Factors Influencing Proppant Transportation and Hydraulic Fracture Conductivity in Deep Coal Methane Reservoirs

The gas production of deep coalbed methane wells in Linxing-Shenfu block decreases rapidly,the water output is high,the supporting effect is poor,the effective supporting fracture size is limited,and the migration mechanism of proppant in deep coal reservoir is not clear at present.To investigate the migration behavior of proppants in complex fractures during the volume reconstruction of deep coal and rock reservoirs,an optimization test on the conductivity of low-density proppants and simulations of proppant migration in complex fractures of deep coal reservoirs were conducted.The study systematically analyzed the impact of various fracture geometries,proppant types and fracturingfluid viscosities on proppant distribution.Furthermore,the study compared the outcomes of dynamic proppant transport experiments with simulation results.The results show that the numerical simulation is consistent with the results of the proppant dynamic sand-carrying experiment.Under the conditions of low viscosity and large pumping-rate,a high ratio of 40/70 mesh proppant can facilitate the movement of the proppant to the depths of fractures at all levels.The technical goal is to create comprehensive fracture support within intricate trapezoidal fractures in deep coal and rock reservoirs without inducing sand plugging.The sand ratio is controlled at 15%–20%,with a proppant combination ratio of 40/70:30/50:20/40=6:3:1.Proppant pumping operations can effectively address the issue of poor support in complex fractures in deep coal formations.The research results have been successfully applied to the development of deep coalbed methane in the Linxing-Shenfu block,Ordos Basin.

A time-space network-based model for transportation service optimization of China Railway Express

This paper describes the development and optimization plans for the China Railway Express(CR Express).As a new type of international land transport organization,CR Express has emerged with the continuous expansion of China toward European investment and trade,and in particular,has expanded with the continuous progress of the One Belt and One Road(OBOR)initiative.In addition to improving the service quality of CR Express,the operating costs must be reduced for developing“smart railways”that serve“smart cities”.We propose a dualobjective-based function mathematical optimization model;the satisfaction of the cargo owner is considered,and the timeliness,transportation capacity,and goods category constraints of CR Express transportation are designed.Moreover,we present the normalized equivalent method of the two-objective function of the model.Finally,a case study is conducted against the background of certain trains in the western corridor of CR Express to validate the effectiveness of the model and research methods proposed in this study.

A comparison of the energy consumption and carbon emissions for different modes of transportation in open-cut coal mines

Transportation accounts for 80% of open-cut coal mine carbon emissions. With regard to the energy con- sumption and carbon emissions of transportation within an open-cut mine, this paper systematically compared the work and energy consumption of a truck and belt conveyor on a theoretical basis, and con- structed a model to calculate the energy consumption of open-cut mine transportation. Life cycle carbon emission factors and power consumption calculation model were established through a Process Analysis- Life Cycle Analysis （PA-LCA）. The following results were obtained： （1） the energy consumption of truck transportation was four to twelve times higher than that of the belt conveyor; （2） the C02 emissions from truck transportation were three to ten times higher than those of the belt conveyor; （3） with the increase in the slope angle for transportation, the ratio of truck to belt conveyor for both energy consumption and carbon emissions gradually decreased; （4） based on 2013 prices in China, the energy cost of transportation using a belt conveyor in open-cut coal mines could save 0.6-2.4 Yuan/（t kin） compared to truck transportation.

Airtight negative pressure dust-control technology and application of transpersite in the coal conveyer belt system

Presented a new coal dust control program that was airtight negative pressure dust-control technology at the transpersite,combining with analysis with the movement of air currents and numerical simulation of gas-solid flow at the transpersite,and proved the mechanism of precipitation and proliferation for coal dust-controlt in theory.The technol- ogy has made good economic results at the Heidaigou Clean Plant,not only dust concen- tration control within 10 mg/m^3 to the work site,but also substantial energy savings and cost savings.

