where d is the particle size of the broken coal gangue, mm; D is the largest particle size of the broken gangue, mm; M d is the mass of broken gangue in the rock sample with a particle size smaller than or equal to d, g; M t is the total mass of broken gangue in the sample, g; and n is the Talbol power exponent. 2.2 Test procedure The above crushed rock mass …Web
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The compaction and breakup characteristics of crushed coal rock masses during stress recovery in the strata and its series of influencing factors (e.g., particle size, strength, temperature, and moisture) have been investigated in detail (see Table 1, Table 2). ... Results demonstrated that with the increasing temperature, the size of cracks on ...Web
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Vibrating grizzly or roller screens are provided upstream of the crushers for less than 25 (typical) mm coal particles bypass the crusher and coal size more than 25 mm then fed to the crushers. The crushed coal is either fed to the coal bunkers of the boilers or discharged to the coal stockyard through conveyors and transfer points, if any.Web
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dimensions. The coal sample mass was measured using the digital scale with 0.001 kg resolution. The experiments were performed for different size classes presented in Table 1. Table 1. Measurement and calculated results for coal particle size classes. Size class [mm] Mass [kg] Volume [m 3] Bulk density [kg/m ] 80 – 160 7.076 0.0106 724Web
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This applies when the screen will remove less than 95% of the coal that is finer than the opening size of the screen. It can be estimated from the equation J = 4.4 − 3.6 fraction of fines to be removed. Example calculation. A coal is to be screened at 0.5 inches (1.27 cm). The desired feed is 500 tons/h, with 50% of the material coarser than ...Web
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This method relates to the repeated release of the drop hammer to crush the coal body. The particle size distribution of the crushed coal sample is analyzed, and the new surface area of the crushed coal sample can be calculated. The calculation formula is as follows [35]: (5) W = k 1 m H g h H n (6) Γ = W Δ SWeb
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The crushed coal was divided into three types through screening, with particle sizes of 5–10 mm, 10–15 mm and 15–20 mm, to represent different crushing degrees, as shown in Fig. 4.The grouting device was assembled, and an oily cement release agent was daubed on the inner wall of the grouting chamber and the plates.Web
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1 Scope. This International Standard provides description of a cone procedure for determining an uncompacted bulk density of crushed coal less than 37 mm in size, such as is charged into coke ovens. It focuses on the uncompacted bulk density of coal resulting from flowing the material into a measuring container (box) in the absence of ...Web
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Solid backfill coal mining is a new method of green mining in which backfill material is transported by a special handling system and processed through a tamping device behind a hydraulic support at the mining face. ... The particle size distribution of the crushed waste rock specimens after compressive loading has superior fractal ...Web
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The accurate determination of permeability is one of the parameters essential for the study of fluid flow and transport state. However, a large number of fractured coal bodies are faced during the production of coal mines. The study of permeability of these special media composed of grains of a certain size, whose structure is different from that …Web
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The fact that about 83 % of the crushed coal was contributed by +3 mm size fractions (Table 3) showing little liberation, is important. On crushing subsequently by the same DRC to nominal top size of −10 mm, as high as 74 % of the crushed coal reported to +3 mm size fractions.Web
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The results showed that the particle size distribution of coal gangue samples exhibited fractal characteristics, and the fractal dimension increased with the increase in the small particle content, and tended to a certain value. ... Guo, W.B. Experiment study of compaction characteristics of crushed stones from coal seam roof. Chin. J. Rock ...Web
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Crushed Coal: Some power plants, especially older ones, may use crushed coal rather than pulverized coal. In this case, the coal is crushed into a smaller size, typically around 1 inch (25mm) or ...Web
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The particle size distributions of crushed coal at room temperature and ∼100 kPa are shown in Fig. 4. Although the particle sizes of the original screened coal particles were between 5 mm and 10 mm, the initial particle size for statistical analysis is 7 mm.Web
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With the decrease of the particle size of the crushed tectonic coal under the unloading confining pressure, the volume of gas desorption and the desorption speed increase gradually. Combined with the analysis of PSD, it is found that the tectonic coal crushed at a faster unloading speed of confining pressure has a higher gas desorption …Web
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The gas seepage properties of crushed coal specimens with five particle sizes of a (2.5–5 mm), b (5–10 mm), c (10–15 mm), d (15–20 mm) and e (mixed sizes) under the variable axial displacement of 10, 15, 20, 25, 30, 35, and 40 mm, respectively are measured by the revised MTS815.02 system. The results of test show that: The porosity ...Web
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Section snippets Theory (1) Concept definition. A broken coal rock body is divided into two categories: the stacked-crushed coal rock body, such as the coal and gangue that emerged from the mining area, etc., the structure is looser and forms a natural stacking state [17,18] and the local-crushed coal rock body, such as the crushed …Web
