scholarly journals Underground exploitations inside safety pillar shafts when considering the effective use of a coal deposit

2015 ◽  
Vol 31 (3) ◽  
pp. 93-110 ◽  
Author(s):  
Anton Sroka ◽  
Stanisław Knothe ◽  
Krzysztof Tajduś ◽  
Rafał Misa
Keyword(s):  
Underground Mining ◽  
Coal Bed ◽  
Building Structure ◽  
Coal Deposit ◽  
Continuous Increase ◽  
Continuous Miner ◽  
Safety Pillar ◽  
Mining Companies ◽  
Integral Methods ◽  
Effective Use

Abstract Underground mining exploitation creates damage in surface building structure and in underground constructions as well. For this reason, many mining companies gave up carrying out excavations in safety pillar shafts. Currently, the situation on the market is changing. The continuous increase in excavation depth combined with an increase in exploitation costs resulted in many mining companies trying to find cheaper solutions. One of the methods is to carry out partial exploitations inside safety pillar shafts. Such exploitation is much cheaper than ordinary, because it decreases the exploitations depth, the length of transportation drifts, etc. The functionality of the shaft and its infrastructure have to be fulfil. The authors present a methodology for calculating the effects of mining on mine shafts using geometric integral methods. The paper presents the assumption of the first method developed by Bals (1939), a method based on the so-called Professor Knothe Theory (1951) and the German method of Ruhrkohle (Ehrhardt and Sauer 1961). Based on these methods, operational planning rules are given for mining in protective pillars during coal bed exploitation; additionally, the dimensioning method for shaft pillars is specified. Presented solutions are illustrated with examples from mining practice, where the continuous miner system was planned in the direct area of the mining shaft.

The Model of Land Surface Movements Induced by Groundwater Rebound in the Area of Former Mining Exploitation

2021 ◽  
Author(s):  
Artur Guzy ◽  
Wojciech Witkowski ◽  
Ryszard Hejmanowski ◽  
Agnieszka Malinowska
Keyword(s):  
Land Surface ◽  
Mine Drainage ◽  
Underground Mining ◽  
Total Duration ◽  
Time Factor ◽  
Land Uplift ◽  
Continuous Increase ◽  
Aquifer System ◽  
Groundwater Head ◽  
Groundwater Rebound

<p>The objective of the research was to investigate the process of rock mass recompaction related to groundwater rebound induced by underground mining. Research has been conducted in the area of the closed copper ore mine (Konrad) as well as the anhydrite and gypsum mine (Lubichów) in south-eastern Poland.</p><p>The mining operation was carried out in the years 1944-2001 in the area of the Konrad mine and 1944-2015 in the area of the Lubichów mine. It resulted in substantial land subsidence of up to 1.4 m and drainage of the aquifer system. However, it is estimated that the subsidence caused by groundwater pumping during these periods was 0.3 m in total. Furthermore, the spatial extent of the depression cone in the aquifer system immediately after the cessation of exploitation significantly exceeded the limits of the mining areas. Following the closure of the mine, a continuous increase in the groundwater head and land uplift is observed.</p><p>Classical survey results and the Persistent Scatter Satellite Radar Interferometry (PSInSAR) method were used to determine land surface movements in the period from November 2015 to November 2020. The results of the research show in the area of the Lubichów mine closed in June 2015, vertical land uplift reached a maximum of approx. 92 mm in that period. At the same time, in the Konrad mine area, closed in March 2001, no significant land uplift was observed. However, the main part of the investigation concerned the development of a novel method of land uplifting prediction. As a result, an attempt was made to comparatively analyze the dynamics of land uplift associated with the life cycle of the mine and the increase in the groundwater head.</p><p>These analyzes allowed the time factor for the modelling of the land uplift to be determined. This time factor is approx. 5 months in the area of the Lubichów mine and indicates that there is a time lag between the start of the groundwater head increase and the land uplift occurrence. Also, the investigation revealed that land uplift will occur in the analyzed area for the next five years. However, the dynamics of such movements will gradually decline in the years to come.</p><p>The methodology developed could be applied to any post-mining area where groundwater rebound-related uplifts are observed. It may be an appropriate tool for estimating both the time during which the land uplift is expected to begin after the mine drainage has been stopped, as well as the total duration of the land uplift phenomena.</p>

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

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.