Design and analysis of an electric-locomotive turning system for coal mines

We describe a system for turning the accumulator electric locomotives used in coal mines. This improves transport efficiency and decreases mine construction and production costs. The operating requirements, principles, working features and transmission system are discussed. This system has a simple structure and can be manufactured, transported and assembled easily. It, therefore, can handle accumulator locomotives of middle and small size.

Analysis of underground fires in Polish hard coal mines

In the period of the first twenty years after World War II the number of fires in Polish hard coal mines reached annually the value of several thousands of cases. About 80% of fires constituted spontaneous fires. Investigations into the development of new methods of fire hazard prediction and implementation of new methods and means of fire prevention as well as the introduction of prohibition concerning the use of products manufactured of combustible organic materials in underground mine workings re-duced considerably the hazard of underground fire rise. The worked out at the Central Mining Institute (GIG) new method of un-derground fire prediction allows the correct selection of fire prevention means. The introduction into common use of fire-resistant conveyor belts, the main factor giving rise to spontaneous fires, and methods of assessment of their fire resistance eliminated prac-tically the fire hazard. These activities contributed in an efficient way to the reduction of the number of underground fires to a sat-isfactory level.

Study on characteristics of pipeline transportation and sulfur fixing of cleaned coal logs

As special cylindrical briquettes of coal for long distance pipeline transportation and directly cleaned combustion the cleaned coal logs should possess two characteristics of transportation in pipeline and cleaned combustion. In order to make cleaned coal logs a rational technology for manufacturing, cleaned coal logs was designed and compound sulfur fixing binders with high effects of binding and sulfur-fixing was selected and combined. In addition, by means of characteristic experiments of strength, wear, waterproof and sulfur-fixing five different cleaned coal logs made with different compound sulfur fixing binders in different compaction conditions was tested and measured. Experimental results indicated that the manufacturing technology of cleaned coal logs was reasonable and the combination of compound sulfur fixing binders was scientific. Cleaned coal logs made up with the fourth group of coal mixture had high strength, good waterproof property, efficient sulfur-fixing, good characteristic of transportation, and achieved the performance requirement for pipeline transportation and sulfur fixing.

Advanced Strategies to Mobilize Crop Residue to Replace Coal in India

Various published data show the amount of crop residue available annually in India may range from a low of 90 to a high of 180 million tonnes. Different types of crop residue are collected from farmers depending on the geography and crop pattern for instance, in north India rice straw and cotton stalks are collected while in central India soya husk and sugarcane tops are collected. Baling and transporting straw from the field, though appear to be an option for safe disposal, will be feasible only when alternate, effective and economically viable usage methods are identified and facilities and infrastructure for ex-situ management methods are created. One immediate short term use of the residue is to replace 5% - 7% of the 670 million tonnes of coal India currently consumes to generate power. The farmers will benefit from the sale of their excess crop residue. The scheme will reduce pollution due to residue burning practices. Replacing coal will cut the GHG emissions. The challenge is to mobilize the crop residue collection and timely delivery to power plants. The data and calculations in this monogram show that it is economical for the farmer to remove the crop residue from the field quickly by using modern balers, to pelletize the biomass in small-scale distributed pellet plants, to store pellets in the modern steel bins and finally to deliver the pellets to coal plants by using rail transport. The delivered cost is estimated at around Rp 6.78/kg. The Government of India encourages the power plants to pay at least Rp 10/kg for the delivered biomass in the form of pellets. The current monogram analyzes the organization of an efficient supply chain in the State of Haryana India to ensure a sustainable modern enterprise.

