SPECIFIC FEATURES OF UNDERGROUND MINING HOST ROCKS DEFORMATION IN NON-UNIFORM GEOTECTONIC STRESS FIELD WITH REFERENCE TO “URGALUGOL”, JSC, “SEVERNAYA” MINE, В12 COAL BED

A physical model of the process of underground ore mining is substantiated and it is shown that ensuring the geomechanical safety of subsurface development is associated with the technological capabilities of nature-like mining technologies for the reproduction of stable dy-namic structures in the lithospheric objects being worked out. A cognitive analysis of typical geotechnologies is carried out and it is shown that the modern geo-technological paradigm is based on the principles of combining in time the processes that generate a geomechanical dis-turbance in the lithosphere and the processes to overcome the consequences of this disturb-ance. The internally insoluble contradiction of this approach is revealed and it is shown that overcoming this contradiction opens up a very real prospect of creating a fundamentally new concept for the development of underground mining technologies based on the implementation of the global idea of nature-like technologies in the form of the concept of creating convergent mining technologies. With the use of the proposed and developed by prof. The Rodionov model of the lithosphere as a solid body with different-scale inhomogeneities performed a theoretical study of the features of the stress field development during the formation of inhomogeneities with variable volume and zero density and found that in this case, the conditions for the repro-duction of stable dynamic structures will be determined by processes on the external contour of inhomogeneities. This made it possible to substantiate the geophysical and geotechnological ideas of a new technological paradigm of subsurface exploration.

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Modeling of the stress-state longwall face during coal mining with the technology of roof management complete drop and stowing

MINING INFORMATIONAL AND ANALYTICAL BULLETIN ◽

10.25018/0236-1493-2020-61-0-99-106 ◽

2020 ◽

pp. 99-106

Author(s):

I. E. Mazina ◽

A. A. Stel’makhov ◽

L. F. Mullagalieva

Keyword(s):

Coal Mining ◽

Strain State ◽

Underground Mining ◽

Negative Impact ◽

Hydrological Regime ◽

Coal Bed ◽

Stress Strain ◽

Environmental Friendliness ◽

Modeling And Analysis ◽

Stress Strain State

Underground mining of coal deposits has a negative impact on all components of the environment. When developing a coal deposit, it is coal mining technology that determines the scale and consequences of the negative impact. Changes in the stress-strain state of the geo-environment can lead to a violation of the hydrological regime, increased gas emission from the host rocks, the initiation of gas-dynamic processes. Choice of roofing management technology - as a geotechnological method of natural and technical system management determines the environmental friendliness of coal mining and creates safety conditions. The article deals with the technology of roofing control during coal production. For this purpose mathematical modeling and analysis of stress-strain state of the bottomhole part of the coal bed for the conditions of S.M. Kirov is performed. As a result of modeling, two technologies of roof control were analyzed - complete caving and stowing. For the worked out clearing leaves filled with either caving rocks or stowing material, there are characteristic unloading zones in the massif to be worked and overworked, as well as pressure reference zones, which fall on the parts of the pillars associated with the lava. It was found out that the application of the stowing technology creates conditions for minimization of gravitational stresses in the geoenvironment, as well as significantly reduces the potential energy of form change.

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A Review of Technical Potential for Coal Production and Coal Degasification – A Conventional Source of Methane – In Nigeria

Energy & Environment ◽

10.1260/095830503764929677 ◽

2003 ◽

Vol 14 (1) ◽

pp. 59-67

Author(s):

Adepo Jepson Olumide ◽

Ayodele Charles Oludare ◽

Balogun Olufemi

Keyword(s):

