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Impact of geo technical factors on strata behavior in longwall panels of Godavari Valley coal field-a case study

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International Journal of mining Science and Technology 2019年第2期29卷 335-341页

作者： Veera Reddy Boothukuri Ram Madhav Bhattacharjee Durga Charan Panigrahi Gautam Benerjee Singareni Collieries Company Limited (SCCL) Indian institute of Technology Indian School of Mines CSIR-central institute of mining and fuel research

Understanding the cantilevers formed by thick, massive beds in the near-seam overburden above longwall panels and the associated loads and strata fracturing effects developed during caving(main and periodic weightings) are key elements for the successful implementation of longwalls. Such caving mechanisms rely on the geotechnical conditions within the panel. In India, the majority of longwall downtime and/or roof failures were caused by a lack of knowledge on overburden caveability, in particular when the main and periodic weightings will impact the face and longwall support selection to effectively mitigate such weightings. Godavari Valley Coal Fields is no exception as longwall faces were adversely affected due to the presence of thick, massive beds in the near-seam overburden at both Godavarikhani(GDK) 7 and 9 Incline mines. In contrast, overburden weightings were negotiated successfully in GDK10 A and Adriyala Longwall Project(ALP) mines by detailed geotechnical studies, the use of adequate longwall support capacities, and effective operational practices. Thirteen longwall panels with varying face width, at different depths have been extracted under massive sandstone beds of 18 m to28 m thickness at GDK 10 A and ALP mines. This study elucidates that the main roof weighting interval decreases with an increase in face width and attains a constant value with further increases in face width under the same geo-mining conditions. In addition, this study also concludes that with increases in face width, the periodic roof weighting interval decreases and shield loads increase. Similarly with increasing panel width to depth ratio, the main and periodic roof weighting intervals decrease but shield loads again increase. Lastly, the strata behaviour of the longwall face retreated along up-dip direction is demonstrated. The results of this paper improves the mechanistic understanding of the impact of face width,depth and main roof thickness on periodic weighting and associat

关键词： Longwall mining Roof weightings intervals Shield loadings Face width Cover depth

Assessment of pot-hole subsidence risk for Indian coal mines

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International Journal of mining Science and Technology 2015年第2期25卷 185-192页

作者： Lokhande D.Ritesh Murthy Vemavarapu M.S.R. Vellanky Venkateswarlu Singh B.Kalendra National institute of Technology Raipur Indian School of Mines National institute of Rock Mechanics central institute of mining and fuel research

Ground subsidence induced by extraction of coal seam belowground brings about changes in surface environment leading to trough and pot-hole ***-hole subsidence is extremely hazardous and does not give any prior indication before its *** India,several pot-holes have occurred in the coal mines of South Eastern Coalfields Limited triggering the need for in-depth *** line with the requirement,literature review and field investigations were conducted to develop an in-depth understanding of various parameters influencing the occurrence of *** critical parameters identified were rock to soil ratio,depth to height of extraction ratio,brittleness index of rock and rock *** assessment of pot-hole subsidence has been done by developing an empirical rating approach named as pot-hole subsidence rating(PHSR),involving the critical parameters with suitable corrections for certain structural and mining conditions to obtain corrected PHSR(CPHSR).CPHSR was then applied for all the 34pot-holes studied and it was found that all the pot-holes fall under Class I and Class II category of risk representing a very high to high risk *** effort was made for the estimation of pot-hole depth utilizing the developed CPHSR in both the development and depillaring *** developed approach was found to yield consistent results in pot-hole depth prediction.

关键词： Underground coal mining Pot-hole subsidence PHSR CPHSR

TGA/DSC study to characterise and classify coal seams conforming to susceptibility towards spontaneous combustion

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International Journal of mining Science and Technology 2022年第1期32卷 75-88页

作者： Niroj Kumar Mohalik Somu Mandal Santosh Kumar Ray Asfar Mobin Khan Debashish Mishra Jai Krishna Pandey CSIR-central institute of mining and fuel research(CIMFR) Dhanbad 826015India Academy of Scientific and Innovative research(AcSIR) Ghaziabad 201002India

Thermogravimetric analysis/differential scanning calorimeter(TGA/DSC)technique along with basic coal characteristics study is carried out for eighty coal samples of Indian coalfields,to determine spontaneous combustion propensity behaviour of *** study of coal samples indicates that there is an increase in the mass of coal samples in the temperature range 150-350℃,which may be due to oxygen adsorption and *** correlation and principal component analysis states that the component of proximate analysis(M_(ad),VM_(d),FR,and VR)have an acceptable correlation with the TGA experiments results i.e.,Tgsh and *** fixed nonlinear regression analysis shows that thermogravimetry(TG)experiment results Tgign may be the best index to categorise/classify the coal as per their susceptibility towards spontaneous *** authors proposed four groups of classification as per their propensity towards spontaneous combustion depending upon the moisture(M_(ad)),volatile matter(VM_(d)),and TG ignition temperature from differential thermogravimetric(DTG)curve(Tgign)using hierarchal clustering *** coal samples of different seams from Indian coalfield may be classified into four different clusters,*** highly/extremely susceptible(Tgign320℃).The field observations and TGA/DSC experiment results with the following statistical analysis substantiate a similar assessment.