Geological risk assessment of traffic engineering construction among 7.0-8.5 magnitude earthquake areas:Practice from the Sichuan-Tibet transport corridor in the eastern Tibetan Plateau

At least 13 active fault zones have developed in the Ya'an-Linzhi section of the Sichuan-Tibet transport corridor,and there have been undergone 17 MS≥7.0 earthquakes,the largest earthquake is 1950 Chayu MS 8.5 earthquake,which has very strong seismic activity.Therefore,carrying out engineering construction in the Sichuan-Tibet transport corridor is a huge challenge for geological technological personnel.To determining the spatial geometric distribution,activity of active faults and geological safety risk in the Sichuan-Tibet transport corridor.Based on remote sensing images,ground surveys,and chronological tests,as well as the deep geophysical and current GPS data,we investigated the geometry,segmentation,and paleoearthquake history of five major active fault zones in the Ya'an-Linzhi section of the Sichuan-Tibet transport corridor,namely the Xianshuihe,Litang,Batang,Jiali-Chayu and Lulang-Yigong.The five major fault zones are all Holocene active faults,which contain strike-slip components as well as thrust or normal fault components,and contain multiple branch faults.The Selaha-Kangding segment of the Xianshuihe fault zone,the Maoyaba and Litang segment of the Litang fault zone,the middle segment(Yigong-Tongmai-Bomi)of Jiali-Chayu fault zone and Lulang-Yigong fault zone have the risk of experiencing strong earthquakes in the future,with a high possibility of the occurrence of MS≥7.0 earthquakes.The Jinsha River and the Palong-Zangbu River,which is a high-risk area for geological hazard chain risk in the Ya'an-Linzhi section of the Sichuan-Tibet transport corridor.Construction and safe operation Ya'an-Linzhi section of the Sichuan-Tibet transport corridor,need strengthen analysis the current crustal deformation,stress distribution and fault activity patterns,clarify active faults relationship with large earthquakes,and determine the potential maximum magnitude,epicenters,and risk range.This study provides basic data for understanding the activity,seismicity,and tectonic deformation patterns of the regional faults in the Sichuan-Tibet transport corridor.

The Relationship between the Distribution of Thick Coal Belts and the Late Carboniferous-Early Early Permian Marine Transgression-Regression in the North China Platform

Four great second-order transgressions occurred during the Late Carboniferous to early Early Permian and they came from both the eastern and western sea areas in the North China Platform. As time went on, depocentres, depositional extent, transgression directions, coastline position and distribution of minable coal seams were changing continuously. The third great second-order transgression occurring at the beginning of the early Early Permian marks the maximum transgression period and before its arrival, i.e. at the close of the late Late Carboniferous, there was the super-regional coal-forming environment. During the second, third and fourth transgressions, the northern North China Platform was all along situated on the transgressive margin of the epicontinental sea and became the major distribution area of thick coal belts because it maintained a coal-forming environment for a long period of time from the close of the late Late Carboniferous to the Early Permian.

Investigating the Whole-lithosphere Structure of a Mineral System——Pathways and Source of Ore-forming Fluids Imaged with Magnetotelluric Modeling

Whole-lithosphere structure has direct implications for both the genesis of minerals and the locations of mineral emplacement;thus knowledge of the deep structural framework of the lithosphere can advance understanding of the development and evolution of mineral systems.

Research on management of coal bed methane warehousing and transportation based on GIS

At present Coal Bed Methane （CBM） has become the important part of clean energy in China. and will optimize the energy structure in China unceasingly. However, warehousing and transportation of CBM become one of the core factors that restrain its exploitation and utilization at present, due to the space-time character of natural deposit and modem utilization of CBM. In this paper, according to the character of CBM and the expanding trend of its utilization, the necessity of constructing the CBM＇s warehousing and transportation management system demonstrated. Index system that influence CBM＇s warehousing and transportation is established. And CBM＇s warehousing and transportation model is established by Voronoi diagram. In light of above research, CBM＇s warehousing and transportation management system based on Geography Information System （GIS） is designed, Using this system, CBM＇s warehousing and allocation center in one mining area is optimized. Research shows that to reinforce CBM＇s warehousing and transportation management is one of the key factors for coordinating the development of its development and utilization, thereby ensuring its sustainable development and utilization.

China’s BRI Transportation Investments:Development Bonanza or Debt Trap?

