scholarly journals The Impact of the Low Throw Fault on the Stability of Roadways in a Hard Coal Mine

2017 ◽  
Vol 39 (1) ◽  
pp. 63-72 ◽  
Author(s):  
Piotr Małkowski ◽  
Łukasz Ostrowski ◽  
Piotr Bachanek
Keyword(s):  
Fault Zone ◽  
Coal Mine ◽  
Geological Structure ◽  
Hard Coal ◽  
Convergence Results ◽  
Roadway Stability ◽  
Special Measuring ◽  
The Stability ◽  
Degree Of Convergence ◽  
The Impact

Abstract Ensuring roadways stability in hard coal mines is one of the main challenges faced by engineers. A changeable geological structure have caused the roadway’s conditions to vary, thus influencing its stability. One of the causes of those changes is the presence of a previously undiscovered fault zone (small faults crossed the roadway) within which a significant convergence or support deformation may occur. The paper presents the impact of low throw faults on the degree of convergence of roadways. Convergence is determined for two roadways in the hard coal mine. A special measuring stations have been installed in one of the roadways, and they have carried out constant measurements for 15 months. In the other roadway, the degree of convergence has been determined on the basis of an on-site verification and comparison of the measurements obtained and the initial values, based on the roadway’s records. On the basis of the obtained convergence results, the impact of a single fault and the entire fault zone on the roadway stability has been determined. The impact of a single, low throw fault results in a 30% higher vertical convergence than in the case of roadways free of geological disturbance. In the roadway section located in the fault zone, vertical convergence is 4 times higher than in the case of sections free of disturbance impact. The floor heaving constitutes ca. 90% of vertical convergence both for roadway sections situated within the faulted zones and for sections free of the influence of any additional factors.

scholarly journals The influence of the fault zone width on land surface vibrations after the high-energy tremor in the “Rydułtowy-Anna” hard coal mine

2018 ◽  
Vol 36 ◽  
pp. 02007 ◽  
Author(s):  
Elżbieta Pilecka ◽  
Dariusz Szwarkowski
Keyword(s):  
Rock Mass ◽  
Fault Zone ◽  
Seismic Wave ◽  
Coal Mine ◽  
Land Surface ◽  
High Energy ◽  
Hard Coal ◽  
Surface Vibrations ◽  
The Impact ◽  
Damage Risk

In the article, a numerical analysis of the impact of the width of the fault zone on land surface tremors on the area of the “Rydułtowy – Anna” hard coal mine was performed. The analysis covered the dynamic impact of the actual seismic wave after the high-energy tremor of 7 June 2013. Vibrations on the land surface are a measure of the mining damage risk. It is particularly the horizontal components of land vibrations that are dangerous to buildings which is reflected in the Mining Scales of Intensity (GSI) of vibrations. The run of a seismic wave in the rock mass from the hypocenter to the area’s surface depends on the lithology of the area and the presence of fault zones. The rock mass network cut by faults of various widths influences the amplitude of tremor reaching the area’s surface. The analysis of the impact of the width of the fault zone was done for three alternatives.

scholarly journals Impact of the Selected Disturbing Factors on Accuracy of the Distance Measurement with the use of Ultrasonic Transducers in a Hard Coal Mine

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 133
Author(s):  
Sławomir Bartoszek ◽  
Grzegorz Ćwikła ◽  
Gabriel Kost ◽  
Krzysztof Nieśpiałowski
Keyword(s):  
Coal Mine ◽  
Distance Measurement ◽  
Ultrasonic Waves ◽  
Ultrasonic Transducers ◽  
Hard Coal ◽  
Airborne Dust ◽  
Measurement Results ◽  
Legal Restrictions ◽  
Mine Roadways ◽  
The Impact

The article presents tests on the possibility of using ultrasonic transducers for accurate distance measurement in hard coal mines. In order to check the impact of selected disturbing factors on the measurement results, test stands were built, and then a full cycle of measurements with the use of different transducers (AR30 and AR41), which were selected and pre-tested in previous research projects, was realized. The impact of such disturbing factors as airborne dust (coal, stone, lime and mixed dust), changes in temperature and humidity on the propagation of ultrasonic waves, amplitude and measurement accuracy was investigated. The tests were preceded by theoretical analysis. It was found that the transducers selected for the tests had a sufficient accuracy and range, so they can be used in the devices planned to be designed, allowing for the determining of the location of a roadheader in hard coal mine roadways, taking into account technical and legal restrictions. It was also specified which disturbing factors should be compensated and what methods and parameters of this compensation should be used.

