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An rescaled range analysis on the characteristics of coal seam development in the Eastern depression
The characteristics of coal seam development, and the prospects of a favorable coal-forming area, were evaluated for the Liaohe Basin located in China. The Number 3 and Number 9 coal seam thickness series from 60 nearly equally spaced bores in the Eastern depression of the Liaohe Basin were examined by a rescaled range analysis. The results indicate that the Hurst exponents of the Number 3 and Number 9 coal seam thickness series are 0.69 and 0.68, respectively. This suggests the presence of persistence. As the bore spacing increases the Hurst exponent of the Number 3 series gradually decreases (H changes from 0.69 to 0.52) and shifts from persistence to randomness. The Hurst exponent of the Number 9 thickness data gradually increases (H changes from 0.68 to 0.91) and always shows the characteristic of persistence. A combination of geological characteristics and the series data allow the conclusion that it is more suitable for the Number 9 coal seam to form in the Northeastern part of the Eastern depression than the Number 3 coal seam....
2020-06-12 16:18:46浏览：1427
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Element geochemistry and cleaning potential of the No. 11 coal seam from Antaibao mining district
Based on the analyses of sulfur and 41 other elements in 8 channel samples of the No. 11 coal seam from Antaibao surface mine, Shanxi, China and 4 samples from the coal preparation plant of this mine, the distribution of the elements in the seam profile, their geochemical partitioning behavior during the coal cleaning and the genetic relationships between the both are studied. The conclusions are drawn as follows. The coal-forming environment was probably invaded by sea water during the post-stage of peatification, which results in the fact that the contents of As, Fe, S, etc. associated closely with sea water tend to increase toward the top of the seam, and that the kaolinite changes into illite and montmorillonite in the coal-sublayer near the roof. These elements studied are dominantly associated with kaolinite, pyrite, illite, montmorillonite, etc., of which the As, Pb, Mn, Cs, Co, Ni, etc. are mainly associated with sulfides, the Mo, V, Nb, Hf, REEs, Ta etc. mainly with kaolintie, the Mg, Al etc. mainly with epigenetic montmorillonite, and the Rb, Cr, Ba, Cu, K, Hg, etc. mainly with epigenetic illite. The physical coal cleaning is not only effective in the removal of ash and sulfur, but also in reducing the concentration of most major and trace elements. The elements Be, U, Sb, W, Br, Se, P, etc. are largely or partly organically bound showing a relatively low removability, while the removability of the other elements studied is more than 20%, of which the Mg, Mn, Hg, Fe, As, K, Al, Cs, and Cr associated mostly with the coarser or epigenetic minerals show a higher removability than that of ash. The distribution of the elements in the seam profile controls their partitioning behavior to a great degree during the coal cleaning processes....
2020-06-12 16:18:45浏览：1432
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E24 profile slope stability analysis in Haizhou Opencast Coal Mine of Fuxin
The E24 profile slope analyzed belongs to a series of excavated slopes of the Haizhou Opencast Coal Mine. It seems to be divided into Downslope Part and Upslope Part. Its profile comprises two noticeable coal seams, called the 8# and 9# weak layers, considered as the potential failure surfaces. In consideration of the actual configuration as in the perspective of any modification, assessing the stability of this slope with various profile forms under given conditions, and assessing the risk of instability and quantifying the influence of earthworks or other modifications to the stability of this slope, have constituted the primordial objectives carried out. From assumed potential failure surfaces, any specific profiles and specified slip surfaces are defined. A factor of safety (FoS) is computed for each specified slip surface; the smallest FoS found corresponds to the least favorable slip surface. The safety factor values obtained are compared to the suggested safety factor. Limit equilibrium methods of vertical slices implemented in Slope/W, computer program for slope stability analyses, have been adopted to perform the E24 slope stability analysis. The safety factor values computed with 9# weak layer are lower than for 8#; the factors of safety obtained with Sarma's method are the smallest; more, without groundwater (long term) overall values are greater than those determined under groundwater condition (short term). The lowest safety factor value is found for a profile depending on an adopted earthwork sequence. The E24 profile slope stability analysis shows the instability risk for the deepest weak layer, and also shows the short and long term stability of this slope for the envisaged earth movements. However it demonstrates the existence of instability risk for any earthwork firstly affecting the downslope part....