Based on the China Global Investment Tracker(CGIT)database of 2005-2018,this paper creates a country-sector-year panel set for a study on the BRI’s investment effects on the transportation sector of BRI countries using the difference-in-differencesin-differences(DDD)method.Our study finds that the BRI has significantly increased transportation investments by Chinese companies in the BRI countries without causing significant rise in problem transactions.The"debt trap"narrative that the BRI aims to take control over host countries’sovereign rights in exchange for debt write-offs is not supported by evidence.Discussions on sub-samples reveal that the BRI has mainly propelled SOEs in making transportation investments to generate development effects in host countries,most of which are Asian countries,and that the preferred mode of investment is cross-border M&As.

Transport phenomena in meniscus region of horizontal single belt casting

The horizontal single belt casting(HSBC)incorporating a single-impingement feeding system was simulated with an improved numerical model.Physical experiments were carried out on the pilot-scale caster for validation.The results show that the meniscus turbulence neither comes from the tundish region,nor from the impingement between the melt and the moving belt.It is the moving belt that gives rise to this high turbulence region,and this region can stir the melt near the meniscus.The feeding system studied and the moving belt give rise to a buffer region,which can optimize casting parameter variations,especially melt depth changes in the tundish.The temperature change rate of the bottom surface of the strip is around 4 times faster than that of the upper surface.

Spatial Structure Adjustment Strategies of the Coal Resource-Based Cities during the Mature Period: A Case Study of Pingdingshan

Coal cities are the main part of the resource-based cities in China, and the benign development of coal cities' spatial structure has a direct impact on these cities' future economic and social development, as well as the urban residents' welfare. Land use fragmentation is the most typical morphological characteristic of the coal city's spatial structure development. In this paper, Pingdingshan City of Henan Province in China is taken as an example. Through empirical analysis, the urban spatial structure development processes of a typical coal resource-based city in its mature period are illustrated, and the formation reasons and potential mechanism behind coal city land use fragmentation are explored, and the measurement method of land use fragmentation degree of the coal city is put forward. On the above basis, the appropriate adjustment strategies and methods aimed at the coal city spatial structure are found out and given. This study is a good guideline and reference for the spatial structure planning and land use planning of the coal city during the mature and declining period, which is of great help to the sustainable development and industrial structure transformation of the coal city. It also has certain reference significance for the coal city in the growth period.

Research of the underground coal bunker clearing robot

With the long-term use of coal bunker, a certain amount of sticking objects will beformed on its wall, and coal mine clearing robot can replace man in clearing the bunker wall.Also, since it equip with an explosion-proof camera, the worker can determine the operationby observing the well-head monitor.Moreover, it cannot work unless it is placed in positionand supported stably, and it has three degrees of freedom: rotating, stretching, and shovelcoal.It is driven by the hydraulic and controlled by PLC.The underground coal mine clearingrobot changs the traditional clearing methods, man does not have to enter the bunker toclear it, which ensures the production safety of coal transportation.

Characteristics and geological significance of germanium in Taiyuan coal formation of Huainan Coalfield,Anhui,China

HN-1#is the first fully working coring well of the Taiyuan Formation(Ty)in the Huinan Coalfield and exploration studies are currently underway on the associated resources of the coal-bearing strata.The HN-1#well is located in the Fufeng thrust nappe structural belt in the south of the Huainan Coalfield.Three coal samples from the Ty were collected from HN-1#and inductively-coupled plasma mass spectrometry and inductively-coupled plasma atomic emission spectrometry were used to determine the Ge content of each sample.Based on proximate and ultimate analyses,microscopy data,and analyses of the ash products,some important findings were made.The Ty coal samples had a relatively high total sulfur(Sud)content(4.24%),thus the coal was considered to be a lower ranked coal(high volatility bituminous coal),which also had a low coal ash composition index(k,1.87).Collodetrinite was the main submaceral of the Ty coal.Small amounts of pyrite particles were found in the coal seams of the Ty,while the contents of pyrite and algae in the top and bottom sections of the coal seam were relatively high,which meant that the swampy peat conditions which existed during the formation of the coal seams were affected by seawater;also the degree of mineralization of the coal seam was relatively high,which is consistent with reducing conditions in a coastal environment setting.Atomic force microscopy(AFM)experiments showed that the modes of occurrence of Ge in the Ty coal were mainly those for organic-bound and adsorbed Ge species.The organic carbon isotope values for the Ty coal ranged from-24.1‰to-23.8‰,with an average value of-24.0‰,which is equivalent to the value for terrestrial plants(average value-24.0‰).The Ge content of the Ty coal was 13.57 mg/kg.The Ge content was negatively correlated with volatile matter and the ash yield.