关键词： Coal TGA/DSC Spontaneous combustion TG ignition

Boosting bidirectional sulfur conversion enabled by introducing boron-doped atoms and phosphorus vacancies in Ni2P for lithium-sulfur batteries

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Journal of Energy Chemistry 2025年第1期100卷 760-769页

作者： Lin Peng Yu Bai Hang Li Meixiu Qu Zhenhua Wang Kening Sun Advanced research institute of Multidisciplinary Science Beijing Institute of Technology Beijing Key Laboratory of Chemical Power Source and Green Catalysis School of Chemistry and Chemical Engineering Beijing Institute of Technology

Lithium-sulfur （Li-S） batteries have gained great attention due to the high theoretical energy density and low cost,yet their further commercialization has been obstructed by the notorious shuttle effect and sluggish redox ***,we supply a strategy to optimize the electron structure of Ni2P by concurrently introducing B-doped atoms and P vacancies in Ni2P （Vp-B-Ni2P）,thereby enhancing the bidirectional sulfur *** study indicates that the simultaneous introduction of B-doped atoms and P vacancies in Ni2P causes the redistribution of electron around Ni atoms,bringing about the upward shift of d-band center of Ni atoms and effective d-p orbital hybridization between Ni atoms and sulfur species,thus strengthening the chemical anchoring for lithium polysulfides （LiPSs） as well as expediting the bidirectional conversion kinetics of sulfur ***,theoretical calculations reveal that the incorporation of B-doped atoms and P vacancies in Ni2P selectively promotes Li2S dissolution and nucleation ***,the Li-S batteries with Vp-B-Ni2P-separators present outstanding rate ability of 777 m A h g-1at 5 C and high areal capacity of 8.03 mA h cm-2under E/S of 5μL mg-1and sulfur loading of 7.20 mg *** work elucidates that introducing heteroatom and vacancy in metal phosphide collaboratively regulates the electron structure to accelerate bidirectional sulfur conversion.

关键词： Lithium sulfur batteries

Tunnelling through weak and fragile rocks of Himalayas

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International Journal of mining Science and Technology 2014年第6期24卷 783-790页

作者： Goel R.K. CSIR-central institute of mining & fuel research Regional CentreCBRI Campus Roorkee India

A considerable amount of tunnelling has been going on in India for various projects such as hydroelectric power, irrigation, roads and railways. Most of these projects are located in Himalayas, far away from the urban areas. Tunnelling through weak and jointed rock masses such as the one in the Himalayas is a challenging task for the planners, designers, engineers and geologists because of high overburden, thickly vegetated surface, weak, poor and fragile rocks and highly varying geology with the presence of numerous small and big shear zones, faults, etc. Due to these reasons, various tunnelling problems have been faced in the past and are still being encountered. Failures and the problems may be regarded as challenges and opportunities for generating new knowledge base and thereby increasing self-reliance in tunnelling. The experiences of Himalayan tunnelling through weak and fragile rocks covering varying and mixed geology, understanding on tunnelling in squeezing ground conditions and applicability of TBM in Himalayas are presented. It has also been highlighted that the probe holes planning, drilling and monitoring shall be followed seriously to reduce the geological surprises.

关键词： Varying geology Mixed geology Weak and fragile rocks Himalayan tunnelling Ground condition Squeezing

Review of preventive and constructive measures for coal mine explosions:An Indian perspective

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International Journal of mining Science and Technology 2022年第3期32卷 471-485页

作者： Santosh Kumar Ray Asfar Mobin Khan Niroj Kumar Mohalik Debashish Mishra Somu Mandal Jai Krishna Pandey CSIR-central institute of mining and fuel research Barwa RoadDhanbad 826015India Academy of Scientific and Innovative research(AcSIR) Ghaziabad 201002India

Firedamp and coal dust explosion constitute a lion’s share in mine accidents in a global mining *** paper reports a list of mine explosion disasters since last two decades,a critical review of the different prevention and constructive measures,and its recent development to avoid firedamp and coal dust *** legislation in core coal-producing countries,***,USA,Australia,South Africa,and India related to firedamp and coal dust explosion are critically *** occurred due to explosion after Nationalisation of Coal Mines(1973)in India are *** and constructive measures adopted in India are critically analysed with respect to the global mining *** like methane credit concept,classification of mines/seams with respect to explosion risk zone,deflagration index;installation of automatic fire warning devices,canopy air curtain technology,explosion-prevention measures,such as fire-retardant materials,inhibitors,extinguishing agent,dust suppressor,and active explosion barrier are discussed in detail to avoid explosion and thereby adhering to zero accident policy due to coal mine explosion.