Coal Seam ◽

Fossil Fuels ◽

Underground Mining ◽

Simple Calculation ◽

Gas Content ◽

Gelling Agent ◽

Coal Bed ◽

Natural State ◽

Mining Operations ◽

Inorganic Matter

Coal, a solid fuel in its natural state has been identified as one of the world's major fossil fuels. It is a compact, stratified mass of mummified plant debris interspersed with smaller amounts of inorganic matter buried in sedimentary rocks. The use of coal as an energy source can be dated back to the prehistoric times. Methane is associated with many if not all coal seams, and is the dreaded “fire damp” responsible for many pit explosions. Coal mines are designed to vent as much methane as possible. It is present in the pores of coal under pressure, released during mining operations and can be extracted through vertical well bores. This paper highlights the fact that pipeline- quality methane can be extracted economically from coal seems before and during underground mining operations. The stimulation method involves hydraulic fracturing of the coal seam by using water, sand and, a gelling agent in a staged and alternating sand/and no sand sequence. The purpose is to create new fractures in the coal seam(s). The cleating of the coal helps to determine the flow characteristics of the coal formation and is vital in the initial productivity of a coal-methane well. The simple calculation of gas-in-place is achieved by multiplying the gas content of the coal by net coal thickness, the density, and the aerial extent of the drainage. The method is claimed to be suitable for use in Nigeria and potential sites for coal bed methane extraction in Nigeria are identified.

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Stable isotope (δD, δ18O) data on the structural water of two sericite samples from the Cu-Au high-sulphidation deposit Chelopech, Bulgaria – a tentative study

Geologica Balcanica ◽

10.52321/geolbalc.50.3.65 ◽

2021 ◽

Vol 50 (3) ◽

pp. 65-74

Author(s):

Nikolay Piperov ◽

Sylvina Georgieva

Keyword(s):

Carbon Dioxide ◽

Mineral Assemblage ◽

Meteoric Water ◽

Underground Mining ◽

Alteration Zone ◽

Structural Water ◽

Thermal Fractionation ◽

Ore Mineralization ◽

Host Rocks ◽

Isotopic Measurements

The epithermal high-sulphidation Cu-Au Chelopech deposit is characterized by a well-developed and well-traceable hydrothermal footprint manifested in the volcanic host rocks. The economic ore mineralization is embedded in the strong silicification, included among the advanced argillic zone of alteration, smoothly transitioning to quartz-sericite alteration that evolves into widespread propylitics. The quartz-sericite alteration zone is accessible for exploration only in underground mining galleries and exploration drillings. The main mineral assemblage in this zone is quartz, sericite, pyrite, minor rutile/anatase and relics of apatite and feldspar. According to XRD data from the studied samples, sericite was defined as illite and muscovite/sericite 2M1 polytype. The abundance of heavy stable isotopes (D, 18O) in the structural water of two sericite samples is the object of this study. A special attention was paid to the separation of extraneous waters from the structural one by thermal fractionation. The extracted structural water was converted to hydrogen and carbon dioxide before the isotopic measurements. The obtained results, put into a δD vs. δ18O plot, indicate that sericite structural water is “heavier” than meteoric water, within uncertainty limits.

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HEAT EXCHANGE OF THE COAL BED WITH ENCLOSING ROCKS DURING UNDERGROUND COAL GASIFICATION

News of the Tula state university. Sciences of Earth ◽

10.46689/2218-5194-2020-2-1-301-308 ◽

2020 ◽

Vol 2 (1) ◽

pp. 301-308

Author(s):

N.M. KACHURIN ◽

◽

E.I. ZAKHAROV ◽

G.V. FRIDLENDER ◽

M.P. GANIN ◽

...

Keyword(s):

Coal Seam ◽

Coal Gasification ◽

Heat Fluxes ◽

Coal Bed ◽

Underground Coal Gasification ◽

Coal Deposits ◽

Technological Level ◽

Sufficient Degree ◽

Host Rocks ◽

Thermal Preparation

It is shown that heat leaving the chemical reaction zone due to heat conduction is spent on thermal preparation of the coal seam and heating of the host rocks. It has been suggested that, with a sufficient degree of accuracy, we can assume that the heat fluxes are perpendicular to the surfaces that transfer heat. This made it possible, combining the origin of coordinate axes with these surfaces, to develop a mathematical model of heat transfer of a gasified coal seam with host rocks. It is noted that the model of the integrated use of the coalcoal complex of coal deposits allows reaching a new technological level using underground coal gasification.