2020-06-12 16:18:44浏览：1445
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63. Study on the deletions of the FHIT gene mRNA in murine lung cancer induced by Coal Tar Pitch
Epidemiological studies have shown that people who were exposed to Coal Tar Pitch (CTP) had a higher incidence of lung cancer than control population. In addition, CTP could induce two kinds of lung cancer in rats and mice. Although CTP is widely considered as a definite carcinogen, the mechanism of carcinogenesis is still unknown. Ohta discovered a new gene-FHIT (Fragile histidine triad) by exon-capture technique in 1996. It was reported that this gene was closely associated with the environmental carcinogen. FHIT gene is a focus for the study of environmental carcinogen acted upon. In our experiment, CTP was heated directly to produce fume to set an environment simulating workplace. Experimental mice were forced to inhale fume of CTP to induce model of lung cancer. Through series killing, the deletion of FHIT gene during tumor genesis was studied. The purpose of this study is to investigate whether the molecular genetic event can be used to detect primary lung cancer. It can also provide useful information to infer the FHIT changes in human lung tumor genesis.
Methods and materials: 64 Kunming mice were provided by Henan Laboratory Animal Center. They were 4 weeks old and half were male. All the mice were randomly divided into experimental and control groups. Each group had 32 mice. Experimental material was Coal tar pitch, which was produced by Beijing Certain Steel Factory. Experimental mice were put into 50 liter sealed vessel, which the fume was blown into by circulating system, the CTP was heated by electric hot plate at 400℃ until CTP did not produce fume. During experimental period, mouse's diet habit and activities were recorded. The mice in experimental group were exposed to CTP fume for 12 weeks, then half of the mice were executed after stopping inhale CTP fume, the rest were executed in 24th weeks. The wet weight of lung and liver were measured. The specimen of lung was divided into two parts. One part was fixed by 10% formalin. The other was frozen in liquid nitrogen. The murine cDNA sequence was found in GenBank. The primers were devised by Primer Devising software. The targeted DNA fragment was amplified by nested-PCR. The expected length of product was 694bp.
Results: ①The diet habit and activities of mice in experimental group were normal, the weights of the mice in the experimental groups were 32.83±5.40 gram and 38.34±5.47 gram in 12th weeks and 24th weeks respectively. There were significant loss compared to the control group mice. The index of lung and body in experimental group was increased significantly compared to control group. ②The main histology type of lung cancer induced by CTP fume was carcinoid (87.5%). In experimental group, there were 2 cases of carcinoid occurred (2/16) in 12th week, whereas there were 5 cases and 1 case of adenocarcinoma occurred in 24th weeks. However, there was no any cancer occurred in control group. ③Deletions of FHIT transcripts were found in the tissue of precancerous lesion, tumor lesion and its adjacent tissues. Nested-PCR results show that 52% PCR products exhibited aberrant bands in the exposure group. Among 8 mice with tumors, aberrant bands were shown in 4 carcinoids mice, 5 of 7 precancerous specimens showed aberrant bands. Except for the wild-type 694bp band, there were one or two aberrant bands, which were shorter than normal band. The length of deletions was 100bp or so. Aberrant transcriptions were not detected in control group.
Conclusions: ①The main histological type of lung cancer induced by CTP was carcinoid. This finding indicates that the CTP fume can specifically cause mouse carcinoid. ②Aberrant FHIT transcripts were detected consistently, from precancerous lesion to tumor specimen, which suggests that abnormality of FHIT gene transcript is an early and frequent molecular genetic event and this change can last to the occurrence of tumor. The finding is valuable for early diagnosis....2020-06-12 16:18:43浏览：1432
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Beneficiation of Titanium Oxides From Ilmenite by Self-Reduction of Coal Bearing Pellets
The study on the beneficiation of titanium oxides from Panzhihua ilmenites by reduction of coal bearing pellets was carried out. The iron oxides in pellets were efficiently reduced to metal iron, and titanium oxide slag beneficiated was separated from metal iron. The effect of temperature, flux and coal blending ratio on the reduction and separation was investigated, and rational parameters were determined. A new process for the beneficiation of titanium oxides by rotary hearth furnace (RHF) was proposed....
2020-06-12 16:18:39浏览：1400
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Expression of Hsp27 and Hsp70 in Lymphocytes and Plasma in Healthy Workers and Coal Miners with Lung
In coal mines, main occupational hazard is coal-mine dust, which can cause health prob-lem including coal workers' pneumoconiosis and lung cancer. Some heat shock proteins (Hsps) have been reported as an acute response to a wide variety of stressful stimuli. Whether Hsps protect against chronic environmental coal-mine dust over years is unknown. It is also interesting to know that whether the expression of Hsp27 and Hsp70 proteins as a marker for exposure is associated risk of lung cancer among coal miners. We investigated the association between levels of Hsp27 and Hsp70 expression in lymphocytes and plasma and levels of coal-mine dust exposure in workplace or risk of lung cancer in 42 cancer-free non-coal miners, 99 cancer-free coal miners and 51 coal miners with lung cancer in Taiyuan city in China. The results showed that plasma Hsp27 levels were increased in coal miners compared to non-coal miners (P...