Trend Surface Analysis Method Applied in Coal Seam Structure in ZhuJiaHe

2015 ◽  
Vol 744-746 ◽  
pp. 686-689
Author(s):  
Xi Cheng Xue ◽  
Zhi Qi Wang
Keyword(s):  
Coal Seam ◽  
Surface Analysis ◽  
Coal Mine ◽  
Geological Structure ◽  
Mine Safety ◽  
Analysis Method ◽  
Trend Surface Analysis ◽  
Trend Surface ◽  
Surface Analysis Method ◽  
The Impact

Due to the impact of multi-period structure in Zhujiahe coal,Mine structure complicated and Has caused a certain impact on coal mine safety production. article Randomly selected 30 from 170 borehole date in coal mine.This paper analyzes 1, 2, 3 times of trend surface on No. 5-2 coal seam floor elevation.exploring the trend surface analysis method research in mine geological structure regular.

scholarly journals Discussion on support technology of coal mine soft rock roadway

2020 ◽  
Vol 9 (1) ◽  
pp. 21-22
Author(s):  
Xiaolei Chen ◽  
Keyword(s):  
Coal Mine ◽  
Soft Rock ◽  
Geological Structure ◽  
Deep Mining ◽  
Coal Resources ◽  
Roadway Support ◽  
Increasing Demand ◽  
The Stability ◽  
Soft Rock Roadway ◽  
Rock Roadway

China is rich in coal resources. In most cases, coal resources are obtained through the way of mining. In the process of mining, it is necessary to control the application of mining technology, otherwise it will easily cause damage to the geological structure. With the increasing demand of social resources in recent years, shallow mining has been unable to meet the needs of the society, while deep mining is facing the problem of soft rock layer, which can not guarantee the stability and safety. Based on this, this paper will focus on the coal mine soft rock roadway support technology.

scholarly journals Numerical Simulation Study on the Influence of Mine Earthquake on the Bolt Stress

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Xiaoqian Zhang ◽  
Heng Zhang ◽  
Chengmin Wei
Keyword(s):  
Safety Factor ◽  
Coal Mine ◽  
Axial Stress ◽  
Microseismic Monitoring ◽  
Earthquake Hypocenter ◽  
Mine Roadway ◽  
Bolt Stress ◽  
The Stability ◽  
The Impact ◽  
Bolt Support

Mine earthquake, as an underground disaster that occurs frequently, has a great impact on coal mine roadway and support. The stability analysis of the bolt support in roadway under different mine earthquake magnitudes is a key issue to be solved urgently in mining fields. This paper attempted to simulate the occurrence state of mine earthquake with explosive blasting process and verified it with actual coal mine microseismic monitoring data. ANSYS/LSDYNA software was used to analyze the impact of magnitude and location of mine earthquake hypocenter on the stability of bolt support and the dynamic stress characteristics of bolt. The results showed that with the increase in source energy of mine earthquake, the damage location of bolt mainly appears in the front of bolt and the loading position has no obvious change, but there is stress wave superposition effect, which deepens the damage of bolt. The bolts in the middle of the lane and the middle of the roof are greatly affected, so the support strength should be strengthened in these places. In addition, this paper compared the safety factor of bolt and the supporting effect of different schemes from three aspects such as roof subsidence, axial stress of bolt, and safety factor of bolt and then put forward a more economical and effective supporting scheme.

scholarly journals ENSURING THE STABILITY OF INTERNAL DUMPS ACCORDING TO THE RESULTS OF PHYSICAL AND MECHANICAL PARAMETERS OF SOILS

2021 ◽  
pp. 38-45
Author(s):  
Stanislav Stovpnyk ◽  
Tetiana Kosenko
Keyword(s):  
Slope Angle ◽  
Physical And Mechanical Properties ◽  
Stability Margin ◽  
Geological Structure ◽  
Fine Grained ◽  
Lower Tier ◽  
Stability Of Slopes ◽  
The Stability ◽  
The Impact ◽  
Selective Formation

