scholarly journals Study on Filling Material Ratio and Filling Effect: Taking Coarse Fly Ash and Coal Gangue as the Main Filling Component

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Changxiang Wang ◽  
Yin Liu ◽  
Hao Hu ◽  
Yangyang Li ◽  
Yao Lu
Keyword(s):  
Fly Ash ◽  
Material Selection ◽  
Orthogonal Experiment ◽  
Coal Gangue ◽  
Environmental Benefits ◽  
Filling Material ◽  
Range Analysis ◽  
Filling Materials ◽  
Filling Simulation ◽  
Main Component

Filling mining is an effective way to settle the dilemma of “Three Down and One Above” in coal mining. Fly ash and coal gangue can be used as filling materials with significant social, economic, and environmental benefits. Using coarse fly ash base as cementing material and coal gangue as aggregate, orthogonal experiment of filling paste was conducted in this study. The range analysis was performed for the strength and transportation requirements of filling paste, and the optimum proportion was determined by the comprehensive balance method. In order to verify the filling effect, a dynamic filling simulation device was designed, and a comparative simulation test of caving mining and dynamic filling mining was carried out. Results show that the filling paste with fly ash and coal gangue as the main component can meet the requirements of filling design and application. This research provides a reference for the material selection and proportion design of paste filling.

scholarly journals Effect of Concentration and Suspension Agent (HPMC) on Properties of Coal Gangue and Fly Ash Cemented Filling Material

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Baogui Yang ◽  
Junyu Jin ◽  
Xindong Yin ◽  
Xiaoyu Wang ◽  
Hongliang Yang
Keyword(s):  
Fly Ash ◽  
Coal Gangue ◽  
Filling Material ◽  
Mixture Ratio ◽  
Bleeding Rate ◽  
Slurry Concentration ◽  
Filling Materials ◽  
Slump Flow ◽  
Underground Openings ◽  
Predicted Values

Cemented coal gangue-fly ash backfill (CGFB) mixtures are utilized as the filling materials for backfilling the underground openings in coal mines. The freshly prepared CGFB slurries are commonly transported into the gobs through a pipeline. The mixture ratio of slurry concentration and suspending agent (HPMC) plays an essential role in transporting the slurry to goaf smoothly and efficiently. In this paper, the influence of slurry concentration and HPMC on the performance of coal gangue-fly ash cemented filling material was studied based on the response surface method. The prediction model of CGFB slurry slump flow, segregation rate, and bleeding rate was constructed. It is concluded that the segregation rate and slump flow of slurry are more sensitive to the variation of concentration. On the other hand, the bleeding rate of slurry is more sensitive to the change of HPMC content. Based on the established model, the reasonable mix proportion range of slurry concentration and suspending agent (HPMC) was obtained. In addition, three new CGFB mixtures have been tested, and the experimental results are in good agreement with the predicted values.

The Microstructure Research on Interfacial Transition Zone of Filling Material Containing FA and Coal Gangue

2011 ◽  
Vol 287-290 ◽  
pp. 1125-1129 ◽  
Author(s):  
Yan Yao ◽  
Hao Wu ◽  
Ling Wang
Keyword(s):  
Fly Ash ◽  
Transition Zone ◽  
Concrete Structure ◽  
Interfacial Transition Zone ◽  
Coal Gangue ◽  
Mineral Admixture ◽  
Filling Material ◽  
Filling Materials ◽  
Durability Performance

Interfacial transition zone (ITZ) is the weakest part in concrete structure because of the interrelation between its special characters and the performance of concrete, and adding mineral admixture in concrete is a feasible and effective way to improve ITZ. The workability, mechanical and durability performance of filling materials with Fly ash and Coal gangue has been invesitgated, and the interrelation has been research in a micro view by means of SEM and EDS.

Effects of Coastal Coal Gangue Highway on Groundwater

2013 ◽  
Vol 838-841 ◽  
pp. 2518-2521
Author(s):  
Shuang Jian Jiao ◽  
Shuai Wang ◽  
Feng Zun Luo
Keyword(s):  
Inorganic Salt ◽  
Salt Content ◽  
Coal Gangue ◽  
Environmental Benefits ◽  
Ecological Environment ◽  
Filling Material ◽  
Leaching Test ◽  
Regulatory Requirements ◽  
Land Expropriation ◽  
Annual Discharge

At present, the cumulative coal gangue piles up about 4.5 billion tons and annual discharge capacity reaches 300 million tons in China. Emissions of coal gangue wastes national resources and will take up a lot of land. Besides, the ecological environment will be polluted and damaged. Using coal gangue as roadbed filling material can not only solve the difficulty of land expropriation, but also consume a large amount of accumulated coal gangue, which has huge economic and environmental benefits. Through laboratory soak test and leaching test, this paper analyses the inorganic salt content and heavy metals of coal gangue used in Xing Fen expressway. Groundwater in Xing Fen highway was captured, detected, evaluated and its quality was good or excellent. In this project, the effects of coal gangue on groundwater meet the regulatory requirements and coal gangue as a new filler can be applied to coastal highway roadbed.

