Coal Mining System Research Articles

Research on Centralized Short-Circuit and Leakage Protection for High-Voltage System of Underground Central Substation

According to the problems which are relay protection is difficult to adjust and when line fault occurs it will easily get override trip in the underground 6 kV power supply system in Gu Shu-yuan Coal Mine. This paper presents a centralized selective short circuit and leakage protection system. Which focuses on the analysis of the short circuit longitudinal differential protection, based on pattern recognition method of single-phase earth leakage protection principle, and completes the rapidity and selectivity of the leakage fault line selection . Through the simulation, experimental and field operation shows that the schemes can effectively improve the reliability and safety of high voltage power supply system in Gu Shu-yuan Coal Mine ,it also establishes the necessary foundation of the goal of "network relay protection" in high voltage power supply system for in China.

Research on Remote Condition Monitoring System in Coal Mine

In this paper, the signal sources of communication system are described in coal mine firstly, and then a kind of remote condition monitoring system based on the OFDM technology is presented. This system makes wire communication combined mutually with wireless communication by tandem adapter. Wireless communication is used in mining area or in the time of sudden accident, Power line or fiber-optic is used in main lane. This system makes use of the advantage of OFDM technology to provide many kinds of access service in mine. There are different grades and different rates for many consumers at the same time in these access services. The different modulation methods of sub-carries in this system increase flexibility and adaptability. The system not only fulfils the usual demand of produce communication monitoring, but also considers sudden accident, attains the state where the mining area arrives where the signal transports. This paper analyzed feasibility of the system based on some simulation tests finally.

Methane Risk Assessment in Underground Mines by Means of a Survey by the Panel of Experts (Sope)

The purpose of the paper was to develop a method of methane risk assessment in order to fulfil the technical-organizational and legal requirements for occupational risk assessment in mines. Methane hazard and associated risks of the effects of ignition and/or explosion of methane is one of the most severe natural hazards. Heuristic methodology based on the Delphi approach and a group survey by a panel of experts, which was named SOPE, was used to assess the magnitude of methane risk. The adopted tools for assessing the current state of methane risk factors and their possible accident consequences were targeted surveys, with the participation of experts representing, mainly, engineering-technical personnel of mine ventilation service. The objectivity and independence of the judgment of the experts was checked by determining indicators of the degree of the experts’ unanimity, indicators of their competence as well as indicators of the validity of their evaluations. The subject matter of the study of methane hazard were five longwall are- as of the “A-Z” twin-mine (after the merge of two mines: Mine A and Mine Z), three longwalls operated towards plant A and two longwalls operated towards plant Z. For the assessment of each area of the mine, a Methane Risk Assessment Questionnaire consisting of 4 assessment cards, was used. The cards included four areas of the studied risk factors, i.e. factors shaping the methane hazard (17 factors), the activity of the methane ignition initiators (19 factors), detection and prevention of methane risk (16 factors) and possible human and material losses (13 factors). The evaluation of 65 factors affecting the causes and consequences of the methane risk in the exploitation area under analysis, was conducted in accordance with the procedure of the adopted method, based on the proposed algorithm. Assessments by experts were used to calculate the indicators of the magnitude of methane hazard for each group of factors separately. A practical example of the application of this method is incorporated in chapter four of this paper, which also discusses the results of the conducted research. The obtained values of the indicators of methane risk assessment and analysis of their changes showed that the proposed method can be an important element in the design and construction of a modern methane safety system in coal mines. It provides the possibility of controlling this risk and enables the minimization of its consequences in accordance with the criteria of their acceptance, adopted in this paper. The method does not replace the currently used methods of methane risk assessment, but complements them in a significant and modern way.

INDUSTRIAL TESTS OF WASTE ROCK DIRECT BACKFILLING UNDERGROUND IN FULLY MECHANIZED COAL MINING FACE

For efficient, economical and environmentally disposing the waste rock underground, based on principles of waste direct backfilling in fully mechanized coal mining, this paper carries out a field test in 6304-1 working face of Jining No.3 Coal Mine. We first design a waste rock direct underground processing system, including screening-crushing system, transportation system, transfer system, stope backfilling system and coal mining system. Then optimize the waste backfilling and coal mining technology, update the waste backfilling process with start backfilling from backfill scraper conveyor s head to tail, gradually uplift tamping arm, gradually compact backfill materials, move backfill scraper conveyor forward when the tamping arm can t extend out and last fill roof gap by up material pushed by down material . At last, imply this system and check strata movement controlling effect by actual measuring the roof dynamic change law, which supported by the dense backfill body. The results show that the test working face can cut 0.6 million tons of raw coal one year, and direct backfill 0.74 million tons of waste rocks at the same time, and the maximum subsidence of immediate roof observed in situ is 340mm, the maximum caving speed is

Research on Water Monitoring System of Coal Mine Based on Ontology

With the exploitation of coal, the water pollution is increasingly severe. The quality of waste water treatment becomes the key point to the sustaining exploitation of coal resources .According to the need of coal mine water monitoring, the water monitoring system based on internet of things is designed. The system contains: data collection, data transmission, data storage and data inference. By ontology, the model foundation and deduction of the monitor data are both carrying on to realize the intelligent management on the coal mine water.

