scholarly journals Hydrodynamic impact on coal mass before crossing the most outburst-prone coal seams

2019 ◽  
Vol 109 ◽  
pp. 00112
Author(s):  
Vasyl Vlasenko ◽  
Dmytro Zhytlonok
Keyword(s):  
Coal Seam ◽  
Experimental Studies ◽  
Coal Mass ◽  
State Enterprise ◽  
Coal Seams ◽  
Dynamic Activity ◽  
Hydrodynamic Impact ◽  
Gas Dynamic ◽  
Mine Workings ◽  
Hydrodynamic Effects

The results of experimental studies of hydrodynamic effects (HDI) in industrial conditions are given. The HDI is designed to reduce the gas-dynamic activity of the coal seam and the rocks surrounding it. HDI was applied to the coal seam before it crossed the mine workings. The conditions for the implementation of HDI in industrial conditions Separate Enterprise “Mine “Tsentralna” State Enterprise “Toretskvuhillia” are described. The results of HDI on coal seams m2 -“Tonkyi” and m3 -“Tovstyi” are given. The parameters of the HDI method for outburst-prone coal seam before its crossing by mine workings are corrected.

scholarly journals The results of monitoring of hydroimpulsive disintegration of outburst-prone coal seams using ZUA-98 system

2020 ◽  
Vol 168 ◽  
pp. 00068
Author(s):  
Vasyl Zberovskyi ◽  
Kostiantyn Sofiiskyi ◽  
Rishard Stasevych ◽  
Artem Pazynych ◽  
Jan Pinka ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Rock Mass ◽  
Coal Seam ◽  
High Frequency ◽  
Strain State ◽  
Monitoring And Evaluation ◽  
Dynamic State ◽  
Coal Seams ◽  
Gas Dynamic ◽  
Mine Workings

The paper represents the results of monitoring and evaluation of the efficiency of hydroimpulsive disintegration of outburst-prone coal seams in the stopes of development mine workings using a system of sound detecting facilities. Methods of acoustic emission control have been considered as well as the monitoring tasks to evaluate rock mass conditions before the procedure and after it inclusive of the results of sound accompaniment of hydraulic disintegration of the coal seam. It has been determined that the higher concentration of stresses within the rock mass is, the more efficient action of high frequency self-oscillations of cavitation transmitter is on both the fissuring and changes in gas-dynamic state of the coal seam. It has been recommended to apply a mode of impulsive fluid pumping under the conditions where coal seam is in the stress-strain state.

scholarly journals Methane gas hydrates influence on sudden coal and gas outbursts during underground mining of coal deposits

2020 ◽  
Vol 201 ◽  
pp. 01002
Author(s):  
Volodymyr Bondarenko ◽  
Olena Svietkina ◽  
Roman Lysenko ◽  
Baochang Liu
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Underground Mining ◽  
Coal Seams ◽  
Dynamic Activity ◽  
Gas Dynamic ◽  
Coal Deposits ◽  
Thermobaric Conditions ◽  
Coal And Gas Outbursts ◽  
Methane Gas Hydrates

The mechanism of gas hydrates formation in coal seams is studied in the paper, as well as their involvement is hypothesized in the sudden outbursts of coal and gas during underground mining of coal deposits. It has been substantiated and proved that one of the real reasons for subsequent outbursts is the formation of gas hydrates in coal as a type of secondary gas hydrate deposits. It has been also substantiated that, as a result of coal metamorphism, a large amount of gaseous hydrocarbons, mainly methane, is formed in the seam, which under certain thermobaric conditions leads to the gas hydrates formation. It has been experimentally proved that the mechanism of such inclusions formation between gas hydrate and coal is a result of strong chemisorption, which, when disturbing thermobaric conditions, leads to gas-dynamic activity of coal seams. It has been revealed that during the dissociation of gas hydrates, obtained in a medium of activated coals, twice as much gaseous methane is released. The research analysis indicates that the formation of natural gas solid solutions in coal pores under certain thermodynamic conditions and the natural humidity, characteristic of coal seams, is one of the causes of sudden coal and gas outbursts. The gas hydrates dissociation influences on the gas-dynamic activity of a coal seam and the formation of an outburst hazardous situation.