2020-06-12 16:18:38浏览：1407
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Application of Fuzzy-PID Control System in Full-Mechanized Coal Face
The control system, which includes structure, the composition of software and hardware, the form of PID control system and its systematic closed-loop, was used in No.4236 full-mechanized coal face of Xinlongzhuang mine.The typical fuzzy PID control system structure was investigated, and a simplified fuzzy PID control system was taken the place of the complex three-dimension fuzzy controller. Based on the parameter relation between fuzzy controller and normal PID controller, a common method of parameter adjustment of PID controller was summed up and the computer simulation was realized. This system can overcome the problems of large delay, nonlinear, poor running environment and great load change in the full-mechanized coal face. The simulating investigation indicates that the designing method of fuzzy controller is simple and feasible....
2020-06-12 16:18:36浏览：1438
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Analysis of the Harmfulness of Water-Inrush from Coal Seam Floor Based on Seepage Instability Theory
A theory of seepage instability was used to estimate the harmfulness of water-inrush from a coal seam floor in a particular coal mine of the Mining Group, Xuzhou.Based on the stratum column chart in this coal mine, the distribution of stress in mining floors when the long-wall mining was respectively pushed along to 100 m and to 150 m was simulated by using the numerical software (RFPA2D).The permeability parameters of the coal seam floor are described given the relationship between permeability parameters.Strain and the water-inrush-indices were calculated.The water-inrush-index was 67.2% when the working face was pushed to 100 m, showing that water-inrush is possible and it was 1630% when the working face was pushed to 150 m, showing that water-inrush is quite probable.The results show that as long-wall mining is pushed along, the failure zone is enlarged, the strain increased, and fissures developed correspondingly, resulting in the formation of water-inrush channels.Accompanied by the failure of the strata, the permeability increased exponentially.In contrast, the non-Darcy flow β factor and the acceleration coefficient decreased exponentially, while the increase in the water-inrush-index was nearly exponential and the harmfulness of water-inrush in the coal mine increased accordingly....
2020-06-12 16:18:35浏览：1413
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Characteristics of stress distribution in floor strata and control of roadway stability under coal p
Given the difficulties encountered in roadway support under coal pillars, we studied the characteristics of stress distribution and their effect on roadway stability, using theoretical analysis and numerical simulation. The results show that, under a coal pillar, vertical stress in a floor stratum increases while horizontal stress decreases. We conclude that the increased difference between vertical and horizontal stress is an important reason for deformation of the surrounding rock and failures of roadways under coal pillars. Based on this, we propose control technologies of the surrounding rock of a roadway under a coal pillar, such as high strength and high pre-stressed bolt support, cable reinforcement support,single hydraulic prop with beam support and reinforcement by grouting of the surrounding rock, which have been successfully applied in a stability control project of a roadway under a coal pillar....
2020-06-12 16:18:32浏览：1433
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Pore pressure fluctuations of overlying aquifer during residual coal mining and water-soil stress co
Three test models and a simulation model were constructed based on the prevailing conditions of the Taiping coalmine in order to analyze pore pressure fluctuations of an overlying aquifer during residual coal mining. As well, the relation between pore pressure and soil stress was evaluated. The model tests show the vibrations of pore pressure and soil stress as a result of mining activities. The simulation model tells of the response characteristics of pore pressure after mining and its distribution in the sand aquifer. The comparative analysis reveals that pore pressure and soil stress vibration are activated by unexpected events occurring in mines, such as collapsing roofs. An increased pore pressure zone always lies above the wall in front or behind the working face of a mine. Both pore pressure and vertical stress result in increasing and decreasing processes during movements of the working face of a mine. The vibration of pore pressure always precedes soil stress in the same area and ends with a sharp decline. Changes in pore pressure of sand aquifer are limited to the area of stress changes. Obvious changes are largely located in a very small frame over the mining face....