Possibility of applying mechanized coal mining in the mine 'Soko', with the comparative advantages of production results and impact

Mining method applied in the RMU 'Soko', is repeatedly technologically modified and reached the maximum limit in terms of productivity, level of job performance and safety at work. And all the other methods, which are in the technological process of obtaining coal rely on the technology of drilling-blasting works, in terms of the mine 'Soko', can not allow mass production of coal, regarding natural and technical-technological conditions prevailing in Sokobanja coal basin. Therefore, this paper proposes a possible solution which would enable a significant increase in annual production by appling mechanized coal mining system.

Radiation Disturbance of Variable Frequency Winch Drive System in Underground Coal Mines

In order to study the effect of variable frequency drive system upon electromagnetic radiation environment in underground coal mines, the mechanism of electromagnetic radiation from the variable frequency speed regulation system has been analyzed deeply, and the radiated electromagnetic noise from the variable frequency winch system with rated voltage of 1140V in underground coal mines has been measured. The measuring results show that the radiated emission from variable frequency drive system has certain effects on electromagnetic radiation environment in underground coal mines. The maximum radiated E-field strength reaches 123dBμV/m within the range of 9kHz to 20MHz nearby the frequency converter, and radiated E-field strength is no more than 33dBuV/m above 20MHz. Nearby the winch motor, the radiated E-field strength is weak, but the frequency spectrum of radiated E-field noises is more wide, which mainly distributes from 20MHz to 1GHz, but the maximum radiated E-field strength is less than 37dBμV/m above 20MHz.

Identification of Security Status of Production Logistics System in Coal Mine Based on RS–SVM

Identification of Security Status of Production Logistics System in Coal Mine Based on RS–SVM

Calculation Model of Safety Level of Production Logistics System in Coal Mine

Calculation Model of Safety Level of Production Logistics System in Coal Mine

Environmental impact on the magnetic field distribution of a magnetic proximity detection system in an underground coal mine

A magnetic proximity detection system mounted on an underground mobile mining machine detects whether a worker is hazardously close to the machine. The system generates magnetic fields covering the extended spaces around the machine. A magnetic detector worn by the worker measures the magnetic field flux density and determines the distance from it to the machine. The system is frequently in close proximity to coal as the machine moves, causing the magnetic field flux, in part, to enter massive in situ coal. This has the potential to have an adverse effect on the accuracy of the system and on the safety of the worker if the coal were to significantly alter the magnetic flux density distribution. Two experiments were conducted to study the impact of in situ coal on these magnetic fields. Measurements in one mine show that coal mass has no significant impact on the magnetic field flux distribution.

Simulation and Analysis of the Neutral Resistance Grounding of 1140V Power System in Coal Mine

The neutral grounding mode through resistance and the grounding resistance value of 1140V coal mining distribution system are studied and simulated in this paper. According to the 1140V power supply system parameter of the underground mining area of a coal mine, the PACAD software is used to establish the simulation model of power system. The single-phase ground fault caused by the insulation deterioration of the load equipment is simulated through setting single-phase ground fault in charge line of load side. The advantage of neutral grounding mode through resistance is analyzed through the simulation result. According to the distributed capacitance over the ground of simulation data and power network, the value range of the neutral point grounding resistance can be obtained.

Research on the Intelligent and Strong High-Voltage Power Supply System of Hu Sheng Coal Mine

The optimization program of intelligent and strong power supply system in coal mine is put forward on the basis of the Hu Sheng coal power supply system status. It achieves intelligent and integrated protection and real time monitoring dynamic process of supply network system based on WAMS; at the same time it achieves rapidity and selectivity of leakage protection based on the principle of pulse-polarity and RE identification method. And the program can prevent grade-skip trip, improve the mobility and reliability of mine supply system.