scholarly journals DYNAMICS OF GAS EMISSION FROM EXPOSED SURFACE OF GAS-BEARING COAL SEAMS HAVING MEDIUM THICKNESS

2021 ◽  
Vol 13 (3) ◽  
pp. 441-448
Author(s):  
Nikolai KACHURIN ◽  
◽  
Galina STAS ◽  
Alexander KACHURIN ◽  
◽  
...  
Keyword(s):  
Coal Seam ◽  
Mathematical Models ◽  
Driving Forces ◽  
Mathematical Physics ◽  
Gas Release ◽  
Coal Seams ◽  
Excessive Pressure ◽  
Methane Release ◽  
Mine Workings ◽  
Gas Bearing

The goal of the research was to clarify the regularities of the dynamics of gas release from the surface of the outcrop of the developed coal seam. The main research methods were theoretical methods of mathematical physics and non-equilibrium thermodynamics. Gas-bearing coal seams are usually mined underground. When driving development workings, outcropping surfaces of gas-bearing coal seams appear and gases in the seams under excessive pressure are released into the atmosphere of the mine workings. Gas-bearing coal seams are usually mined underground. When driving preparatory workings, surfaces of outcropping of gas-bearing coal seams arise and gases that are in the seams under excessive pressure are released into the atmosphere of the mine workings. The most important gas-dynamic characteristic of this process is the rate of gas release, which represents the volume of gases released from a unit area of exposure of a coal seam per unit of time. A generalized law of resistance for gas filtration in a rock mass is recommended, and a fairly rigorous thermodynamic substantiation is given. It is shown that the densities of gas mass flows in accordance with the postulate of their linear relationship with the driving forces are determined by the Onsager relation. The results obtained and their discussion is presented. Mathematical models are proposed for engineering calculations of the dynamics of methane release from the outcropping surface of medium-thick coal seams. The error of the adopted approximations does not exceed 3%. The intensity of methane release is directly related to the planogram of work in the working face. Analysis of this dependence indicates that during the extraction cycle, methane release increases due to an increase in the area of the gas-release surface. The main conclusions are as follows: mathematical modeling of the processes of gas movement in a porous sorbing medium using approximate mathematical models representing linearized equations of mathematical physics; the regularities of the dynamics of the rate of gas release from the surface of the outcrop of a gas-bearing coal seam is the theoretical basis for the mathematical description of the process of gas release; the use of a linearized hyperbolic filtration equation most accurately describes the processes of methane release from the outcropping surface of mined coal seams.

Hydro-splitting of coal seams for their effective degassing preparation through underground wells

2020 ◽  
pp. 15-25
Author(s):  
S. V. Slastunov ◽  
A. V. Ponizov ◽  
A. P. Sadov ◽  
A. M.-B. Khautiev
Keyword(s):  
Coal Seam ◽  
Hydraulic Fracturing ◽  
Underground Mining ◽  
Working Fluid ◽  
Coal Seams ◽  
Natural Systems ◽  
Zone Of Influence ◽  
Complex Technology ◽  
Improved Technology ◽  
Hydrodynamic Effects

The article is devoted to the issues of improving the complex technology of coal seam degassing based on its hydrodynamic treatment. The possible modes of implementation of the introduction of working fluid into the coal seam in the process of its injection through wells drilled from preparatory workings and specially sealed to a certain depth, which ensures minimization of breaks of working fluid into the mine. Studies have been carried out to optimize the main parameters of hydrodynamic effects. Rational values of the effective well length and injection volume are established. The expediency of achieving significant rates of injection of the working agent into the formation for the disclosure of natural systems of cracks in it is shown. The directions of increasing the efficiency of formation degassing are investigated. The effectiveness of the integrated reservoir degassing technology was evaluated based on the factors of increasing methane production from underground reservoir degassing wells drilled into the zone of influence of underground hydraulic fracturing wells, and the total methane removal over the entire period of reservoir degassing. The efficiency of improved technology of hydraulic fracturing in underground mining for factors reducing downtime pollution control equipment, gazoobilnosti stope and the productivity of coal mining in zones of intensive integrated reservoir degassing.