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A SANS testing machine was developed to investigate the energy dissipation of crushed coal gangue from filling material (Zhou ... Li YL (2018) Bearing deformation characteristics of large-size broken rock. J China Coal Soc 43:1000–1007. Google Scholar Zhang C, Tu SH, Zhao YX (2019) Compaction characteristics of the caving zone in a …Web
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A run-of-mine coal (58.5% ash) was crushed to -75 mm and screened into six size fractions. The individual size fractions and the composite coal -75 +0.5 mm were …Web
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the coal-bearing stratum is Middle Jurassic Yan'an Group (J2y), 8 coal is the main mineable coal seam in the area, 8 coal seam in the area drilling reveals burial depth 101.25 ~ 701.62m, averageWeb
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A lateral limit compression test with the crushed coal bodies was carried out to illustrate the effect of the porosity on the permeability, In addition, a compressive …Web
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Depending on the nature of the coal and of the planned processing, during mining the largest lumps may be broken to a topsize as large as 200 mm, or as small as …Web
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Crushing efficiency has been defined in the literature from the power consumption point of view. But while operating a process plant, it is more important that the crushing efficiency is defined in terms of the requirement of subsequent process. The Process plant has been designed for coal size - 13 mm ( 80 % passing).Web
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Meantime, under the action of axial stress, coal samples were broken into more smaller size particles which effectively filled the coal mass gaps; after experiencing the cyclic process of compaction–crushing–compaction, the porosity and the permeability of the crushed coal tend to be stable values.Web
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For tectonic coal particles from two coal mines with a size range of 2–3 mm, a total of 67 sets of crushing experiments were performed under various gas adsorption pressure (0.5–4.0 MPa) and desorption duration (1–240 min) conditions. The fractal theory was used to analyze the particle size distributions of the fragments.Web
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The permeability of crushed coal gangue follows a hierarchical distribution law and the permeability changes in the magnitude range of 10–11 ~ 10–9 m2. The fractal dimension is inversely related to the permeability of crushed coal gangue. ... Among them, the particle size ranges of coal gangue are 2.5–5 mm, 5–8 mm, 8–12 mm, and 12 ...Web
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Taking the low-rank lignite as an example, which is the most prone to spontaneous combustion, an analysis was conducted on the oxidation reactivity after the coal was crushed to five different particle size ranges: 0.224−0.280 mm, 0.180−0.224 mm, 0.125−0.180 mm, ConclusionsWeb
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First, we conducted N2 and CO2 adsorption tests on coal chunks and crushed coal (60 mesh particles) of primary structure coal and ductile TDCs (Ro, max = …Web
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The crushed rocks used in this study were taken from Haragou Coal Mine, Daliuta Town, Shenmu County, Shaanxi Province, with a size range of 5–45 mm and a solid density of 2300 kg/m 3 (Figure 1a). The crushed rocks were divided into 8 groups based on particle size sieving, with each group having a particle size interval of 5 mm.Web
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Anthracite is the form of coal containing the highest percentage of carbon. Three classes are distinguished: Name Fixed Carbon (percent) Volatile Matter (percent) meta-anthracite >98% <2%: anthracite: ... Size Screen sizes, inches (through and over) egg: 2.5 to 1.75: stove: 1.75 to 1.25: chestnut: 1.25 to 0.75: peas: 0.75 to 0.50: …Web
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After the coal body is crushed to a smaller particle size, the effects of oxidation and crushing on the coal free radical concentration are continuously strengthened. The oxidation and crushing effects are both strongest …Web
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Variation laws for particle size gradation of the crushed coal particles. The crushed coal particles obtained from the compression experiments under different conditions were manually sieved and weighed. Fig. 5a exhibits the comparison for the particle size gradation (PSG) curve of the the pre- and post-compacted coal samples. ...Web
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Four types of crushed anthracite with single particle sizes of 2.5–5, 5–10, 10–15, and 15–20 mm were used to investigate the effect of particle size on the internal re-crushing characteristics. 3. Experimental results and discussion. 3.1.Web
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Five standard screens with apertures of 3 mm, 1 mm, 0.25 mm, 0.2 mm, and 0.074 mm were used to screen the crushed coal samples. The coal samples with the …Web
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The coal specimens in the laboratory were broken into smaller particles that were less than 37.5 mm. Using different sieve sizes, the crushed coal gravels were graded into six groups with different grain size ranges, …Web
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Further refinement of coal particle size can enhance the yield of vitrinite with lightweight, which is less dense due to its lower aromatization than inertinite. ... IC belongs to coking coal, and NC belongs to gas coal. The raw coal crushed by the coal mill was subjected to wet sieve test according to 0.5–1.0 mm, 0.25–0.50 mm, 0.125–0. ...Web
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Xu [9] used crushed gangue, limestone, and gypsum as the main materials and fluorite and barite as the secondary materials and prepared an alite-sulfoaluminate cement at 1330 C. The results showed that the compressive strength of the cement after 7 days was 48.9 MPa. Wang [10] prepared a new biochar composite material using …Web
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To investigate the permeability characteristics of this special porous medium composed of crushed coal particles, the permeability parameters of crushed coal …Web
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