scholarly journals Influential Factors in Transportation and Mechanical Properties of Aeolian Sand-Based Cemented Filling Material

Minerals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 116 ◽  
Author(s):  
Nan Zhou ◽  
Haobin Ma ◽  
Shenyang Ouyang ◽  
Deon Germain ◽  
Tao Hou
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Cement Content ◽  
Ash Content ◽  
Influential Factors ◽  
Filling Material ◽  
Aeolian Sand ◽  
Early Hydration ◽  
Filling Materials ◽  
Slag Content

Given that normal filling technology generally cannot be used for mining in the western part of China, as it has only a few sources for filling gangue, the feasibility of instead using cemented filling materials with aeolian sand as the aggregate is discussed in this study. We used laboratory tests to study how the fly ash (FA) content, cement content, lime–slag (LS) content, and concentration influence the transportation and mechanical properties of aeolian-sand-based cemented filling material. The internal microstructures and distributions of the elements in filled objects for curing times of 3 and 7 days are analyzed using scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The experimental results show that: (i) the bleeding rate and slump of the filling-material slurry decrease gradually as the fly ash content, cement content, lime–slag content, and concentration increase, (ii) while the mechanical properties of the filled object increase. The optimal proportions for the aeolian sand-based cemented filling material include a concentration of 76%, a fly ash content of 47.5%, a cement content of 12.5%, a lime–slag content of 5%, and an aeolian sand content of 35%. The SEM observations show that the needle/rod-like ettringite (AFt) and amorphous and flocculent tobermorite (C-S-H) gel are the main early hydration products of a filled object with the above specific proportions. After increasing the curing time from 3 to 7 days, the AFt content decreases gradually, while the C-S-H content and the compactness increase.

Study on the Properties of Pumping Gangue Filler

2011 ◽  
Vol 287-290 ◽  
pp. 1164-1167
Author(s):  
Yue Zhong Lin ◽  
Dong Cai Lin
Keyword(s):  
Fly Ash ◽  
Research And Development ◽  
Portland Cement ◽  
Coal Gangue ◽  
Filling Material

As reinforcement of goaf filling needs, filling material mined area become the focus of research and development. This study used PO42.5 Portland cement, fly ash, coal gangue, preparation meets the requirements of good performance out of the strength of pumping gangue filler.

scholarly journals Development of Coal Mine Filling Paste with Certain Early Strength and Its Flow Characteristics

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Feng Zhang ◽  
Jinxiao Liu ◽  
Haiming Ni ◽  
Wenxin Li ◽  
Yongle Liu
Keyword(s):  
Fly Ash ◽  
Coal Mine ◽  
Setting Time ◽  
Flow Characteristics ◽  
Coal Gangue ◽  
Practical Significance ◽  
Range Analysis ◽  
Factors Affecting ◽  
Early Strength ◽  
Backfill Strength

In coal mine paste filling technology, geomaterials like coal gangue and fly ash are used as the main component, and cement is applied as the cementing material. In the mining production, mining-and-filling is a cyclic work, where the filling immediately after mining and mining immediately after filling. Long solidification time after filling will affect mining; consequently, the paste should have early strength. In addition, the prepared paste will be conveyed to goaf through the pipeline. The paste flow characteristics will change to some extent in the conveying process, and there is uncertainty about whether the paste can meet the requirements of pumpability and strength. Therefore, the influence of pipeline conveying on flow characteristics of paste before filling the goaf should be taken into consideration. Based on the above two points, this paper studies the paste strength, backfill strength, and pumpability parameters in coal mine paste filling and determines the early and later strength of coal mine paste, as well as the pumpability parameters such as slump degree, segregation degree, setting time, and paste gradation. With the determined mass proportion of coal gangue, fly ash, and silicate cement, the orthogonal test was carried out with three factors including gypsum content, the content of early strength agent (Na2SO4), and the mass concentration, and at three levels. The factors affecting paste flow characteristics were determined by range analysis, and the factors affecting the paste’s early strength were determined by the XRD test and SEM test on its microstructure. With paste proportioning and pipeline conveying simulation system, taking slump, segregation degree, backfill strength, and other parameters as indicators, we obtain the influence law of pipeline conveying on the flow characteristics of paste. The research has great theoretical and practical significance for developing coal paste with early strength and its flow characteristics.