Purpose. The paper considers the issues of ensuring the stability of internal dumps consisting of soft rocks. This issue is relevant because the stability of quarry boards and dumps affects the safety of work in quarries. Methodology. When assessing the stability of slopes, the method of determining the minimum coefficient of stability, equal to the ratio of restraining forces to shear forces that arise in the slope array. Findings. The calculation and assessment of the stability of the slopes of the dumps are carried out on the example of Malyshevsky rutile-zircon-ilmenite deposit. The geological structure of the deposit overburden is represented by loess-like loams, red-brown clays, gray-green clays, fine-grained sands. To ensure the stability of internal dumps, the selective formation of dumps is proposed, which is presented in this paper in two ways. In the first variant, the dumping of Sarmatian gray-green clays into the lower part of the heap, which are weakly permeable and have low strength, is considered. In the second variant, a layer of Sarmatian sands is poured into the base of the dump. According to the normative value of the coefficient of stability margin, depending on the physical and mechanical properties of the rocks that make up the array, the optimal height and slope angle of the dump are determined. When assessing the stability of the slopes of the dump, the impact of groundwater and the possibility of location in the developed space of the tailings were also taken into account. Originality and Practical implications. Studies have shown that the most rational option is the formation of internal heaps with embedding in the base of the lower tier of the heap with a height of 40 m layer of Sarmatian sands; in the case of embedding in the lower part of the inner heaps of gray-green clays, it is advisable to form the lower tier of the heap with 2 sub-tiers up to 20 m high; the upper tier of the dump is recommended to be formed by one massif 26 m high. Besides, in the produced space of the quarry, the location of the tailings is possible in case of dumping Sarmatian sands into the base of the dump.

scholarly journals Study on the Migration Law of Overlying Strata of Gob-Side Entry Retaining Formed by Roof Cutting and Pressure Releasing in the Shallow Seam

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Chen Tian ◽  
Anhu Wang ◽  
Yingjie Liu ◽  
Tinggui Jia
Keyword(s):  
Coal Mine ◽  
Vertical Displacement ◽  
Mechanical Analysis ◽  
Stability Control ◽  
Surrounding Rock ◽  
Hard Coal ◽  
Cutting Angle ◽  
Maximum Angle ◽  
Roadway Stability ◽  
Cutting Height

A mechanical model of a hard roof was built to analyze the pressure relief roof cutting (RCPR) process for gob-side entry retaining (GER) and identify the critical stage of roadway stability control during RCPR. Based on the mechanical analysis of key parameters of automatic roadway with RCPR, the FLAC3D software was adopted to conduct a numerical simulation to investigate the influence law of height and angle of RCPR, to analyze the trend of variations in the vertical displacement of roadway surrounding rock stress and the roof under different conditions, and to verify that the optimal roof cutting height and seam cutting angle of the 12201 working face of Halagou Coal mine are 6 m and 20°, respectively. The effect of automatic roadway with RCPR has been well implemented through conducting the bidirectional cumulative blasting test on site. To impose effective roadway surrounding rock controlling measures on Halagou Coal mine in RCPR of hard, coal-bearing roof structures at a shallow mining depth, constant resistance large deformation anchor cables, in combination with a single hydraulic prop, joist steel 11#, and steel mesh reinforcement, could provide active surrounding rock support. In addition to the active support, surrounding rock control could be strengthened using grouting bolts. Based on the result, the stress in the roadway coal side and the vertical displacement of the roof can be reduced through increasing the roof cutting height, contributing to the stability of the roadway. Increasing of the roof cutting angle will lead to the increasing of stress in the coal side of the roadway and the increasing of roof displacement with a maximum angle of 20°. Meanwhile, the peak of stress concentrating on both sides of the extreme angle is decreased. Thus, increasing the cutting roof angle at random can be unfavorable to the management of roadway roof. To develop RCPR GER, roadway surrounding rock requires greater support when the mine face passes through a cutting slot. After industrial trials, these measures are proved to be effective in controlling surrounding rock movement and developing GER.

Dietary Vitamin and Stability of Oral Anticoagulation: Proposal of a Diet with Constant Vitamin K1 Content

1997 ◽  
Vol 77 (03) ◽  
pp. 504-509 ◽  
Author(s):  
Sarah L Booth ◽  
Jacqueline M Charnley ◽  
James A Sadowski ◽  
Edward Saltzman ◽  
Edwin G Bovill ◽  
...  
Keyword(s):  
Dietary Intake ◽  
Vitamin K ◽  
High Performance ◽  
Case Reports ◽  
Food Composition ◽  
Dietary Guidelines ◽  
Dietary Vitamin ◽  
Vitamin K1 ◽  
The Stability ◽  
The Impact

SummaryCase reports cited in Medline or Biological Abstracts (1966-1996) were reviewed to evaluate the impact of vitamin K1 dietary intake on the stability of anticoagulant control in patients using coumarin derivatives. Reported nutrient-drug interactions cannot always be explained by the vitamin K1 content of the food items. However, metabolic data indicate that a consistent dietary intake of vitamin K is important to attain a daily equilibrium in vitamin K status. We report a diet that provides a stable intake of vitamin K1, equivalent to the current U.S. Recommended Dietary Allowance, using food composition data derived from high-performance liquid chromatography. Inconsistencies in the published literature indicate that prospective clinical studies should be undertaken to clarify the putative dietary vitamin K1-coumarin interaction. The dietary guidelines reported here may be used in such studies.

