Tiandi Science And Technology

Beijing, China

Tiandi Science And Technology

Beijing, China
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Tang L.,Tiandi Science And Technology
Zhongguo Kuangye Daxue Xuebao/Journal of China University of Mining and Technology | Year: 2015

The density of a gas-solid fluidized bed for dry coal beneficiation should be adjusted by the fine coal mass percentage. The distribution characteristics of 1.5-0.5 mm fine coal in fluidized beds containing wide-size-range medium solids were investigated in this paper. The experimental results show that the mixture of 1.5-0.9 mm coal and 0.3-0.06 mm magnetite powder is unsuitable to be used as medium solids in gas-solid fluidized bed. To avoid the negative effect on fludization performance, the mass percentage of 1.5-0.9 mm fine coal should be no more than 3.09%. 0.9-0.7 mm fine coal can be used as part of the medium solids, but the proportion should be controlled within 5.12%. 0.7-0.5 mm fine coal can be uniformly mixed with the magnetite powder as medium solids during dry beneficiation of coal. Therefore, magnetite powder less than 0.3 mm, which contains more than 80% of 0.3-0.06 mm particles, can be utilized as medium solids. Furthermore, it is reasonable to adjust the density of fluidized bed by changing the mass percentage of fine coal with particle size less than 1 mm. The optimization schemes for enhancing the uniformity of fine-coal distribution across the bed were proposed, which would provide a foundation for adjusting the density of the bed. © 2015, China University of Mining and Technology. All right reserved.


Zhang Y.,Tiandi Science And Technology | Zhang Y.,China Coal Research Institute | Li F.,China Coal Research Institute
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2011

Taking Wangpo mine as the experimental mining, by borehole flushing fluid leakage and drilling colour television system, the height of overburden failure caving and fissure development evolution are monitoring. And then, the digital analysis and similarity simulation experiment of fissure development evolution are carried out. The research results show as followings: (1) The overburden failure height of high tension fully mechanized caving mining Wangpo mining is from 94.00 m to 104.92 m. (2) The main distribution characteristic of rock fissure is that the evolution of fissure is mainly with the high angle even vertical to the rock strata; the fissure evolution amount is square increasing with the buried depth; and the fissure width is normal distribution approximately with the fissure amount. (3) The fissure cluster region focus on before and after the coal wall; and the fissure density distribution curves of overlying strata are high at both ends, low of the middle, such as saddle-shaped.


Hu B.,Tiandi Science And Technology
Advanced Materials Research | Year: 2014

In order to further improve the recovery ratio in strip mining, this paper makes use of the law of insufficiency and sufficiency in strata movement and buildings' additional stress release features, puts forward twice strip mining technology. The paper introduces the method and feasibility of twice strip mining. By analyzing karst cave collapse mechanism, the paper points out vertical cracks and horizontal layer separations are the direct causes of karst caves collapses and small strength mining each time can reduce karst cave collapse. The new technology has been applied in Pinghu Mine. It has totally extracted recoverable coal reserves under village buildings, effectively controlled strata deformation, and successfully avoided karst cave collapse within Yangkeng village. © (2014) Trans Tech Publications, Switzerland.


Xu G.,Tiandi Science And Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2010

From the production capacity, daily advancing rate, parameters, main equipment of the fully mechanized longwall coal mining face, stated the match technology development of the fully mechanized longwall coal mining in China. From the reliability, automation level, key component performance and others of the fully mechanized longwall mining face equipment in China, stated the gap with the overseas equipment and had an outlook on the development orientation of the fully mechanized longwall mining technology in China, which will take the high efficient integration production as the development orientation, take the safety, high efficiency, high mining rate and environmentally friendly as the target, realize the automation and information, improve reliability of the equipment, reduce the labor consumption and improve the production efficiency. The width of the coal mining face will be over 400 meters, the coal shearer will realize a face memory cutting and the hydraulic support will fellow the coal shearer automatically to push the conveyor forward. Based on the intelligent and visualization technology of the coal mining face, the gateway is central controlled with the surface remote control. The coal mining face in the medium seam realizes an annual production of 10 million tons. The research on the completed set equipment and technology of the high efficient mining in complicated and difficult mining seam shall be enhanced. The research and development shall be conducted on the completed technology and the equipment for the steep inclined seam and high inclined seam mining, the thin and ultra thin seam high efficient mining and the manless automation coal mining face.


Zhang S.-H.,Tiandi Science And Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2010

Reviewed the 4 stages of China coal shearer technology development. The 4 stages were including the starting stage, the import, copy, research and development combined stage, the self development and series mode development stage and the electric haulage coal shearer development stage. Stressed the key technology development of the coal shearer in the passed 40 years of the fully mechanized coal mining in China and had a technical comparison with the coal shearers made in domestic and overseas. Analyzed the differences between the advanced technologies of China and foreign countries and the differences were mainly in the product reliability, the technique, means, fault detection of the production and manufacturing, the communication transmission, the automation control, the basic theory study and other aspects. Pointed out that in the near future, China shall stress the development of the power pin rail type haulage system, the distributed electric control system based on the network and module, the modern design analysis technology based on the service life of the coal mining machinery products, the automation mining technology of the coal shearer and other coal shearer technology.


