BOREHOLE‐RADAR EXPLORATION IN A COAL SEAM

Geophysics ◽  
1977 ◽  
Vol 42 (6) ◽  
pp. 1254-1257 ◽  
Author(s):  
John C. Cook
Keyword(s):  
Coal Seam ◽  
Practical Importance ◽  
Low Resolution ◽  
Coal Seams ◽  
Australian Society ◽  
Great Practical Importance ◽  
The Third ◽  
Research Organizations ◽  
Borehole Radar ◽  
Experimental Use

The experimental use of “geologic radar” to explore through coal from mined passages underground has already been reported elsewhere (Cook, 1973, 1974). Low‐resolution borehole radar work in salt, a much more favorable medium, has also been reported (Holzer et al., 1972). The purpose of this paper is to report the first known results of borehole radar tests in coal. The exploration of coal seams via boreholes from the surface is potentially a technique of great practical importance. The borehole experiment was performed in conjunction with a month‐long program of radar tests in Australian collieries and quarries performed under the sponsorship of the third ICOGEO and supported by several Australian mining and research organizations. A report on that program is expected to appear in the Bulletin of the Australian Society of Exploration Geophysicists some time during 1977.

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.

scholarly journals Comprehensive technical support for safe mining in ultra-close coal seams: A case study

2021 ◽  
pp. 014459872110093
Author(s):  
Wei Zhang ◽  
Jiawei Guo ◽  
Kaidi Xie ◽  
Jinming Wang ◽  
Liang Chen ◽  
...  
Keyword(s):  
Coal Seam ◽  
Technical Support ◽  
Surrounding Rock ◽  
Coal Seams ◽  
Deformation Control ◽  
Hard Roof ◽  
Working Face ◽  
Close Coal Seams ◽  
Safe Mining

In order to mine the coal seam under super-thick hard roof, improve the utilization rate of resources and prolong the remaining service life of the mine, a case study of the Gaozhuang Coal Mine in the Zaozhuang Mining Area has been performed in this paper. Based on the specific mining geological conditions of ultra-close coal seams (#3up and #3low coal seams), their joint systematic analysis has been performed, with the focus made in the following three aspects: (i) prevention of rock burst under super-thick hard roof, (ii) deformation control of surrounding rock of roadways in the lower coal seam, and (iii) fire prevention in the goaf of working face. Given the strong bursting tendency observed in upper coal seam and lower coal seam, the technology of preventing rock burst under super-thick hard roof was proposed, which involved setting of narrow section coal pillars to protect roadways and interleaving layout of working faces. The specific supporting scheme of surrounding rock of roadways in the #3low1101 working face was determined, and the grouting reinforcement method of local fractured zones through Marithan was further proposed, to ensure the deformation control of surrounding rock of roadways in lower coal seams. The proposed fire prevention technology envisaged goaf grouting and spraying to plug leaks, which reduced the hazard of spontaneous combustion of residual coals in mined ultra-close coal seams. The technical and economic improvements with a direct economic benefit of 5.55 million yuan were achieved by the application of the proposed comprehensive technical support. The research results obtained provide a theoretical guidance and technical support of safe mining strategies of close coal seams in other mining areas.

Speech influence in advertising texts

2020 ◽  
Vol 45 (4) ◽  
pp. 106-114
Author(s):  
Y. Kim ◽  
◽  
А. Yermekbayeva ◽  
Keyword(s):  
Practical Importance ◽  
Russian Language ◽  
Main Body ◽  
Structural Elements ◽  
School Teachers ◽  
High Quality ◽  
Great Practical Importance ◽  
Advertising Message ◽  
Potential Consumer ◽  
The Russian Language

This work is devoted to the speech impact of advertising texts, in other words, the language of advertising, the purpose of which is to attract the attention of a potential consumer by making the message as memorable and unusual as possible, lively and catchy, colorful and attractive to a potential listener / buyer. The significance of the work lies in the fact that the author, in the process of analyzing the basic structural elements of the advertising message (slogan and main body), determines the main speech techniques for the influence of advertising texts: expressive means, including metaphors, epithets metonymy, speech turns, paths, various grammatical forms and other forms of influence: nominative, one-part, verb sentences, comparative and superlative adjectives, rhymes, imperative verbs, adverbs, lexical repetition. On specific examples of advertising slogans, evidence is given that the above speech means contribute to increased demand for the advertised product or service. During the study, the author confirms the hypothesis put forward at the beginning of the study: if you skillfully use speech exposure, i.e. to choose words whose harmonious combination lays in the subconscious of a person the information transmitted to him by the manufacturer through high-quality advertising, then such an advertising text can become the key to the success of trade. The work is of great practical importance: the material presented in it can be used by students to improve the culture of speech, improve stylistically differentiated speech, as well as school teachers as methodological material in the Russian language when studying the section «Vocabulary», «Stylistics».

