coal deposits being mined under similar geological conditions.

Utilization of Ventilation Air Methane in Indian Coal Mines: Prospects and Challenges

Study of efficiency and productivity growth in opencast and underground coal mining in India: a DEA analysis