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

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.

scholarly journals Assessment of Heating and Cooling of a Spontaneous Fire Source in Coal Deposits—Effect of Coal Grain Size

Minerals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 907
Author(s):  
Marek Więckowski ◽  
Natalia Howaniec ◽  
Adam Smoliński
Keyword(s):  
Carbon Monoxide ◽  
Hazard Assessment ◽  
Fire Hazard ◽  
Temperature Drop ◽  
Coal Bed ◽  
Coal Deposit ◽  
Fire Source ◽  
Heating And Cooling ◽  
Spontaneous Fire ◽  
The Impact

Fire hazard assessment in coal mines is performed on the basis of concentrations of particular gases emitted from the heating coal deposit, but more precise criteria and indicators are needed to assess fire hazard properly—both during the temperature rise phase and in the coal bed cooling phase. In the paper the impact of coal grinding on hazard assessment of spontaneous fire development in the coal deposit during heating and cooling the fire source was analyzed. The intensity of desorption of ethane, ethylene, propane, propylene, acetylene, carbon monoxide and hydrogen is the resultant of temperature and grinding of coal samples. The results proved that the ratio of concentrations emitted by standard versus coarsely crushed coal for each of the gases, changed both in the growth phase as well as in the temperature drop phase. It was found that as the temperature rose, the effect of coal grinding on the release of ethane, ethylene, propane, propylene and carbon monoxide decreased. The greatest effect of coal grinding was observed in the case of ethane and propane, while the lowest in the case of hydrogen and carbon monoxide.

scholarly journals Intensive underground mining technologies: Challenges and prospects for the coal mines in Russia

2021 ◽  
pp. 60-69
Keyword(s):  
Coal Mining ◽  
High Performance ◽  
Underground Mining ◽  
Strain Analysis ◽  
Environmental Indicators ◽  
Mining Equipment ◽  
Underground Coal Mining ◽  
Mining Operations ◽  
Mining Companies ◽  
Production Growth

The article presents the key features of underground coal mining that influence the development of mining technologies and mining equipment design. It covers the most important challenges faced by underground coal mining companies and discusses growth areas in mining technology that are aligned with the paradigm of sustainable development. Using the example of underground coal mining operations, it illustrates such concepts as the intelligent mine and the invisible mine, discussing how they can be brought to life. It also shows how underground coal mining companies can improve their productivity, OSH management, and environmental indicators to make their products competitive. As mining operations are becoming more intensive and the average depth of mining is growing, which is accompanied by an increase in both methane emissions and risks associated with rock mechanics processes, it is becoming vital to accurately predict how the rock mass will behave and, by applying stress-strain analysis, to identify hazardous zones and their boundaries. The article discusses several mine layouts and how their parameters are adjusted to ensure intensive mining. Among the factors that hinder growth in coal production, it highlights the underutilisation of high-performance mining equipment. It also contains a list of key principles aimed at fostering production growth in the underground coal mining sector and improving its competitiveness.

Study on Contraction of Dust Control System in Continuous Coal Mining

2013 ◽  
Vol 734-737 ◽  
pp. 824-827 ◽  
Author(s):  
Yu Hui Ren ◽  
Yue Ping Qin
Keyword(s):  
Control System ◽  
Coal Mining ◽  
Field Testing ◽  
Point Of View ◽  
Dust Control ◽  
Continuous Miner ◽  
Control Models ◽  
The Face ◽  
Effective Use

Most of the dust control models indicate the line-curtain air reaching the face is limited and does not extend. Lower air quantity at the face helps in containing and concentrating the dust close to the face where no occupations are present. Hence, effective use of hydraulic sprays and directing the face dust-laden air into the scrubber may improve dust control. In this paper, we put forward a field testing of the modified scrubber-modified continuous miner demonstrated significant improvements in visibility and dust and quartz reduction, as compared to what was achieved with the current scrubber-current continuous miner dust control system. This is unfavorable from methane dilution point of view but can be used to advantage for improved dust control.

scholarly journals Influence of chosen technical constraints on stability of 3D geological model-based schedule in a complex longwall operation

2019 ◽  
Vol 123 ◽  
pp. 01024
Author(s):  
Leszek Malinowski
Keyword(s):  
Underground Mining ◽  
Geological Model ◽  
Coal Deposit ◽  
Mining Operations ◽  
Coal Deposits ◽  
Geological Models ◽  
Base Scenario ◽  
Mine Workings ◽  
Made In ◽  
Test Schedule

In Polish underground mining digital 3D geological models and mine structure models are becoming popular as an aid in creating design and schedules of mine workings. Article highlights development made in generating and optimizing mining operations. Having created a model it is possible to test schedule scenarios using a number of constraints. One of the constraint limiting coalmines is ventilation, which may be magnified by high content of methane in coal deposits. In this article two methods of introducing ventilation constraints have been presented. One limits number of longwall shearers working simultaneously in excavations ventilated by the shaft. The other limits tonnage of coal which can be extracted in each ventilation zone. Scenarios governed by the second method turned out to result in more stable exploitation than a base scenario. More precise calculations are possible if a model contains an accurate prognosis of methane emissions that would be caused by extraction of the coal deposit. The aim of the paper is to present possibilities of analysing and upgrading mining operations with the help of digital solutions.

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

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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