scholarly journals Experimental Studies about Characteristics of the Rocks Displacement and State of Bearing Pressure on the Haulage Roadway

2019 ◽  
Vol 105 ◽  
pp. 01008
Author(s):  
Duc Thang Pham ◽  
Hung Thang Hoang ◽  
Victor Vitcalov
Keyword(s):  
Rock Pressure ◽  
Roof Rock ◽  
Experimental Studies ◽  
Coal Seams ◽  
Coal Basin ◽  
Mining Depth ◽  
The Face ◽  
Mine Workings ◽  
Roof Rocks ◽  
Quang Ninh

Comprehensive studies were conducted using measuring stations to measure the rock pressure and displacements of the roof rocks in the mine workings adjacent to the face when extracting medium thick inclined coal seams with the use of longwall (seam 6 at the Quang Hanh mine of Quang Ninh coal basin, Vietnam). The results of the study show that the displacement of the roof rock on the parallel roadway increases sharply at a distance of 1 to 12 m to the face, varies from 20 to 40 mm when the mining depth of the coal seam is 200 m and the maximum rock pressure on the haulage roadway supports is located at a distance of 3–8 m ahead of the face and is from 14 to 16 tons ranges.

Labor safety and control of the working area state in the penals while mining steep coal seams by shield aggregates

2020 ◽  
pp. 47-64
Author(s):  
V.V. Zberovskyi ◽  
◽  
R.А. Ahaiev ◽  
K.K. Sofiiskyi ◽  
B.М. Dehlin ◽  
...  
Keyword(s):  
Coal Seam ◽  
Physical And Mechanical Properties ◽  
Dynamic State ◽  
Coal Seams ◽  
Gas Dynamic ◽  
Geological Conditions ◽  
Labor Safety ◽  
Sudden Outburst ◽  
District Change ◽  
And Control

In this article, circumstances and factors which can lead to a degraded labour protection and occurrence of emergency in a district are reviewed and analyzed on the example of an accident occurred at sudden coal-and-gas outburst in the panel face № 42-1146 m of the Tovstyi-Zakhid seam m3 in the Central Mine of the Toretsvukhillia Mining Company. In this article, state of equipment and its location in the district in accordance with the requirements of the safety rules, records of devices which monitor gas-dynamic state of the coal seam and operation of the shield aggregate are considered. Mining and geological conditions of the seam bedding and technological conditions of the district location within the working horizon; methane content in the air of the roadways in the district; change of coal physical and mechanical properties in the area of possible geological disturbance; results of control of the coal seam gas-dynamic state analyzed by acoustic emission parameters; and other risk factors that led to emergencies were studied. The decisions made for controlling possible area with geological disturbance impact which was detected in the horizons of 916 m and 1026 m on the basis of mining-graphic materials and data of geological study in the mining roadways adjacent to the panel No. 14 in the district 42-1146 m were analyzed. The order and sequence of the works established for eliminating consequences of the coal and gas sudden outburst and detecting zone with disturbed coal and outburst cavity were considered. On the basis of the results obtained, conclusions were made and actions were elaborated on preventing accidents at mining steep prone-to-outburst coal seams by the shield aggregates. It is recommended to continue the scientific research for the purpose of detecting zone with possible impact of discontinuous geological disturbance and plicate disturbed zones in the coal seams by the changed hardness of coal in the adjacent panel, and developing certain local measures on preventing gas-dynamic phenomena at mining steep prone-to-outburst seams by the shield aggregates. The objective of this work was to analyze state of the working area and labor protection and to study the conditions and factors which had led to the accident with serious consequences and emergency condition of the panel.

