scholarly journals Structural Feature and Evolution Mechanism of Arch Structure for Thick Unconsolidated Layer

2021 ◽  
Author(s):  
Yingming Yang ◽  
Hengzhong Zhu ◽  
Quansheng Li ◽  
Kai Zhang ◽  
Yongqiang Zhao
Keyword(s):  
Mining Area ◽  
Theoretical Formula ◽  
Evolution Mechanism ◽  
Ground Fissures ◽  
Influence Mechanism ◽  
Geological Conditions ◽  
Arch Structure ◽  
The Relationship ◽  
Bearing Structure ◽  
Overlying Strata

Abstract Traditionally, the study on the bearing structure of overlying strata mainly focuses on bedrock with the effect of the overlying unconsolidated layer. It simply considered as uniformly loading on the top interface of the bedrock, and ignores the bearing structure for unconsolidated layer. Combined with the geological conditions of shallow burial thick unconsolidated layer in Shendong mining area,the mechanical model of the arch structure for the unconsolidated layers was established. The relationship between the arch height and span was analyzed with theoretical formula and the dynamic evolution mechanism of arch structure was studied with numerical simulation. Besides, formula of arch structure ultimate height was derived. The influence mechanism of arch structure on ground fissures was revealed and criterion was obtained, which was verified by field monitoring data. Furthermore, a classification method of arch structure in thick unconsolidated layers was proposed.

New Technology of Surface Subsidence Control and Environmental Protection Research in Coal Mining Region

2014 ◽  
Vol 675-677 ◽  
pp. 1385-1394
Author(s):  
Cheng Rong Jiang ◽  
Liu Yang ◽  
Hao Xie ◽  
Hua Yi Huang ◽  
De Ke Sun
Keyword(s):  
Coal Mining ◽  
New Technology ◽  
Mining Area ◽  
Industrial Test ◽  
Surface Subsidence ◽  
High Concentration ◽  
Geological Conditions ◽  
Surface Subsidence Control ◽  
Fissure Water ◽  
Overlying Strata

In combination with the geological conditions of Tie'er mining area in Tangshan coal mining, this paper not only analyzes the evolution of overlying strata structure in stope and the development law of overlying strata separation, also proposes a new continuous grouting technology with large flow and high concentration slurry. The industrial test showed that, when the grout-mining ratio of the whole mining area is 25.3%, the reducing subsidence ratio is 51.5%, the effect of reducing the surface subsidence is good. According to the chemical analysis of water quality ingredients of slurry, the test result showed, heavy metals contents in fly-ash slurry water do not exceed the standard, which has no bad effect on the fissure water in the bedrock.

scholarly journals Study on Roadheader Cutting Load at Different Properties of Coal and Rock

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Xueyi Li ◽  
Binbing Huang ◽  
Guoying Ma ◽  
Qingliang Zeng
Keyword(s):  
Simulation Analysis ◽  
Cutting Process ◽  
Theoretical Formula ◽  
Accurate Calculation ◽  
Cutting Test ◽  
Cutting Head ◽  
Element Simulation ◽  
Geological Conditions ◽  
The Relationship ◽  
Selection Of

The mechanism of cutting process of roadheader with cutting head was researched, and the influences of properties of coal and rock on cutting load were deeply analyzed. Aimed at the defects of traditional calculation method of cutting load on fully expressing the complex cutting process of cutting head, the method of finite element simulation was proposed to simulate the dynamic cutting process. Aimed at the characteristics of coal and rock which affect the cutting load, several simulations with different firmness coefficient were taken repeatedly, and the relationship between three-axis force and firmness coefficient was derived. A comparative analysis of cutting pick load between simulation results and theoretical formula was carried out, and a consistency was achieved. Then cutting process with a total cutting head was carried out on this basis. The results show that the simulation analysis not only provides a reliable guarantee for the accurate calculation of the cutting head load and improves the efficiency of the cutting head cutting test but also offers a basis for selection of cutting head with different geological conditions of coal or rock.

