scholarly journals Zoning Control Technology of Gob-Side Roadway Driving with Small Coal Pillar Facing Mining in a Special Isolated Island Working Face: A Case Study

2021 ◽  
Vol 11 (22) ◽  
pp. 10744
Author(s):  
Changliang Han ◽  
Houqiang Yang ◽  
Nong Zhang ◽  
Rijian Deng ◽  
Yuxin Guo
Keyword(s):  
Control Method ◽  
Coal Pillar ◽  
Control Technology ◽  
Stability Zone ◽  
Pressure Relief ◽  
Collaborative Control ◽  
Working Face ◽  
Underground Coal Mines ◽  
Engineering Practices

The gob-side roadway in an isolated island working face is a typical representative of a strong mining roadway, which seriously restricts the efficient and safe production of underground coal mines. With the engineering background of the main transportation roadway 1513 (MTR 1513) of the Xinyi Coal Mine, this paper introduces the engineering case of gob-side roadway driving with small coal-pillar facing mining in an isolated island working face under the alternate mining of wide and narrow working faces. Through comprehensive research methods, we studied zoning disturbance deformation characteristics and stress evolution law of gob-side roadway driving under face mining. Based on the characteristics of zoning disturbance, MTR 1513 is divided into three zones, which are the heading face mining zone, the mining influenced zone, and the mining stability zone. A collaborative control technology using pressure relief and anchoring is proposed, and the differentiated control method is formed for the three zones. For the heading face mining zone, the control method of anchoring first and then pressure relief is adopted; for the mining influenced zone, the control idea of synchronous coordination of pressure relief and anchorage is adopted; for the mining stability zone, the control method of anchoring without pressure relief is adopted. Engineering practices show that the disturbance influence distance of working face 1511 on MTR 1513 changes from 110 m advanced to 175 m delay. At this time, the surrounding rock deformation is effectively controlled, which verified the rationality of the division and the feasibility of three zoning control technology. The research results can provide reference for gob-side roadway driving with small coal pillar facing mining in a special isolated island working face.

scholarly journals Analysis on Rock Burst Risks and Prevention of a 54 m-Wide Coal Pillar for Roadway Protection in a Fully Mechanized Top-Coal Caving Face

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Zhihua Li ◽  
Ke Yang ◽  
Jianshuai Ji ◽  
Biao Jiao ◽  
Xiaobing Tian
Keyword(s):  
Coal Seam ◽  
Rock Burst ◽  
Influencing Factors ◽  
Abutment Pressure ◽  
Large Diameter ◽  
Coal Pillar ◽  
Distribution Characteristics ◽  
Pressure Relief ◽  
Working Face ◽  
Coal Pillars

A case study based on the 401103 fully mechanized caving face in the Hujiahe Coal Mine was carried out in this research to analyze the rock burst risks in a 54 m-wide coal pillar for roadway protection. Influencing factors of rock burst risks on the working face were analyzed. Stress distribution characteristics on the working face of the wide coal pillar for roadway protection were discussed using FLAC3D numerical simulation software. Spatial distribution characteristics of historical impact events on the working face were also investigated using the microseismic monitoring method. Results show that mining depth, geological structure, outburst proneness of coal strata, roof strata structure, adjacent mining area, and mining influence of the current working face are the main influencing factors of rock burst on the working face. Owing to the collaborative effects of front abutment pressure of the working face and lateral abutment pressure in the goaf, the coal pillar is in the ultimate equilibrium state and microseismic events mainly concentrate in places surrounding the coal pillars. Hence, wide coal pillars become the regions with rock burst risks on the working face. The working face adopts some local prevention technologies, such as pressure relief through presplitting blasting in roof, pressure relief through large-diameter pores in coal seam, coal seam water injection, pressure relief through large-diameter pores at bottom corners, and pressure relief through blasting at bottom corners. Moreover, some regional prevention technologies were proposed for narrow coal pillar for roadway protection, including gob-side entry, layer mining, and fully mechanized top-coal caving face with premining top layer.