Grounding Effect on Common Mode Interference of Underground Inverter

For the neutral point not grounded characteristics of underground power supply system in coal mine, this paper studied common mode equivalent circuit of underground PWM inverter, and extracted parasitic parameters of interference propagation path. The author established a common mode and differential mode model of underground inverter. Taking into account the rise time of PWM, the simulation results of conducted interference by Matlab software is compared with measurement spectrum on the AC side and motor side of converter, the difference is consistent showing that the proposed method has some validity. After Comparison of calculation results by Matlab simulation ,it can be concluded that ungrounded neutral of transformer could redue common mode current in PWM system, but not very effective, the most efficient way is to increase grounding impedance of inverter and motor. DOI: http://dx.doi.org/10.11591/telkomnika.v11i9.3267

Research and Application of Ventilation Simulation and Monitoring System in Chensilou Coal Mine

Mine ventilation simulation system is a set of advanced, reliable and practical ventilation simulation system, which has a function of ventilation system simulation and visualization. It solved the technical problems such as automatic establishment and management of the topological relations, automatic identification of diagonal connection and air distribution according to demand under fixed cut set. According to the complexity of ChenSiLou coal mine ventilation system, the detailed analysis research is carried on. Mine ventilation simulation system has a successful connection with the mine monitoring system, realizing the real-time monitoring and real-time query. The technology is taken to optimize and transform the ventilation system of the mine. To ensure that the optimization and transformation of the ventilation system of the mine are carried out successfully, it simulated the ventilation system reconstruction scheme of the mine .The final plan is determined and has obtained the good effect of field application.

Connotation and Technology System of Green Mining of Manganese Resources

Based on the green mining concept of coal mine, connotation and technology system of green mining of manganese resources were expound. According to the problems on the mining and utilization procedure of manganese resources, the green mining of manganese was suggested. It included the water preserving mining technology, reducing subsidence mining technology, non-waste mining technology, as well as comprehensive utilization technology of other associated resources. The main key issues were in-depth analyzed in this paper, and the recommendations for the further research and development were proposed.

Mine Multi-sensor Maximum Likelihood Estimation Data Fusion Algorithm

After an overall consideration of the differences in the measurement accuracy of various sensors, an improved algorithm based on consensus data fusion has been proposed, the measurement accuracy of which is reflected through weight coefficient. It is indicated in simulation that this approach can effectively reduce data variation extent when there is disturbance in sensors, improving fusion accuracy and anti-interference capability. This algorithm will be applied in the data fusion of temperature sensor, gas concentration sensor in intelligent monitoring system of coal mine.

Improvement of Analytic Hierarchy Process and its Application for Coal Mine Safety Assessment

The calculation of weigh value and consistency of the judgment matrix of analytic hierarchy process (AHP) were studied in this paper. And the study was applied for coal mine safety assessment. Due to the particularity and complexity of the coal mine environment, to make sure the comprehensive assessment for coal mine system safety, analytic hierarchy process was usually used. It is an important problem to solve the weight value and consistency of the judgment matrix when applying analytic hierarchy process. To obtain the weight value and ensure the consistence of the judgment matrix is the main research direction of AHP. The genetic algorithm was applied to calculate the weight value and the consistency of the judgment matrix. And fuzzy comprehensive evaluation method was applied to evaluate the safety condition of the coal mine system with the method of weight value solution in this paper. Case study shows that the calcuation resuts of applying genetic algorithm to calculate idnex weight value is better than additional methods.

Research on Key Technologies of Mining Accident Early Warning, Supervisory Control and Contingency Plan

Scientific accident emergency precaution can reduce the frequency and the level of mining accidents. In this paper, mine hazard sources reassessment, coal mine system reliability analysis, damage and lost estimate were proposed as basement of accident early warning, and the calculation methods were discussed furthermore. Then a three-tire architecture designed management system of accident was constructed ,which can provide reference information for supervisory control and contingency plan.

Quantifying the emission’s impact of coal mining activities on the environment and human health in process

Discharges and emissions in the coal mining process have a strong effect both on the environment and on human health. This problem is usually be a negative one and has only been recognized qualitatively, due to the lack of effective quantitative methods. Based on emergy theory and accounting methodology, a set of quantitative methods for accounting the environmental support due to pollutants emissions was first introduced. Then impacts on environment and effects on human health were quantified using the unified units. The results indicated that water pollutants caused more impacts on the environment than air pollutants did, i.e., more environmental contributions are needed to dilute and absorb water pollutants. The occupation of land caused by coal mining gangue waste stacking has led to a huge loss of environmental services over the years. Moreover, the potential damage on the human condition health caused by CO2 through climate change cannot be ignored. Finally, the impacts of mining activities on environmental and human health in unified units are shown to provide a quantitative insight into the disadvantage of coal mining. The comparable results of the method indicate the different influence of various pollutants and the contribution of ‘natural capital’ directly. This work is a part of ongoing thermodynamic input-output analysis and life cycle analysis of coal mining systems (which are in process.)

Key Problem Analysis of Crushing Station Set on End Slope under the Semi-continuous System in Surface Coal Mines

Key Problem Analysis of Crushing Station Set on End Slope under the Semi-continuous System in Surface Coal Mines