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Numerical simulation of the in situ stress in a high-rank coal reservoir and its effect on coal-bed methane well productivity

Interpretation ◽

10.1190/int-2017-0183.1 ◽

2018 ◽

Vol 6 (2) ◽

pp. T271-T281 ◽

Cited By ~ 11

Author(s):

Shuai Yin ◽

Airong Li ◽

Qiang Jia ◽

Wenlong Ding ◽

Yanxia Li

Keyword(s):

Stress Field ◽

In Situ Stress ◽

Coal Bed ◽

Coal Bed Methane ◽

Small Displacement ◽

Small Scale ◽

Burial Depth ◽

Single Well ◽

Coal Reservoir

In situ stress has an important influence on coal reservoir permeability, fracturing, and production capacity. In this paper, fracturing testing, imaging logging, and 3D finite-element simulation were used to study the current in situ stress field of a coal reservoir with a high coal rank. The results indicated that the horizontal stress field within the coal reservoir is controlled by the burial depth, folding, and faulting. The [Formula: see text] and [Formula: see text] values within the coal reservoir are 1–2.5 MPa higher than those within the clastic rocks of the roof and floor. The [Formula: see text]–[Formula: see text] values of the coal reservoir are generally between 2 and 6 MPa and increase with burial depth. When the [Formula: see text]–[Formula: see text] value is less than 5 MPa, production from a single well is high, but when the [Formula: see text]–[Formula: see text] value is greater than 5 MPa, production from a single well is low. In addition, the accumulated water production is high when the [Formula: see text]–[Formula: see text] value is greater than 5 MPa, demonstrating that a higher [Formula: see text]–[Formula: see text] value allows the hydraulic fractures to more easily penetrate the roof and floor of the coal seam. In coal-bed methane development regions with high [Formula: see text]–[Formula: see text] values, repeated fracturing using the small-scale plug removal method — which is a fracturing method that uses a small volume of liquid, small displacement, and low sand concentration — is suggested.

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A Model of Anisotropic Property of Seepage and Stress for Jointed Rock Mass

Journal of Applied Mathematics ◽

10.1155/2013/420536 ◽

2013 ◽

Vol 2013 ◽

pp. 1-19 ◽

Cited By ~ 6

Author(s):

Pei-tao Wang ◽

Tian-hong Yang ◽

Tao Xu ◽

Qing-lei Yu ◽

Hong-lei Liu

Keyword(s):

Rock Mass ◽

Stress Field ◽

Underground Mining ◽

Principal Direction ◽

Water Pressure ◽

Jointed Rock ◽

Jointed Rock Mass ◽

Surrounding Rock ◽

Metal Mine ◽

Roadway Stability

Joints often have important effects on seepage and elastic properties of jointed rock mass and therefore on the rock slope stability. In the present paper, a model for discrete jointed network is established using contact-free measurement technique and geometrical statistic method. A coupled mathematical model for characterizing anisotropic permeability tensor and stress tensor was presented and finally introduced to a finite element model. A case study of roadway stability at the Heishan Metal Mine in Hebei Province, China, was performed to investigate the influence of joints orientation on the anisotropic properties of seepage and elasticity of the surrounding rock mass around roadways in underground mining. In this work, the influence of the principal direction of the mechanical properties of the rock mass on associated stress field, seepage field, and damage zone of the surrounding rock mass was numerically studied. The numerical simulations indicate that flow velocity, water pressure, and stress field are greatly dependent on the principal direction of joint planes. It is found that the principal direction of joints is the most important factor controlling the failure mode of the surrounding rock mass around roadways.

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FEATURES OF SEDIMENTOGENESIS AS FORMATION FACTOR OF COAL-BED STRUCTURE OF EASTERN DONBASS AND THEIR DEVELOPMENT CONDITIONS

Геология и геофизика Юга России ◽

10.23671/vnc.2015.1.55239 ◽

2015 ◽

Author(s):

В.В. Трощенко

Keyword(s):

Key Words ◽

Small Amplitude ◽

Underground Mining ◽

Coal Bed ◽

Formation Factor ◽

Coal Seams ◽

Mining Conditions ◽

Tectonic Dislocations ◽

Sedimentation Conditions

Приведены результаты исследований влияния условий накопления осадков на формирование мало- амплитудной тектонической нарушенности и горно-геологические условия разработки угольных пластов There are adduced results of investigation of influence of sediments accumulation conditions on the formation of small-amplitude tectonic dislocations and mining conditions of coal seams. Key words: coal seams, coal-bearing deposits, sedimentation conditions, underground mining, mining conditions

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APPLICATION OF SEISMOTOMOGRAPHY METHODS FOR SOLVING VARIOUS PROBLEMS IN THE MINING AND GEOLOGICAL DIRECTION