Research on the Overlying Strata in Full-Mechanized Coal Mining of Datong Jurassic Coal Multi-Layer Goaf

2012 ◽  
Vol 616-618 ◽  
pp. 402-405 ◽  
Author(s):  
Hong Chun Xia ◽  
Guo Sheng Gao ◽  
Bin Yu
Keyword(s):  
Coal Seam ◽  
Coal Mining ◽  
Coal Pillar ◽  
Mining Area ◽  
Mechanics Model ◽  
Roof Structure ◽  
Geological Conditions ◽  
Seam Mining ◽  
The Impact ◽  
Overlying Strata

According to the specific geological conditions in themulti-layer worked-out areas of Yongding coal seam, by the methods of integration of theoretic analysis, numerical value calculation and so on, we studied movement law of Overlaying Strata and influence of coal pillar in Coal seam mining, obtained the basic law of the overlying strata movement in multiplayer, provides a theoretical basis for the safe and efficient exploitation of the success of multiplayer. Many mining area in China is mining of closed distance coal seam group, By the impact of coal seam in the overlying, face and the tunnel roof structure will be different injury in sub-coal seam mining, Roof structure has changed greatly, even damage and easily take the roof leakage, When the the goaf communication with the overlying coal seams, caused by the induced secondary disasters such as face air leakage, Therefore, exploitation of the law of motion of the overlying strata in the multiplayer is a pressing problem. Exploitation multiplayer seam few theoretical and technical foundation at home and abroad, affecting the validity of the mining, rationality. although a lot of research on theory and technology of coal mining over the years[1~5], But it was not able to an overall comprehensive analysis of upper goaf adjacent goaf and overlying the coal pillar and present mining face, create a dynamic structural mechanics model, which is likely to cause the occurrence of disasters.

scholarly journals Evolution of Interior and Exterior Bearing Structures of the Deep-Soft-Rock Roadway: From Theory to Field Test in the Pingdingshan Mining Area

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4357
Author(s):  
Qingxian Huang ◽  
Xufeng Wang ◽  
Xuyang Chen ◽  
Dongdong Qin ◽  
Zechao Chang
Keyword(s):  
Field Test ◽  
Soft Rock ◽  
Field Measurements ◽  
Mining Area ◽  
Surrounding Rock ◽  
Roadway Stability ◽  
Geological Conditions ◽  
Soft Rock Roadway ◽  
Bearing Structure ◽  
Rock Roadway

Pingdingshan mining area is one of the typical deep mining areas in China, and most of the mines in this area are troubled by the difficulties of the deep-soft-rock roadway support. Based on the concept of synergistic interactions of the interior and exterior bearing structure of the surrounding rock and, considering the specific geological conditions of the research site, we establish the mechanical model of the interior and exterior bearing structure of the roadway. Based on numerical simulation, we reveal the influence of main factors, such as support strength and mechanical characteristics, of surrounding rock on the distribution and evolution of the interior and exterior bearing structure. We found that increasing the support strength and mechanical parameters of surrounding rock can make the exterior bearing structure close to the roadway enhance the bearing characteristics of the interior and exterior bearing structure and improve the roadway stability. The distribution characteristics of the interior and exterior bearing structure of the roadway under six different support strengths and six different grouting parameters were systematically investigated by field measurements. According to the field test results, an effective strategy for controlling the deep-soft-rock roadway is proposed, which provides a good reference for surrounding rock control of the deep-soft-rock roadway in the Pingdingshan mining area and mines with similar mining conditions.

Numerical Analysis on Top Coal Caving of 2# Coal Seam in First Mine of Chagannaoer

2012 ◽  
Vol 594-597 ◽  
pp. 1338-1342
Author(s):  
Qing Hai Li ◽  
Ren Shu Yang ◽  
Wei Ping Shi
Keyword(s):  
Numerical Analysis ◽  
Plastic Zone ◽  
Coal Seam ◽  
Comprehensive Evaluation ◽  
Fuzzy Comprehensive Evaluation ◽  
Mining Technology ◽  
Geological Conditions ◽  
Numerical Software ◽  
Evolution Laws ◽  
Overlying Strata

In first mine of Chagannaoer, 2# coal seam, the mainly mined out layer, was 22.00m thickness in average. In order to meet the requirements of production ability, the mine was planned to apply mining technology of fully mechanized caving. Good or bad of top coal’s caving was an important prerequisite which decided the mining technology of top coal caving could be chosen or not. Due to lack of producing mines in this region and no experience to refer, we simulated the mining process of 2# coal seam using numerical software of FLAC3D, and gained evolution laws of stress and displacement of top coal and overlying strata and expansion laws of plastic zone. Through analysis, we got that the top coal damaged seriously and the top coal could be caved smoothly. Relying on the geological conditions of site, we verified the simulated results with method of fuzzy comprehensive evaluation. Combined with the research results, we decided that 2# coal seam’s caving was better and was convenient for top coal caving, so it was suitable for caving mining in 2# coal seam in first mine of Chagannaoer.