DIMINE软件在胶带排土设计中的应用

德兴铜矿废石胶带运输系统已经建成投产多年,取得了良好的经济效益。利用DIMINE软件构建排土场三维模型,并采用块段法计算排土填方量。解决了胶带排土设计中所遇到如何快速计算排土量的问题,使得胶带排土设计更加简洁、准确与高效,在现场生产管理中取得了不错的实际应用效果。

基于语义分割的带式输送机煤料运输区域检测算法

针对煤炭运输过程中,经常无法保持煤炭在带式输送机上的运量均匀,使得带式输送机长时间全速运转而造成电能浪费和设备无效磨损的问题,提出一种基于语义分割的带式输送机煤料运输区域检测算法。该算法在DeeplabV3+的基础上,根据特征通道之间的相互依赖关系,引入注意力机制,使用不同扩张率的卷积核获得多种尺度的语义信息,来精确分割出煤炭在带式输送机的运输区域。实验结果表明,该算法平均交并比(Mean Intersection over Union,MIoU)相比于DeeplabV3+算法提高1.24百分点,能够有效精准地分割出煤料的运输区域,为煤量估计工作提供有效的保障。

西北干旱露天煤矿排土场土壤重构与水盐运移机制

矿山排土场生态修复是煤矿露天开采面临的重大环境问题,是制约建设绿色露天煤矿的重要因素。土壤重构是排土场生态修复的重要步骤,以新疆为代表的西北煤炭基地,水资源短缺,盐碱化突出,土壤水盐运移是决定土壤重构是否成功的关键指标。目前研究集中在表层土壤重构改善土壤养分促进植物生长,针对保水控盐的功能化土壤重构的研究甚少,对不同土壤重构方式下的水盐运移机制尚不明晰。研究立足新疆煤炭资源禀赋特征,从煤炭循环经济的角度出发,采用能源化工副产物煤气化渣(CGS)作为重构材料,通过毛细水上升-蒸发试验,分析CGS重构后水盐垂向运移和水分供给能力,通过Van Genuchten模型拟合土壤水分特征曲线,分析CGS重构后土壤持水能力,研究CGS作为含水层重构材料的可行性。采用煤矿开采伴生岩石矿物红泥岩作为重构材料,通过土柱入渗蒸发试验,分析红泥岩重构后不同土壤深度的水盐变化情况,研究泥岩作为隔水层重构材料的可行性。结果表明,CGS重构改善土壤质地,优化孔隙结构,促进了土壤水盐运移,毛细作用增强,促进了下层水分向上供给,同时也增加了盐分表聚,重构改变土水特征曲线参数,增加了饱和含水量θ_(s),降低了参数a和n,改善了土壤持水性能。CGS添加量越高,细渣质量分数越大,效果越明显。CGS作为重构含水层材料具有可行性。红泥岩黏粒和次生矿物含量高,孔隙结构丰富,物理吸附性良好,重构后0~24 cm深度下土壤含水率高于对照组,蒸发后的盐分在20~24 cm达最高值,红泥岩有效阻隔了盐分上移。红泥岩作为重构隔水层材料具有可行性。研究以期探索出一条适合西部煤炭基地排土场土壤重构模式。