2020-06-12 16:18:29浏览：1432
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A new technology for coal and gas control based on the in situ stress distribution and the roadway l
An auxiliary gas control technology is described that can reduce coal and gas outburst accidents when there is no existing protective coal seam and gas pre-draining is not effective.Numerical simulation methods were used to study the Stress distribution ahead of the roadway face for different in situ stresses.The results from the simulation can then provide a new gas control technology.The results show that a high stress concentration,high stresses,and high displacement gradients appear ahead of the roadway face when the maximum in situ stress is aligned perpendicular to the roadway axis.The risk of gas outburst is higher when the stresses decrease rapidly over distance and when the release of more energy occurs immediately after driving the roadway.The gas outburst risk is much smaller when the in situ stress is aligned parallel to the roadway axis.During design of the coal mine most of the coal roadways should be arranged to parallel the maximum in situ stress.This will decrease the outburst risk in general and may be considered a new gas outburst prevention method....
2020-06-12 16:18:28浏览：1431
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Nanobubble generation and its applications in froth flotation(part Ⅳ): mechanical cells and speciall
Coal is the world's most abundant fossil fuel.Coal froth flotation is a widely used cleaning process to separate coal from mineral impurities.Flotation of coarse coal particles,ultrafine coal particles and oxidized coal particles is well known to be difficult and complex.In this paper,the nanobubbles' effects on the flotation of the varying particle size,particle density and floatability coal samples were evaluated using a bank of pilot scale flotation cells,a laboratory scale and a pilot scale specially designed flotation column.The parameters evaluated during this study include the flow rate ratio between the nanobubble generator and the conventional size bubble generator,the superficial air velocity,collector dosage,frother concentration,flotation feed rate,feed solids concentration,feed particle size,and the superficial wash water flow rate,etc.The results show that the use of nanobubbles in a bank of mechanical cells flotation and column flotation increased the flotation recovery by 8%～27% at a given product grade.Nanobubbles increased the flotation rate constants of 600～355,355～180,180～75,and 75～0 microns size coal particles by 98.0%,98.4%,50.0% and 41.6%,respectively.The separation selectivity index was increased by up to 34%,depending on the flotation feed characteristics and the flotation conditions....
2020-06-12 16:18:28浏览：1412
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Computer controlled measurement of spontaneous combustion in coal stockpiles of the Western Lignite
The spontaneous combustion event in coal stockpiles is inevitable when appropriate environmental conditions are available.The objective of a computerized measurement system is to measure temperature changes existing in a coal stockpile.In order to achieve this intention, the electrical signal conversion of temperatures sensed by 20 temperature sensors placed in certain points inside the coal stockpile, the transfer of these electrical signals into computer media by using analogue-digital conversion unit after applying necessary filterization and upgrading processes and the record of these information into a database in particular time intervals are provided.Afterwards, the diagrams of these time-temperature data are plotted.With the help of these graphs, the competent company will be able to examine the behavior of coal stockpiles in terms of spontaneous combustion and take necessary precautions against self-combustion beforehand....
2020-06-12 16:18:27浏览：1406
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Effect of vanadium occurrence state on the choice of extracting vanadium technology from stone coal
The extraction technology of vanadium from stone coal by means of no-salt-roasting and dilute acid solution leaching treatment has the advantages of low pollution,low investment,as well as high vanadium leaching efficiency,which makes it the best technology for extendingapplication.In the present study,the effects of vanadium occurrence state in stone coal,roasting temperature and additive agent on the leaching efficiency of vanadium were studied.The results indicate that the effect of vanadium occurrence state on the extracting vanadium technology is obvious.If the vanadium component in stone coal existed in amorphous phase form,this type of stone coal can be treated by no-slat-roasting and dilute acid solution leaching technology; while the vanadium-bearing crystalline phase existed in stone coal,the roasting additive must be added to destroy this crystalline form so as to acquire high vanadium leaching rate....
2020-06-12 16:18:26浏览：1396
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Soft-strong supporting mechanism of gob-side entry retaining in deep coal seams threatened by rockbu
When gob-side entry retaining is implemented in deep coal seams threatened by rockburst, the cement-based supporting body beside roadway will bear greater roof pressure and strong impact load. Then the supporting body may easily deform and fail because of its low strength in the early stage. This paper established the roadside support mechanical model of gob-side entry retaining. Based on this model, we proposed and used the soft–strong supporting body as roadside support in the gob-side entry retaining. In the early stage of roof movement, the soft–strong supporting body has a better compress-ibility, which can not only relieve roof pressure and strong impact load, but also reduce the supporting resistance and prevent the supporting body from being crushed. In the later stage, with the increase of the strength of the supporting body, it can better support the overlying roof. The numerical simulation results and industrial test show that the soft–strong supporting body as roadside support can be better applied into the gob-side entry retaining in deep coal seams threatened by rockburst....
2020-06-12 16:18:23浏览：1435
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