scholarly journals The Mineral Chemistry of Chlorites and Its Relationship with Uranium Mineralization from Huangsha Uranium Mining Area in the Middle Nanling Range, SE China

Minerals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 199 ◽  
Author(s):  
Dehai Wu ◽  
Jiayong Pan ◽  
Fei Xia ◽  
Guangwen Huang ◽  
Jing Lai
Keyword(s):  
Mining Area ◽  
Uranium Mining ◽  
Uranium Mineralization ◽  
Formation Mechanisms ◽  
Chemical Compositions ◽  
Type I ◽  
Low Oxygen ◽  
Nanling Range ◽  
The Relationship ◽  
Uranium Mining Area

The Huangsha uranium mining area is located in the Qingzhangshan uranium-bearing complex granite of the Middle Nanling Range, Southeast China. This uranium mining area contains three uranium deposits (Liangsanzhai, Egongtang, and Shangjiao) and multiple uranium occurrences, showing favorable mineralization conditions and prospecting potential for uranium mineral resources. Chloritization is one of the most important alteration types and prospecting indicators in this mining area. This study aims to unravel the formation environment of chlorites and the relationship between chloritization and uranium mineralization, based on detailed field work and petrographic studies of the wallrock and ore samples from the Huangsha uranium mining area. An electron probe microanalyzer (EPMA) was used in this study to analyze the paragenetic association, morphology, and chemical compositions of chlorite, to classify chemical types and to calculate formation temperatures and n(Al)/n(Al + Mg + Fe) values of chlorite. The formation mechanism and the relationship with uranium mineralization of the uranium mining area are presented. Some conclusions from this study are: (1) There are five types of chlorites, including the chlorite formed by the alteration of biotite (type-I), by the metasomatism of feldspar with Fe–Mg hydrothermal fluids (type-II), chlorite vein/veinlet filling in fissures (type-III), chlorite closely associated with uranium minerals (type-IV), and chlorite transformed from clay minerals by adsorbing Mg- and Fe-components (type-V). (2) The chlorite in the Huangsha uranium mining area belongs to iron-rich chlorite and is mainly composed of chamosite, partly clinochlore, which are the products of multiple stages of hydrothermal action. The original rocks are derived from argillite, and their formation temperatures vary from 195.7 °C to 283.0 °C, with an average of 233.2 °C, suggesting they formed under a medium to low temperature conditions. (3) The chlorites were formed under reducing conditions with low oxygen fugacity and relatively high sulfur fugacity through two formation mechanisms: dissolution–precipitation and dissolution–migration–precipitation; (4) The chloritization provided the required environment for uranium mineralization, and promoted the activation, migration, and deposition of uranium.

Equilibrium Temperature Calculation of the Sulfur Isotope in Dongzhongla Pb-Zn Deposit in Tibet

2015 ◽  
Vol 1092-1093 ◽  
pp. 1394-1397
Author(s):  
Guang Chun Fei ◽  
Yi Fan Yu ◽  
Ke Qiang Hua
Keyword(s):  
Sulfur Isotope ◽  
Equilibrium Temperature ◽  
Mining Area ◽  
Isotopic Equilibrium ◽  
The North ◽  
Geological Conditions ◽  
Typical Type ◽  
Lead Zinc ◽  
Block Based ◽  
Exploration Area

The Dongzhongla Pb-Zn deposit, a newly-discovered medium-sized deposit, is located in the north margin of the eastern Gangdese, central Lhasa block. Based on the analysis of the ore-forming geological conditions in this deposit, sulfur isotope of this deposit were analyzed, and S isotopic equilibrium temperature of mineral pairs (sphalerite and galena) were calculated. This study has shown that the sulfur isotopic equilibrium temperature of sphalerite and galena in Dongzhongla Pb-Zn deposit ranged from 185℃ to 296℃. It indicated that the equilibrium temperature decreased gradually from the skarn stage to sulfide stage. The equilibrium temperature can be used as the reference of metallogenic temperature for Dongzhongla Pb-Zn deposit. DongzhongLa deposit is the typical type of skarn Lead-zinc deposit. East of the Dongzhongla mining area is the priority exploration area.

scholarly journals BER Performance Analysis of Non-Coherent Q-Ary Pulse Position Modulation Receivers on AWGN Channel