Blood calcium for eczema

1935 ◽  
Vol 31 (6) ◽  
pp. 726-734
Author(s):  
N. N. Yasnitsky ◽  
Ts. D. Elina
Keyword(s):  
Practical Importance ◽  
Experimental Studies ◽  
Controversial Issue ◽  
Scientific Interest ◽  
Blood Calcium ◽  
Great Practical Importance

One of the urgent problems of modern dermatology, which are of deep scientific interest and are of extremely great practical importance, is the complex and controversial issue of the etiology of eczema. However, despite the colossal literature, despite a number of detailed experimental studies, the main and deep contradictions of representatives of the main dermatological schools on the nature of eczema remain unresolved.

Practical value of skin temperature measurement

1934 ◽  
Vol 30 (10) ◽  
pp. 1049-1050
Author(s):  
I. Johs
Keyword(s):  
Temperature Measurement ◽  
Skin Temperature ◽  
Practical Importance ◽  
Great Practical Importance ◽  
Artery Embolism

Skin temperature depends mainly on the amount of incoming blood and is of great practical importance. In limb artery embolism the skin temperature reveals a large difference on the healthy and diseased limb. In doubtful cases this symptom allows a diagnosis to be made after 1-2 hours and a timely operation to be undertaken.

scholarly journals Identifying Correlation of Coal Seams in the Tien Hai Area, Northern Vietnam by Using Multivariate Statistic Methods

2021 ◽  
Vol 1 (2) ◽  
Author(s):  
The Hung KHUONG ◽  
Phuong NGUYEN ◽  
Thi Cuc NGUYEN ◽  
Nhu Sang PHAM ◽  
Danh Tuyen NGUYEN
Keyword(s):  
Trace Elements ◽  
Rare Earth ◽  
Coal Seam ◽  
Rare Earth Elements ◽  
Major And Trace Elements ◽  
Coal Seams ◽  
Multivariate Statistic ◽  
Northern Vietnam ◽  
Coal Deposits ◽  
Indicator Elements

In northern Vietnam, the Tien Hai area is considered a high potential area of coal deposits. Twohundred fifty-six geochemical coal samples of 13 cores in the Tien Hai area investigate coal seams andcoal deposits to identify the correlation of coal seams. According to the statistical method and clusteranalysis of geochemical samples, the results indicate that the Mg, V, As, Ca, Zn, Cr, Co, K, Na, Sr, Fe,Ge, Re, U, Mo, Th, and Ga elements are good indicator elements of the major and trace elements in coal.Most of them comply with the normal or lognormal distribution rules. Besides, the Yb, Sc, Ho, Er, Tm,Lu, Y, Tb, Pr, Dy, and Sm elements are also good indicator elements for rare earth elements in the region.Therefore, the selected elements are used to identify the correlation of the coal seams in the Tien Hai area.Based on the similarity degree between studied objects, the results of grouping boreholes in coal seamsshow that the correlation of coal seam TV2-11 is suitable and acceptable, the coal seams TV3-6a, TV3-6b, and TV3-6c can be grouped into the coal seam TV3-6. These results present that the models can helpstudy geochemical coal samples and identify the correlation of the coal seams in the Tien Hai area.Additionally, the statistical analysis shows a remarkable degree to determine the correlation of the coalseams. Geochemical coal data can help to evaluate the indicator elements of the major, trace elements,and rare earth elements in coal seams and coal rashing of adjoining and pillar rocks in the Tien Hai area,northern Vietnam.

scholarly journals Attitudes Towards Computer In An Information-Intense Environment: A Field Study Of The Insurance Industry

2011 ◽  
Vol 7 (4) ◽  
pp. 123 ◽  
Author(s):  
David L. Turnipseed ◽  
O. Maxie Burns ◽  
Frank J. Hodges
Keyword(s):  
Field Study ◽  
Insurance Industry ◽  
Practical Importance ◽  
Popular Literature ◽  
Automated Systems ◽  
Great Practical Importance ◽  
Chess Game ◽  
Computer Interaction

The topic of human attitudes about computers has been dealt with extensively in both the academic and popular literature, but it remains an issue of importance. The continued relevance was well illustrated by the Soviet chess grandmaster, Karpov, who recently remarked that he was not afraid to lose a chess game to a computer, but that people who worked with such computers could lose their soul to the machines (Hooper, 1990). The beliefs which people hold toward computers will affect their computer interaction and their willingness to adapt to automated systems: therefore the issue is of great practical importance. This paper reports on a replication of an early IBM study with the intent of assessing contemporary attitudes towards computers and the changes in attitudes over the last 25 years.

scholarly journals Surrounding Rock Movement of Steeply Dipping Coal Seam Using Backfill Mining

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Wenyu Lv ◽  
Kai Guo ◽  
Jianhao Yu ◽  
Xufeng Du ◽  
Kun Feng
Keyword(s):  
Numerical Simulation ◽  
Coal Seam ◽  
Surrounding Rock ◽  
Maximum Deflection ◽  
Coal Seams ◽  
Physical Similarity ◽  
Working Face ◽  
Rock Structure ◽  
Backfill Mining ◽  
The Stability