关键词： Firedamp explosion Coal dust explosion Preventive measures Constructive measures Legislation

Evaluation of load transfer mechanism under axial loads in a novel coupler of dual height rock bolts

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International Journal of mining Science and Technology 2021年第2期31卷 225-232页

作者： Ranjan Kumar Prabhat Kumar Mandal Ashish Narayan Arka Jyoti Das CSIR-central institute of mining and fuel research DhanbadJharkhand 826015India Chaibasa Engineering College KelendeJharkhand 833201India

The effective reinforcement of two or more overlying layers of mine openings in a single installation is usually done by coupling of two standard rock bolts mainly during the extraction of medium-thick coal ***,field observations show that the couplers of multiple bolts often degrade or break mostly at their *** types of failures can be avoided by strengthening the couplers of such multi-bolts *** achieve this,a novel threaded coupler system with an expansion shell was suggested in this *** newly designed coupler consists of a threaded tapered-plug-cumconnector with an expansion shell for connecting and tightening two standard rock *** analytical model for evaluating the load distribution along the coupler subject to axial load was *** analysis was performed to analyse the load transfer,deformation,and strains across the coupler including the factor of safety for the bolt-coupler-resin and bolt-coupler-expansion *** results validated the analytical model of the proposed coupler design,which provides better anchorage near the interface of the host rock ***,the developed coupler design would reduce the failures of the proposed coupler and stabilize laminated roof strata above the medium-thick coal seams in underground mines.

关键词： Roof rock reinforcement Dual height rock bolts Rock bolt coupler Expansion shell Underground mining Laminated roof strata

High-energy-density lithium manganese iron phosphate for lithium-ion batteries: Progresses, challenges, and prospects

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Journal of Energy Chemistry 2025年第1期100卷 1-17页

作者： Bokun Zhang Xiaoyun Wang Shuai Wang Yan Li Libo Chen Handong Jiao Zhijing Yu Jiguo Tu State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing research institute for Intelligent Wearable Systems The Hong Kong Polytechnic University institute of Advanced Structure Technology Beijing Institute of Technology

The soaring demand for smart portable electronics and electric vehicles is propelling the advancements in high-energy–density lithium-ion *** manganese iron phosphate (LiMnxFe1-xPO4) has garnered significant attention as a promising positive electrode material for lithium-ion batteries due to its advantages of low cost,high safety,long cycle life,high voltage,good high-temperature performance,and high energy *** LiMnxFe1-xPO4has made significant breakthroughs in the past few decades,there are still facing great challenges in poor electronic conductivity and Li-ion diffusion,manganese dissolution affecting battery cycling performance,as well as low tap *** review systematically summarizes the reaction mechanisms,various synthesis methods,and electrochemical properties of LiMnxFe1-xPO4to analyze reaction processes accurately and guide material ***,the main challenges currently faced are concluded,and the corresponding various modification strategies are discussed to enhance the reaction kinetics and electrochemical performance of LiMnxFe1-xPO4,including multi-scale particle regulation,heteroatom doping,surface coating,as well as microscopic morphology ***,in view of the current research challenges faced by intrinsic reaction processes,kinetics,and energy storage applications,the promising research directions are *** importantly,it is expected to provide key insights into the development of high-performance and stable LiMnxFe1-xPO4materials,to achieve practical energy storage requirements.

关键词： Lithium manganese iron phosphate High energy density Lithium-ion batteries Reaction mechanism Tap density

Depillaring of total thickness of a thick coal seam in single lift using cable bolts：A case study

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International Journal of mining Science and Technology 2016年第2期26卷 223-233页

作者： Kumar Rakesh Mishra Arvind Kumar Singh Arun Kumar Singh Amit Kumar Ram Sahendr Singh Rajendr central institute of mining and fuel research (under CSIR) Dhanbad 826015 India Indian School of Mines Dhanbad 826004 India

Explaining fundamentals of application of cable bolting for a thick seam depillaring,this paper summarizes the results of field studies conducted during adoption of this approach in more than fifteen panels of Madhusudanpur 7 pit and incline *** 7.0 m thick Kajora top coal seam of this mine is developed on pillars along the floor horizon to an average height of 3.0 m,leaving a coal band of around 4.0 m along the *** of procured core samples showed that roof strata are easily caveable with a caveability index value of around 2000 *** caveable overlying strata and shallow depth of cover alleviated most of the expected strata mechanics problems of the thick seam ***,extraction of total thickness at shallow cover caused differential-subsidence and cracks on the *** manifestations were immediately tackled to avoid creation of a breathing path for spontaneous heating in the extracted area.

关键词： Cable bolting Thick seam depillaring Extraction height Pillar stability Caveability index