Wang G.-F.,Tiandi Science And Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2010

Based on the development course of the technical system of the China hydraulic powered support, from the type development and manufacturing of the hydraulic powered supports, the design theory and standard system of the hydraulic powered supports, the key material and control system technology of the hydraulic powered supports and the advanced manufacturing technology development of the hydraulic powered supports, introduced the development status of the hydraulic powered supports at home and abroad and the new type and update research and development achievements of the domestic thin seam powered support, medium seam powered support, high cutting height powered support, top coal caving powered support, high inclined seam powered support and special powered support. Analyzed the development tendency and orientation of the hydraulic powered support development at home and abroad, which would be continuously to improve the technical system of the hydraulic powered support, to develop the high advanced material and key original components, to innovate and develop the new type hydraulic powered supports and the performance automatic coupling type hydraulic powered support suitable for different seam conditions and the new mining methods.


Zheng S.-B.,Tiandi Science And Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2010

Based on the joint method of in-situ measurement and theoretical analysis, the 3D geostress field distribution and the optimal direction of roadway axis were studied for No.3 coal seam of east mine section in Sihe Mine of Jincheng Anthracite Mining Group. The type of geostress field in this section was defined to be σ HV belonging to the classical tectonic stress field. The relationship between the optimal direction of roadway axis and the direction of the maximum principal stress was analyzed in this type of geostress field. The research results indicate that the optimal direction of roadway axis is not parallel to the direction of the maximum principal stress, but has a certain angle to it. The angle dimension is determined by the ratio of the three principal stresses. In addition, the effect of tectonic stress on the stability of the roadway is smaller while the angle is not greater than 30°.


Pan J.-F.,China Coal Research Institute | Pan J.-F.,Tiandi Science And Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2011

According to the case and theoretical analysis, the concept of rock burst stat-up was brought forward, pointed out that rock burst occurred through three periods named rock burst start-up, energy transfer, rock burst emerged. Put the focus of rock burst prevention forward to the period of rock burst stat-up, a engineering structures model of roadway rock burst was established. The research results show that rock burst stat-up from the floor in whole coal roadway because of the high stress concentration in both side of roadway, and the floor only is the carrier of energy transfer and release, which show the location of rock burst occured. Further put forward the theory of rock burst stat-up, which point out that the intrinsic factor of rock burst stat-up is the excessive accumulation of static load in roadway near-field system, the exterior factor is dynamic load source from outside the system, and the energy criterion of rock burst stat-up is fixed on. Pointed out the possible area of rock burst start-up.


Gao F.,Simon Fraser University | Gao F.,Tiandi Science And Technology | Stead D.,Simon Fraser University | Coggan J.,Tiandi Science And Technology
Computers and Geotechnics | Year: 2014

The paper presents an innovative numerical approach to simulate progressive caving of strata above a longwall coal mining panel. A proposed Trigon logic is incorporated within UDEC to successfully capture the progressive caving of strata which is characterized by fracture generation and subsequent propagation. A new damage index, D, is proposed that can quantify regions of both compressive shear and tensile failure within the modelled longwall. Many features of progressive caving are reproduced in the model and found to fit reasonably well with field observations taken from a case study in the Ruhr coalfield. The modelling study reveals that compressive shear failure, rather than tensile failure, is the dominant failure mechanism in the caved strata above the mined-out area. The immediate roof beds act like beams and can collapse in beam bending when vertical stress is dominant or in beam shear fracture when horizontal stress is dominant. The proposed numerical approach can be used to guide the design of longwall panel layout and rock support mechanisms. © 2013 Elsevier Ltd.


Wang M.,Tiandi Science And Technology
Hangkong Cailiao Xuebao/Journal of Aeronautical Materials | Year: 2016

A new FeAlCrBSiNb cored wire was designed to prepare coating by high velocity arc spraying on 45 steel. Phase composition and microtructure of FeAlCrBSiNb coatings were characterized by SEM, XRD and TEM. The formation mechanism of the amorphous coating was discussed. Then the wear behavior and mechanical properties of the coating were investigated by ring-block tribometer, universal testing machine and microhardness tester. The results show that the coating consists of amorphous, α-Fe, (Fe, Cr), Fe3Al microcrystalline phase, and the volume fraction of amorphous phase is 91.3%. The coating has very compact structure with low porosity of 2%.The average microhardness of the coating can reach approximately 850 HV0.1, which is 4 times of that of 45 steel. Wear resistance of the coating is excellent, which is 5 times of that of 45 steel under dry friction condition. The main wear mechanism is brittle flaking-off. © 2016, Chinese Journal of Aeronautics. All right reserved.

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