Papers by Keyword: Coal Mine

Abstract: During operation of coal mines, polluted air is emitted from the ventilation shafts, it contains large amount of carbon and rock dust with various physical and mechanical composition. Dust contains freshly formed silicon dioxide and other components of the mineral product that are hazardous to human health, which are scattered in the surface layer of the atmosphere. Mainly fine dust comes from the mine workings, and the release of the total dust mass by 80 – 96 % is due to the operation of the loading and unloading complex. It is established that the level of dustiness decreases mainly due to the settling in the mine workings of the coarsely dispersed dust fraction. The environment receives mainly fine dust with a high content of fine particles, which can be intensively dispersed outside the sanitary protection zone of the mine. A mathematical model is obtained in the form of a differential equation of mass transfer, which takes into account the physic and mechanical composition of the dust emission from the ventilation shaft of the coal mine as a factor of ecological hazard. The obtained results determine the directions of effective struggle against dust emissions of coal mines.

Abstract: H₂S gas would pose a threat to coal mine safety. This article from the biodegradation, microbial sulfate reduction, thermal decomposition chemistry, chemical sulfate reduction and magmatic 5 aspects to analyze the formation mechanism of hydrogen sulfide gas in coal mine, a coal mine combined with field data, analysis of hydrogen sulfide gas in the coal mining the transport mechanisms. Research for the comprehensive management of coal mine hydrogen sulfide gas has certain significance.

Abstract: Sulfur cycling based on biological oxidation of sulfide to sulfate involves sulfur-oxidizing reducing microbial communities associated with sulfide which normally oxidize sulfide in acidic environment to sulfate. The chemolithotrophic sulfur oxidizing bacteria (SOB) usually use organic and/ or inorganic sulfide initially oxidizing and subsequently released sulfate under aerobic or subaerobic condition. This study was to understand SOB community isolated from coal mine treating plant at Mae Moh, Lampang and their potentials in hydrogen sulfide (H₂S) removal. In this result, with common heterotrophic medium supplemented with glucose 10 mg/ L and sulfur 0.001%, the cultured SOB were successfully cultivated based on most probable number method. Their activity showed an increase in sulfate concentration over time correspondent to an increase in culturable SOB communities. The SOB community could also develop their own microbial niches in the present of continuously aerated H₂S in the medium at 30-40°C during 7 day incubation. They could remove H₂S between 200-500 ppm from wastewater. These sulfur oxidized H₂S contaminated in wastewater treatment facilities or drainage. Their species will be further isolated and characterized by molecular analysis.

Abstract: This research is focused on dynamic performance of water hydraulic single hydraulic prop, the mathematical and AMESim model of single hydraulic prop are established. And the drop hammer is introduced to simulate the impact load of the surrounding rock acting on the prop. The performance parameters of prop retract displacement and cavity pressure are used as the research objects. The working process of single hydraulic prop is reproduced by the simulation. And the influence of safety valve parameters on the support system is analyzed. The results show that: increasing maximal valve core stroke and dead volume or reducing valve damping hole diameter can improve the support performance of the single hydraulic prop. But the influence of equivalent damping has two sides. For support system, decrease damping can improve the support performance, but for the safety valve, reduce the damping make the valve core stability decline. In addition, the pressure overshoot of the optimized system is 18.3%, adjusting time is 0.5s and the retract displacement is 10mm. The dynamic performances meet the technology requirements of the coal mine safety production of China.

Abstract: This paper describes a Main control system of the mobile robot TELERESCUER for inspecting coal mine areas affected by catastrophic events. Carried out in a framework of a EU programme of the Research Fund for Coal and Steel under the grant agreement No. RFCR-CT-2014-00002. The main problem is to applicate the very demanding safe requirements of ATEX on the design of the control system including its communication with other robot subsystems. The solving of this problem is presented in this paper.

Abstract: Because of the complex geologic space body and the underground seepage conditions, it is difficult to predict groundwater water inflow in prevention and treatment control work of coal mine. To predict the groundwater flow of the coal seam under the roof sandstone aquifer in Nanshan coal, the big water well method and three-dimensional numerical model were used at the same time. The quantity of predicted normal water inflow was 553.5 m³/h by using numerical model and the big-well method is about 591.6 m³/h. The result of big-well methods was relatively close to the result of numerical simulation method, which proved the rationality of the two methods in parameters selection and model building, and greatly improved the reliability and accuracy of prediction results. Compared with large-well method, by establishing the complex 3D geological structure of underground water and fitting the parameters based on the actual data of hydrology, numerical method could simulate the process of groundwater seepage and dewatering engineering, overcome the parameter uncertainty of large-well method, improve the predictive accuracy of the mine water inflow, and has important application value.

Abstract: Grey forecast can master the developing law of system through dealing with incomplete information of system at present. On the basis of actual data of Feng Feng Coal Mine, the grey forecasting model for coal mine accidents due to human factor in Feng Feng by using the grey system theory in this paper, it is shown that models which are built have good precisions. Safety and production of Feng Feng Coal Mine are forecasted by using grey forecasting models which are built. The results show that the forecasting models will help coal mines to forecast accidents due to human factor next year and generally tally with development tendency of Feng Feng Coal Mine.

Abstract: In order to have more accurate analysis about the eruption period of gas eruption under a coal mine system, fractal geometry theory was introduced. Based on field test data, a novel R / S analysis method was used to calculate the Hurst parameter, which determined the persistence correlation of the gas system, and eruption period was calculated subsequently. The period was used by the coal mine factory to arrange the manufacturing process and for three years no accident about gas eruption under the coal mine was reported.

Abstract: The height of the water flowing fractured zone and the extent of water inrush caused by coal mining are the main influence factors on aquifer systems. Taking a coal mine of Shanxi province as research object, the impact of coal mining on regional surface water and groundwater was evaluated. The heights of the water flowing fractured zone of coal seams in No.3, No.8-2, No.15-1 and No.15-3 were 68.62~98.62m, 31.21~58.25m, 30.59~33.41m and 31.45~42.33m respectively. The results showed that the surface would not be penetrated and the surface water environment could not be impacted seriously. While the lower shihezi formation aquifer which was the mined-out area of coal seams in No.3 and No.8-2 would be penetrated. Coal seam in No.15-3 belongs to relatively safe area, which water inrush coefficient ranged from 0MPa/m to 0.0148MPa/m.

Abstract: Gas disaster and prevention is the critical issue in heading laneways of underground coal mine. There are two goals needs to meet, one is air quantity requirement and energy conservation during normal ventilation, the other is safety and quickly during gas outburst. Firstly, gas migration character and auxiliary ventilation system placements are described in detail. Since two control goals need to reach, a dual-mode fuzzy control strategy for auxiliary ventilation is established. Besides weight calculation method which harmonizes subjective and objective weight calculation is put forward. After then, a gas discharging experiment platform including PLC controller, converter and heading laneway simulation model is established on the basis of theoretical analysis and simulation results. Finally, experimental results have shown that the system can safely and efficiently fulfill the function both at normal ventilation and gas discharging.