Visnyk of Taras Shevchenko National University of Kyiv Geology ◽

10.17721/1728-2713.92.07 ◽

2021 ◽

pp. 50-54

Author(s):

A. Sadchikov ◽

N. Zhelaeva ◽

J. Tokusheva ◽

M. Ponomareva

Keyword(s):

Geological Structure ◽

The State ◽

Seismic Exploration ◽

Coal Bed ◽

Mountain Range ◽

Coal Basin ◽

Geological Conditions ◽

Tectonic Disturbances ◽

Host Rocks ◽

Karaganda Coal

The Karaganda coal basin is characterized by a complex structure. The presence of geological inconsistencies such as tectonic disturbances, washouts, variable reservoir hypsometry, etc. makes it difficult to conduct underground mining operations. Currently, in the world practice, mine seismic exploration is widely used for the purpose of studying the geological structure and solving various mining problems. Safe and productive operation of treatment faces in underground coal mining requires a timely and reliable forecast of the mining and geological conditions of the structure and condition of the coal-bearing mass from the mine workings. The most accurate and reliable picture of the tectonic structure of the Carboniferous massif can be obtained using methods of mine seismic exploration to study the geological structure and conditions of the coal bed and host rocks. The main goal of implementing modern methods of mine seismic exploration was to conduct mathematical modeling to assess the possibility of identifying tectonic disturbances with an offset amplitude of the order of magnitude and higher than the reservoir capacity using various methods of underground seismic exploration - the seismic transmission method (STM) and the reflected wave method (RWM). For this purpose, physical models of sections of the Carboniferous massif were developed, including a geometric description of geological structures, the distribution of rock densities, velocities, wave propagation and their influence on compression, and the shift of the mountain range. One of the models corresponded to a section of the formation without geological disturbances, and the second one - to a section with tectonic disturbances with displacement amplitudes from 5 to 15 m. The results obtained can be used in the development of modern effective methods for predicting the state of the mountain range in complex mining and geological conditions of both the Karaganda coal basin and other coal basins with a complex geological structure. Initially, seismic surveys were performed using the method of reflected waves using the common depth point method. However, the problem of obtaining an objective image of the geological environment is still relevant, due to the peculiarities of elastic wave excitation in mine conditions (features of the generated wave field, patterns of its propagation, the direction of the source). The method of mine seismic survey based on channel and boundary waves registration was developed and applied. This method allows obtaining a detailed geological and geophysical model of the field site. Due to the processing of both types of waves, the resolution of the method is increased to obtain information about both the coal bed and the host rocks, and, in particular, the state of the roof of the formation. The method of measurements in mine conditions is presented, the results of testing the method of performing field work in mine conditions are shown, and seismic characteristics with high contrast and clear traceability of reflecting boundaries are obtained.

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A study of dynamic adsorption of propylene and ethylene emitted from the process of coal self-heating

Scientific Reports ◽

10.1038/s41598-019-54831-6 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 3

Author(s):

Karolina Wojtacha-Rychter ◽

Adam Smoliński

Keyword(s):

Underground Mining ◽

Early Stage ◽

Coal Dust ◽

Fixed Bed ◽

Gaseous Mixture ◽

The Self ◽

Coal Bed ◽

Heating Process ◽

Constant Flow Rate ◽

Self Heating

AbstractThe gaseous products emitted in the self-heating process constitute one of the parameters suggested for detecting coal spontaneous combustion in underground mining. The objective of the study is to investigate the changes of ethylene and propylene content in a gaseous mixture which flowed through a fixed bed column filled with bituminous coal of different grain size. The mixtures of fire gases were obtained from laboratory simulated heating of coal at the temperatures of 373 K, 423 K, 473 K and 523 K. Hydrocarbons of various initial concentrations were introduced to the adsorption column at the constant flow rate of 2∙10−7 m3/s. The experimental findings show that decreasing the adsorbent granulation and gases concentration causes an extended breakthrough and coal bed saturation times. In all the tests, the saturation time was gained faster for ethylene than for propylene. Thus, the content of tested hydrocarbons, which are some of the indicators for assessing the degree of the coal self-heating process, in mine air may change in time as a result of the adsorption phenomenon. It occurs particularly at the early stage of the self-heating process and in places where coal dust has been left.

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