Study on Rational Width of Entry Protection Coal-Pillar in Large Mining Height Working Face

2011 ◽  
Vol 413 ◽  
pp. 404-409
Author(s):  
Xu Feng Wang ◽  
Dong Sheng Zhang ◽  
Ting Feng Cui ◽  
Jin Liang Wang ◽  
Wei Zhang
Keyword(s):  
Numerical Simulation ◽  
Theoretical Calculation ◽  
Coal Pillar ◽  
Engineering Practice ◽  
Pillar Width ◽  
Pillar Design ◽  
Working Face ◽  
Large Mining Height ◽  
Mining Height

This paper demonstrates the attempt to identify a reasonable chain pillar width in the condition of large mining height, along with a case study at the gateway of No.1103 panel with large mining height in Suancigou Mine. Theoretical calculation and numerical simulation were employed as the main approaches during the research to figure out the rational width of entry protection coal-pillar, which was then proved to be capable for engineering practice. The results that derived from our research can offer technical support for spot production, and serve as references for future investigation upon chain pillar design under large mining height.

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.

scholarly journals Towards Regulatory-Compliant MLOps: Orazivio’s Journey from a Machine Learning Experiment to a Deployed Certified Medical Product

2021 ◽  
Vol 2 (5) ◽  
Author(s):  
Tuomas Granlund ◽  
Vlad Stirbu ◽  
Tommi Mikkonen
Keyword(s):  
Machine Learning ◽  
Joint Replacement ◽  
Medical Product ◽  
Medical Software ◽  
Continuous Delivery ◽  
Development Approach ◽  
Responding To Change ◽  
Agile Software ◽  
Engineering Practices

AbstractAgile software development embraces change and manifests working software over comprehensive documentation and responding to change over following a plan. The ability to continuously release software has enabled a development approach where experimental features are put to use, and, if they stand the test of real use, they remain in production. Examples of such features include machine learning (ML) models, which are usually pre-trained, but can still evolve in production. However, many domains require more plan-driven approach to avoid hazard to environment and humans, and to mitigate risks in the process. In this paper, we start by presenting continuous software engineering practices in a regulated context, and then apply the results to the emerging practice of MLOps, or continuous delivery of ML features. Furthermore, as a practical contribution, we present a case study regarding Oravizio, first CE-certified medical software for assessing the risks of joint replacement surgeries. Towards the end of the paper, we also reflect the Oravizio experiences to MLOps in regulatory context.

Geotextile encased columns (GEC) used as pressure-relief system. Instrumented bridge abutment case study on soft soil

2017 ◽  
Vol 45 (3) ◽  
pp. 227-236 ◽  
Author(s):  
F. Schnaid ◽  
D. Winter ◽  
A.E.F. Silva ◽  
D. Alexiew ◽  
V. Küster
Keyword(s):  
Soft Soil ◽  
Pressure Relief ◽  
Bridge Abutment ◽  
Relief System

Collaborative idea exchange and material tinkering influence families’ creative engineering practices and products during engineering programs in informal learning environments

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Soo Hyeon Kim ◽  
Heather Toomey Zimmerman
Keyword(s):  
Design Research ◽  
Naturalistic Inquiry ◽  
Content Type ◽  
Engineering Programs ◽  
Solution Generation ◽  
Quantitative Analyses ◽  
Feasible Solutions ◽  
Engineering Practices ◽  
Parent Child

Purpose This paper aims to investigate how families’ sociomaterial experiences in engineering programs held in libraries and a museum influence their creative engineering practices and the creativity expressed in their products derived from their inquiry-driven engineering activities. Design/methodology/approach This research project takes a naturalistic inquiry using qualitative and quantitative analyses based on video records from activities of 31 parent–child pairs and on creativity assessment of products that used littleBits as prototyping tools. Findings Families engaged in two sociomaterial experiences related to engineering – collaborative idea exchange and ongoing generative tinkering with materials – which supported the emergence of novel ideas and feasible solutions during the informal engineering programs. Families in the high novelty score group experienced multiple instances of collaborative idea exchange and ongoing generative tinkering with materials, co-constructed through parent-child collaboration, that were expansive toward further idea and solution generation. Families in the low novelty score group experienced brief collaborative idea exchange and material tinkering with specific idea suggestions and high involvement from the parent. An in-depth case study of one family further illustrated that equal engagement by the parent and child as they tinkered with the technology supported families’ creative engineering practices. Originality/value This analysis adds to the information sciences and learning sciences literatures with an account that integrates methodologies from sociocultural and engineering design research to understand the relationship between families’ engagement in creative engineering practices and their products. Implications for practitioners include suggestions for designing spaces to support families’ collaborative idea exchange and ongoing generative tinkering to facilitate the development of creative engineering practices during short-term engineering programs.

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