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6102
Author(s):  
Xianhua Shi ◽  
Yimao Sun ◽  
Jie Tian ◽  
Maolin Chen ◽  
Youjiang Liu ◽  
...  
Keyword(s):  
Gaussian Noise ◽  
Additive White Gaussian Noise ◽  
Theoretical Formula ◽  
Pulse Position Modulation ◽  
Error Performance ◽  
Optimal Receiver ◽  
Awgn Channel ◽  
Simulation Results ◽  
The Relationship ◽  
Better Than

This paper introduces the structure of a Q-ary pulse position modulation (PPM) signal and presents a noncoherent suboptimal receiver and a noncoherent optimal receiver. Aiming at addressing the lack of an accurate theoretical formula of the bit error rate (BER) of a Q-ary PPM receiver in the additive white Gaussian noise (AWGN) channel in the existing literature, the theoretical formulas of the BER of a noncoherent suboptimal receiver and noncoherent optimal receiver are derived, respectively. The simulation results verify the correctness of the theoretical formulas. The theoretical formulas can be applied to a Q-ary PPM system including binary PPM. In addition, the analysis shows that the larger the Q, the better the error performance of the receiver and that the error performance of the optimal receiver is about 2 dB better than that of the suboptimal receiver. The relationship between the threshold coefficient of the suboptimal receiver and the error performance is also given.

scholarly journals PENATAAN HUBUNGAN HUKUM DALAM PENGUASAAN, PEMILIKAN, PENGGUNAAN, DAN PEMANFAATAN SUMBER DAYA AGRARIA (Studi Awal terhadap Konsep Hak Atas Tanah dan Ijin Usaha Pertambangan)

2016 ◽  
Vol 2 (1) ◽  
pp. 1
Author(s):  
Oloan Sitorus
Keyword(s):  
Land Tenure ◽  
Land Use Planning ◽  
Mining Area ◽  
New Order ◽  
Land Law ◽  
Land Utilization ◽  
Legal Relation ◽  
Set Up ◽  
The Right ◽  
The Relationship

Abstract: The legal relations of land tenure, ownership, usage and utilization of agrarian resources still require furtherrestructurization. The economic development during the New Order era abandoned the necessity of the legal differences of landtenure and land ownership, with the legal relations of the collection and utilization of agrarian resources excluding land. Consequently,there are misleading in interpreting the right and permission as a form of legal relationship. These misleading should berectified in the land law draft which will be drafted. The future land law should be able to clearly regulate the legal relations of landtenure, and should be consistently built since the early tenure in the form of occupation, possession, and ownership by the Ministryof Agrarian and Land Use Planning/NLA. Land tenure relationship is mentioned by the concept of land right. Furthermore, it shouldbe confirmed in the Land Law Draft that the relationship between collection and utilization of natural resources are confirmed aspermit, and should not be considered as the basic of land utilization as earth surface. Reclamation set up by the concession holdersfor mining area recovery should not be considered as an “entry point” to legalize land rights.Keywords: legal relation, right, licenseIntisari: Hubungan hukum penguasaan dan pemilikan serta penggunaan dan pemanfaatan Sumberdaya Agraria masih memerlukanpenataan. Perkembangan ekonomi selama era Orde Baru mengabaikan pentingnya pembedaan hubungan hukum tenurial penguasaandan pemilikan tanah dengan hubungan hukum pengambilan dan pemanfaatan sumberdaya agraria selain tanah. Akibatnya, terjadikesesatan berfikir dalam mamaknai hak dan ijin sebagai bentuk hubungan hukum. Kesesatan berfikir ini harus diakhiri di dalam RUUPertanahan yang akan disusun. RUU Pertanahan itu harus jelas mengatur bahwa hubungan hukum tenurial dengan tanah haruskonsisten dibangun sejak penguasaan awal dalam bentuk okupasi (occupation), penguasaan dan pemunyaaan (possession), danpemilikan (ownership) oleh Kementerian ATR/BPN. Hubungan tenurial dengan tanah disebut dengan konsep hak atas tanah.Selanjutnya, perlu dikonfirmasi dalam RUU Pertanahan tersebut bahwa hubungan pengambilan dan pemanfaatan kekayaan alamdikonfirmasi sebagai ijin, yang tidak dapat dijadikan sebagai dasar untuk menggunakan tanah sebagai permukaan bumi. Reklamasiyang dilakukan pemegang ijin untuk memulihkan areal tambang, tidak dapat dijadikan sebagai “pintu masuk” bagi terjadinya hak atastanah.Kata kunci: hubungan hukum, hak atas tanah, ijin

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