Experimental Study on Mine-Loess and Fly Ash Backfilling Material

2014 ◽  
Vol 1010-1012 ◽  
pp. 1518-1522 ◽  
Author(s):  
Kai Hua Sun
Keyword(s):  
Fly Ash ◽  
Coal Mine ◽  
Orthogonal Experiment ◽  
Weight Ratio ◽  
Solid Material ◽  
Mining Area ◽  
Filling Material ◽  
Optimal Range ◽  
North West ◽  
Four Levels

In order to reduce the cost of backfilling materials in north-west mining area, the feasibility of making the loess as backfilling material in coal mine was discussed in this paper, an orthogonal experiment were conducted and the ratio of backfilling material is gained by author. The experiment was based on the material as main material: loess with fly ash, auxiliary material:cement with lime and other additive agent. According to the mechanism of alkali excitation on the potential activity of the fly ash , a four levels and five factors experiment was conducted by using the orthogonal principle, to analyze the influence of various factors on the main indicators of material specimen, the new material ratio that meet the requirements of backfilling is obtained. Experimental results indicate that: it's feasible to make the loess with fly ash as filling material in coal mine, the appropriate slurry concentration is 60% ~ 65% and the optimal range of the weight ratio of loess with fly ash is 1:1.5~1:3, the optimal range of the weight ratio of auxiliary materials with solid material is 30%~33% and 5%～7% of additive dosage respectively, the appropriate curing time is 28 days.

Preparation System Design of Filling Material with Coal Gangue as Coarse Aggregate

2011 ◽  
Vol 361-363 ◽  
pp. 135-138
Author(s):  
You Xia Sun ◽  
Da Wei Ren
Keyword(s):  
System Design ◽  
Coarse Aggregate ◽  
Economic Benefits ◽  
Coal Gangue ◽  
Environmental Benefits ◽  
Filling Material ◽  
Industrial Experiment ◽  
Social Environmental ◽  
The Cost ◽  
Safety And Stability

Based on green mining idea, this paper developed a kind of filling material with coal gangue as coarse aggregate and designed underground-preparation system with the main processes being breaking, mixing and pumping. As a result of the research, the coal gangue pollution and surface subsidence problem was effectively solved and the load of lift transportation system reduced and the cost of filling technology cut down, which meet the concept of green mining. The industrial experiment verified the safety and stability of the system which can improve enterprises economic benefits and social environmental benefits.

Experimental Research on Durabilities of Coal Gangue Concrete

2011 ◽  
Vol 306-307 ◽  
pp. 1569-1575 ◽  
Author(s):  
Jin Min Guo ◽  
Ling Li Zhu
Keyword(s):  
Fly Ash ◽  
Experimental Research ◽  
Compression Strength ◽  
Modulus Of Elasticity ◽  
Orthogonal Experiment ◽  
Sem Analysis ◽  
Coal Gangue ◽  
Freeze Thaw ◽  
Basic Properties ◽  
Loss Of Strength

Basing on basic properties of coal gangue from No.1 mine of Pingdingshan Tian’an coal group, authors made coal gangue concrete with coal gangue instead of some aggregate, fly ash and slag instead of some cement. Coal gangue concrete was studied by the method of orthogonal experiment. Compression strength, its loss of strength after corrosion by sulphate, modulus of elasticity and its loss after freeze-thaw were analyzed. Optimum mix of coal gangue concrete was given by the integrated balance method. And Finally, SEM analysis on coal gangue concrete was researched. According to the experiment, Sulfate attacking on coal gangue concrete was little.

scholarly journals Development of Filling Material with Fly Ash and Slag as Lubricant in Pipe Jacking Under Acid Sulfate Soils

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Kazuki MAEHARA ◽  
Hideki SHIMADA ◽  
Takashi SASAOKA ◽  
Akihiro HAMANAKA
Keyword(s):  
Fly Ash ◽  
Frictional Resistance ◽  
Filling Material ◽  
Acid Sulfate Soils ◽  
Acid Sulfate ◽  
Filling Materials ◽  
Pipe Jacking ◽  
Negative Impacts ◽  
Trenchless Construction ◽  
Sulfate Soils

The pipe jacking method is relatively reasonable among trenchless construction methods.For the application of this method, the acid sulfate soils have negative impacts on filling materials (one of the cement materials) injected into the tail-void which are over-cutting areas formed to reduce the friction between the pipes and the surrounding soils. In thisstudy, the application of fly ash and slag is discussed to minimize the effect of sulfur acid to filling materials. As the results of the experiments, the addition of fly ash and slag can control the gelling time and prevent the reduction of uniaxial strength of filling materialsunder the acid sulfate soils. In addition, the filling materials added slag lowered frictional resistance compared to that of fly ash. Fillingmaterials with the lower frictional resistance are preferred to apply for the smooth pipe jacking constructions. Therefore, filling materials added slag would show better performance than that of fly ash under the acid sulfate soils due to its lower frictional resistance.

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