The Influence of Disintegration of Hard Coal Varieties of Different Metamorphism Grade on the Amount of Sorbed Ethane / Wpływ rozdrobnienia odmian węgla kamiennego o różnym stopniu metamorfizmu na ilości sorbowanego etanu

2013 ◽  
Vol 58 (2) ◽  
pp. 449-463 ◽  
Author(s):  
Mieczysław Żyła ◽  
Agnieszka Dudzińska ◽  
Janusz Cygankiewicz
Keyword(s):  
Sorption Isotherms ◽  
Electron Donors ◽  
Hard Coal ◽  
Coal Surface ◽  
Compact Layer ◽  
Compact Structure ◽  
Small Surface ◽  
Mining Works ◽  
The Impact ◽  
Content Of Oxygen

Ethane constitutes an explosive gas. It most often accompanies methane realizing during exploitation and mining works. In this paper the results of ethane sorption have been discussed on three grain classes of six selected hard coal samples collected from active Polish coalmines. On the basis of obtained results, it has been stated that the tested hard coals prove differentiated sorption power with reference to ethane. Te extreme amount of ethane is sorbed by low carbonized hard coal from “Jaworzno” coalmine. This sort of coal shows great porosity, and great content of oxygen and moisture. The least amount of ethane is sorbed by hard coal from “Sośnica” coalmine. This sort of coal possesses relatively a great deal of ash contents. Together with the process of coal disintegration, the amount of sorbed ethane increases for all tested coal samples. Between tested coals there are three medium carbonized samples collected from “Pniówek”, “Chwałowice” “Zofiówka” coalmines which are characterized by small surface values counted according to model BET from nitrogen sorption isotherms determined at the temperature of 77.5 K. The samples of these three coals prove the highest, from between tested coals, increase of ethane sorption occurring together with their disintegration. These samples disintegrated to 0,063-0,075 mm grain class sorb ethane in the amount corresponding with the sorption quantity of low carbonized coal from “Jaworzno” coalmine in 0.5-0.7 mm grain class. It should be marked that the low carbonized samples collected from “Jaworzno” and Wesoła” coalmines possess large specific surface and great porosity and belong to coal group of “loose” spatial structure. Regarding profusion of sorbed ethane on disintegrated medium carbonized samples from “Pniówek”, “Zofiówka”, “Chwałowice” coalmines it can be supposed that in the process of coal disintegration, breaking their “compact’ structure occurs. Loosened structure of medium carbonized coals results in increasing accessibility of ethane particles to sorption centres both electron donors and electron acceptors which are present on hard coal surface. The surface sorption centre increase may result in formation a compact layer of ethane particles on coal surface. In the formed layer, not only the strengths of vertical binding of ethane particles with the coal surface appear but also the impact of horizontal strengths appears which forms a compact layer of sorbed ethane particles. The surface layer of ethane particles may lead to explosion.

IMPACT OF GOVERNMENT DEBT ON FINANCIAL SECURITY OF UKRAINE

2017 ◽  
Author(s):  
Olena Pikaliuk ◽  
◽  
Dmitry Kovalenko ◽  
Keyword(s):  
Economic Development ◽  
Public Debt ◽  
Positive Impact ◽  
The State ◽  
Financial Security ◽  
State Budget ◽  
The Public ◽  
Debt Security ◽  
The Stability ◽  
The Impact

One of the main criteria for economic development is the size of the public debt and its dynamics. The article considers the impact of public debt on the financial security of Ukraine. The views of scientists on the essence of public debt and financial security of the state are substantiated. An analysis of the dynamics and structure of public debt of Ukraine for 2014-2019. It is proved that one of the main criteria for economic development is the size of public debt and its dynamics. State budget deficit, attracting and using loans to cover it have led to the formation and significant growth of public debt in Ukraine. The volume of public debt indicates an increase in the debt security of the state, which is a component of financial security. Therefore, the issue of the impact of public debt on the financial security of Ukraine is becoming increasingly relevant. The constant growth and large amounts of debt make it necessary to study it, which will have a positive impact on economic processes that will ensure the stability of the financial system and enhance its security.

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