Experimental studies of the extraction mine workings in a very weak rocks

2019 ◽  
pp. 218-228
Author(s):  
I.A. Kovalevska ◽  
◽  
O.S. Husiev ◽  
V.H. Snihur ◽  
O.K. Malova ◽  
...  
Keyword(s):  
Experimental Studies ◽  
Weak Rocks ◽  
Mine Workings

scholarly journals Improvement Dependability of Offshore Horizontal-Axis Wind Turbines by Applying New Mathematical Methods for Calculation the Excess Speed in Case of Wind Gusts

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3085
Author(s):  
Konstantin Osintsev ◽  
Seregei Aliukov ◽  
Alexander Shishkov
Keyword(s):  
Computer Simulation ◽  
Wind Turbines ◽  
Experimental Studies ◽  
Offshore Wind ◽  
Approximation Schemes ◽  
Calculation Error ◽  
Strong Wind ◽  
Mathematical Methods ◽  
Wind Gusts ◽  
Gas Dynamic

The problem of increasing the reliability of wind turbines exists in the development of new offshore oil and natural gas fields. Reducing emergency situations is necessary due to the autonomous operation of drilling rigs and bulk seaports in the subarctic and Arctic climate. The relevance of the topic is linked with the development of a methodology for theoretical and practical studies of gas dynamics when gas flows in a pipe, based on a mathematical model using new mathematical methods for calculation of excess speeds in case of wind gusts. Problems in the operation of offshore wind turbines arise with storm gusts of wind, which is comparable to the wave movement of the gas flow. Thus, the scientific problem of increasing the reliability of wind turbines in conditions of strong wind gusts is solved. The authors indicate a gross error in the calculations when approximating through the use of the Fourier series. The obtained results will allow us to solve one of the essential problems of modeling at this stage of its development, namely: to reduce the calculation time and the adequacy of the model built for similar installations and devices. Experimental studies of gas-dynamic flows are carried out on the example of a physical model of a wind turbine. In addition, a computer simulation of the gas-dynamic flow process was carried out. The use of new approximation schemes in processing the results of experiments and computer simulation can reduce the calculation error by 1.2 percent.

scholarly journals Cooperative Control Mechanism of Long Flexible Bolts and Blasting Pressure Relief in Hard Roof Roadways of Extra-Thick Coal Seams: A Case Study

2021 ◽  
Vol 11 (9) ◽  
pp. 4125
Author(s):  
Zhe Xiang ◽  
Nong Zhang ◽  
Zhengzheng Xie ◽  
Feng Guo ◽  
Chenghao Zhang
Keyword(s):  
Coal Seam ◽  
Cooperative Control ◽  
Field Tests ◽  
Surrounding Rock ◽  
Deep Hole ◽  
Coal Seams ◽  
Thick Coal Seam ◽  
Structure Damage ◽  
Hard Roof

The higher strength of a hard roof leads to higher coal pressure during coal mining, especially under extra-thick coal seam conditions. This study addresses the hard roof control problem for extra-thick coal seams using the air return roadway 4106 (AR 4106) of the Wenjiapo Coal Mine as a case study. A new surrounding rock control strategy is proposed, which mainly includes 44 m deep-hole pre-splitting blasting for stress releasing and flexible 4-m-long bolt for roof supporting. Based on the new support scheme, field tests were performed. The results show that roadway support failure in traditional scenarios is caused by insufficient bolt length and extensive rotary subsidence of the long cantilever beam of the hard roof. In the new proposed scheme, flexible 4-m-long bolts are shown to effectively restrain the initial expansion deformation of the top coal. The deflection of the rock beam anchored by the roof foundation are improved. Deep-hole pre-splitting blasting effectively reduces the cantilever distance of the “block B” of the voussoir beam structure. The stress environment of the roadway surrounding rock is optimized and anchorage structure damage is inhibited. The results provide insights regarding the safe control of roadway roofs under extra-thick coal seam conditions.

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