Enhancing potential of hydrofracturing in mylonitic coal ... · Mylonite coal is a representative of tectonically deformed coal and is a result of crushing original coal into fine coal grains under strong shear or longlow tectonic stress. Because of its granular nature and the resultant inferior mechanical property, it is difficult to initiate fluiddriven fractures within mylonitic coal reservoirs for enhancing coalbed methane recovery. The following ...
Dynamic characteristics analysis on shearer drum in ...Comparing with the single conical pick and coalrock model in Fig. 3, the model of shearer drum in Fig. 4 was not only improved with several conical picks, fixed base and helical blade, but also taken many kinds of factors into account and these factors were shown in Table 2. For this reason, the shearer drum model is much closer to the real working environments and it is more reliable than ...
Experimental study of stress–permeability behavior of ... · · Thus, for the vertical single fracture coal samples in this paper, the better stress ... causes of the permeability loss in the late loading–unloading stage were the fracture surface crushing and pulverized coal recrushing because of high intensity repeated loading, as shown in figure 11. Figure 13. Open in new tab Download slide. Experimental results for the F1 sample after the .
Experimental study of stress–permeability behavior of ... · Thus, for the vertical single fracture coal samples in this paper, the better stress ... causes of the permeability loss in the late loading–unloading stage were the fracture surface crushing and pulverized coal recrushing because of high intensity repeated loading, as shown in figure 11. Figure 13. Open in new tab Download slide. Experimental results for the F1 sample after the second and ...
Effect of foreign minerals on sulfur transformation in the ... · The coal with larger particle size has more sulfur residue in char. • Fe 2 O 3 mainly affects the sulfur migration from gas to solid during coal pyrolysis.. MgO, NaOH, and KOH have no sulfur fixation effect. • Sulfur fixation effect of CaO is lower than that of Fe 2 O 3 in pyrolysis stage.. CaSO 4 as the combustion products of CaS is more stable and can be fixed in ash.
(PDF) Method Extraction of Lower and Upper Coal Seam in ...The evaluation was carried at two stages of mining, at development stage and after extraction of two and a half pillars with a single rib left. I. CONTIGUOUS SEAMMINING The working of the seams may get affected if the distance between the seams is small. If there are two seams in such a manner that one seam is directly above the other one being worked, then the working in the top seam ...
Crushers and Their Types – IspatGuru · For example, single roll crushers employ shear together with impact and compression. Shear crushing is normally called for under the conditions when material is somewhat friable or when a relatively coarse product is desired. It is usually employed for primary crushing with a reduction ratio of 6 to 1. Compression – As the name implies, crushing by compression is done between two surfaces ...
Effects of gradation and grain crushing on the ... · Meanwhile, the effects of grain crushing are also discussed in combination with the characterization of the microstructure based on microcomputed tomography (microCT). Hence, a total of 46 tests were carried out to explore the dynamic behavior of calcareous sand under undrained conditions based on the variation in CSR, relative density, and confining pressure for different gradation states.
SUITABILITY STUDY OF SURFACE MINER IN INDIAN COAL MINESEffect of utilization of surface miner on economics of mine. Effect of disposition of surface miner on the quality of coal. What is the assessment of environmental effect due to placement of surface miner in the mine. Suitability for overview of surface miner in Indian geomining circumstances. REASONING FOR THE STUDY: As I have already mentioned that the earlier used conventional system of ...
Study on the characteristics of nitrogen dioxide ... · Put the coal sample into a ball mill for crushing, then sieving, put the coal sample smaller than 50 mesh into a reagent bottle, label it, and then put it in a vacuum drying box for storage.
University of Wollongong Research Onlinefrom coal by crushing. This technique allows the determination of gas content in the space of hours rather than days or weeks as required for the traditional slow desorption technique. The crushing technique is used particularly when gas content determinations are urgently required for mine safety purposes. The method is now routinely used in underground coal mines of NSW and to a lesser ...
Coal · Coal shearing machines known as "continuous miners" remove a long wall of coal in a single slice as hydraulic jacks hold up the roof above and in front of the machine. Once this coal has been extracted, the continuous miner and hydraulic jacks advance, and overlying rock collapses into the void behind. This occurs 4001,000 feet below the surface, causing subsidence to both natural ...
Energies | Special Issue : Clean Utilization and ... · All manuscripts are thoroughly refereed through a singleblind peerreview process. A ... This paper presents analysis of the results of tests on crushing, coal briquettes, and grinding coal blend in selected mechanical systems. Results of tests on coke quality (CRI, CSR) in connection with the grain size triangle are discussed. Full article (This article belongs to the Special Issue Clean ...
University of Wollongong Research Onlinein crushing efficiency and rate of gas release, shown in Figure 9. Further investigation also confirmed differences in crushing equipment used at two separate gas test laboratories. As shown in Figure 10 and Figure 11 respectively, Lab 1 uses twin puck and Lab 2 uses a single puck arrangement in the bowls of their ring mill crushers.
CrusherIn the coal industry, which grew up hand in hand as the preferred fuel for smelting ores, crushing and preparation (cleaning) was performed for over a hundred years in coal breakers, massive noisy buildings full of conveyors, beltpowered triphammer crushing stages and giant metal grading/sorting grates. Like mine pumps, the internal conveyors and triphammers contained within these 7—11 ...
Effect of Crushing and Strain Rate on Mechanical Behavior ... · · Effect of crushing on stressstrain behavior of typeF fly ash with different degrees of crushing (S0S4) was evaluated by performing UU triaxial tests. The uncrushed specimen (S0) showed brittle behavior with sudden drop in the peak stress post failure for all confining pressures (100, 200, and 300 kPa). On the other hand, S2 to S4 specimens exhibited less brittle/more ductile .
Effects of pyrite on the spontaneous combustion of coal ... · · Coal samples were prepared using twostage crushing. In the first step, raw coal was crushed to a maximum size of 10 mm and a 8 kg sample was collected for mixing with the pyrite for the temperatureprogrammed experiment. The particle size of the rest of the coal was then reduced to minus mm by secondary crushing. The sulfide used in all the tests was pyrite (FeS 2) .
Coal char characteristics variation in the gasifiion ... · Up to now, most of the studies have focused on single coal or single gasifiion agent, while few studies concentrate on the structure and pore changes of large particle lump coals, especially for those of various ranks coal in different gasifiion agent. In this study, the gasifiion of coal samples from Inner Mongolia, Xinjiang, and Hancheng were taken as examples to illustrate the ...