The movement of the overlying strata in steeply dipping coal seams is complex, and the deformation of roof rock beam is obvious. In general, the backfill mining method can improve the stability of the surrounding rock effectively. In this study, the 645 working face of the tested mine is used as a prototype to establish the mechanical model of the inclined roof beam using the sloping flexible shield support backfilling method in a steeply dipping coal seam, and the deflection equation is derived to obtain the roof damage structure and the maximum deflection position of the roof beam. Finally, numerical simulation and physical similarity simulation experiments are carried out to study the stability of the surrounding rock structure under backfilling mining in steeply dipping coal seams. The results show the following: (1) With the support of the gangue filling body, the inclined roof beam has smaller roof subsidence, and the maximum deflection position moves to the upper part of working face. (2) With the increase of the stope height, the stress and displacement field of the surrounding rock using the backfilling method show an asymmetrical distribution, the movement, deformation, and failure increase slowly, and the increase of the strain is relatively stable. Compared with the caving method, the range and degree of the surrounding rock disturbed by the mining stress are lower. The results of numerical simulation and physical similarity simulation experiment are generally consistent with the theoretically derived results. Overall, this study can provide theoretical basis for the safe and efficient production of steeply dipping coal seams.

scholarly journals NEW ASPECTS OF THE ENZYMATIC BREAKDOWN OF CHITIN: A REVIEW

2021 ◽  
Vol 26 ◽  
pp. 5-10
Author(s):  
Urszula Jankiewicz ◽  
◽  
Arletta Kochańska-Jeziorska ◽  
Agnieszka Gałązka
Keyword(s):  
Crystalline Structure ◽  
Enzymatic Degradation ◽  
Soluble Sugars ◽  
Practical Importance ◽  
Oxidative Cleavage ◽  
Lytic Polysaccharide Monooxygenase ◽  
Great Practical Importance ◽  
Polysaccharide Monooxygenase

This review focuses on the enzymatic breakdown of chitin, taking into account the latest scientific reports on the activity of lytic polysaccharide monooxygenase (LPMO). Chitin is a natural, abundant polysaccharide of great practical importance in the environment. However, the insolubility in water and the tightly packed crystalline structure of chitin pose a serious obstacle to enzymatic degradation. This substrate can be converted into soluble sugars by the action of glycosidic hydrolases (GH), also known as chitinases. LPMO could prove to be helpful in enzymatic processes that increase the rate of chitin depolymerisation by improving the availability of substrates for chitinases. The unique action of LPMO is based on the ability to catalyse the oxidative cleavage of glycosidic chains present in complex, resistant crystal networks of chitin, and this cleavage facilitates the subsequent action of glycolytic hydrolases.

Research on Nano-Emulsion Relieving Coal Seam Water Block Damage

2021 ◽  
Author(s):  
Wei Sun ◽  
LongHao Zhao ◽  
Qian Wang ◽  
Yanchi Liu ◽  
Weiping Zhu ◽  
...  
Keyword(s):  
Coal Seam ◽  
Coalbed Methane ◽  
Mixed Micelles ◽  
Polymer Adsorption ◽  
Coal Seams ◽  
Fracturing Fluid ◽  
Flow Experiment ◽  
Nano Emulsion ◽  
Water Block ◽  
Lock In

Abstract Hydraulic fracturing is the most effective reservoirstimulation techniques in the coalbed methane. However, the polymer in the fracturing fluid has a strong effect on the surface of the coal, causing the water lock damage as high as 70% to 90%. It is important to develop an efficient method for releasing coal seam water lock. In this paper, adsorption experiment, SEM, particle size experiment, core flow experiment, wettability and surface tension experiment are used to study the cause of coal seam water lock damage during fracturing and the effect of nano-emulsion on releasing water lock damage in coal seams. Experimental results show that after coal fracturing, the adsorption amount of polymer on the surface of coal is 14.81 mg/g. The large amount of hydrophilic polymer adsorption causes the pore radius of the coal to narrow. And the surface wettability changes from weak hydrophilic to strong hydrophilic, which increase the water lock damage. Compared with conventional slick water, fracturing fluid, the composite of nano-emulsion and fracturing fluid forms mixed micelles, which reduces the polymer adsorption capacity from 14.81 mg/g to 7.42 mg/g. After scanning by electron microscope, it is observed that the surface roughness of the rock sample is restored; The size of the nano-emulsion is about 10nm, and the very small volume can act deep in the pores of the coal seam; After using nano-emulsion, the gas/water interfacial tension is reduced by 45.1mN/m, and the wettability of coal is improved from hydrophilic to neutral, which reduces the capillary pressure in the pores of the coal and reduces the breakthrough pressure of coalbed methane by 11.1KPa; The water lock release rate is as high as 53.09%. The Nano-emulsion is an ideal choice to remove water lock damage.

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