Time filter

Source Type

Liu K.,China Coal Technology and Engineering Co.
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2017

The mechanical properties of raw coal specimens containing gas from the B10 seam of -780 m elevation in Huainan coal mine were studied under the conventional high stress triaxial compression by using the modified adsorption-penetration-mechanical coupling test system. The deviatoric stress-axial strain curves of the raw coal containing gas have the stages of elastic deformation, yielding, post-peak brittle failure or strain softening. The elastic period shows the fluctuation associated with strain-softening and strain-hardening. The post peak brittle failure feature is apparent. Under the same initial gas pressure, with the increase of the initial effective confining pressure, the trend of transition between the brittle and ductile is weak. Increasing the initial gas pressure can result in more significant brittle failure if the initial effective confining pressure is kept constant. The deviatoric stress-lateral strain curve has the linear elastic stage which is very smooth. The deviatoric stress-volume strain curve of raw coal containing gas shows dilation under the low effective confining pressure in the pre-peak region. With the increase of the effective confining pressure, the volume dilation delayed. The peak strength increases linearly with increase in confining pressure or gas pressure. The common failure mode for the coal specimens is shear failure and the cohesion and friction angle are 14.02 MPa and 25.93°, respectively. © 2017, Science Press. All right reserved.

Wang J.-H.,China Coal Technology and Engineering Co.
Meitan Xuebao/Journal of the China Coal Society | Year: 2013

Fully-mechanized top coal caving with large mining height is the main mining method for extra-thick coal seam.However, as the hight of coal cutting and coal caving increases, prominent problems such as severe mine pressurebehaviour, severe rib spalling in working face, low top coal recovery rate and high gas emission rate and so on emerge.Based on the analysis of the development history of the fully-mechanized top coal caving in China, taking the working face 8105 at Tashan Coal Mine as the engineering background, authors studied the movement characteristics of the top coal and roof at the fully-mechanized top coal caving face with large mining height in the 14-20 m extra-thick coal seam, successfully developed key technologies such as the comprehensive prevention and control technology for rib spalling at the fully-mechanized top coal caving face with large mining height, high-efficient coal caving technology with high recovery rate and safety guarantee technology for mining under the condition of "low gas occurrence, high gas emission", etc. The underground test showed that the recovery rate at the fully-mechanized top coal caving face with large mining height 8105 at Tashan Coal Mine reaches 88.9% which is 5.9% higher than that at working face 8104, the average operating rate of the equipment at the working face reach 92.1%, and the raw coal produced at the face in 2011 reach 10.849 Mt, which achiev the objective of 10 Mt coal produced at the fully-mechanized top coal caving face with large mining height using domestic equipment in a year.

Wang G.-F.,China Coal Technology and Engineering Co.
Journal of Coal Science and Engineering | Year: 2013

The paper introduced complete sets of automatic equipment and technology used in thin seam coal face, and proposed the comprehensive mechanization and automation of safe and high efficiency mining models based on the thin seam drum shearer. The key technology of short length and high power thin seam drum shearer, and new type roof support with big extension ratio and plate canopy were introduced. The new research achievement on automatic control system of complete sets of equipment for the thin seam coal, which composed of electronic-hydraulic system, compact thin seam roof supports, high effective shearer with intelligent control system, and characterized by automatical follow-up and remote control technology, was described in this paper. © 2013 The Editorial Office of Journal of Coal Science and Engineering (China) and Springer-Verlag Berlin Heidelberg.

Wang J.-H.,China Coal Technology and Engineering Co.
Meitan Xuebao/Journal of the China Coal Society | Year: 2012

Taking a tailgate with coal seam as roof in Tashan Coal Mine in Datong mining district for example, the numerical simulation of stress and deformation characteristics in the rock surrounding the tailgate was studied, with different thickness of roof coal, different tailgate locations, different height-width ratios, different in-situ stress and different pretension of bolts and cables through finite difference numerical software FLAC 3D. The results show that as the thickness of roof coal increases, the stress concentration area enlarges while the stress decreases within the roof coal of less than 10 meters; the distribution of stress concentration area in the coal pillars caused by the tailgate driving and adjacent longwall face mining is in the shape of "triangle"; with the same tailgate height, as the tailgate width increases, the stress concentration in the roof coal increases while the stress in the floor decreases; the higher the strength of coal and rock is, the higher the surrounding rock stress is; the bolt and cable pretension should form an effective compression stress zone which is supposed to overlap in anchorage range in surrounding rocks. The underground tests showed that the high strength and high pretension bolt and cable can effectively control the deformation of the surrounding rocks, provide an effective approach to support the gateroads with coal seam as roof.

Zhou R.-L.,China Coal Technology and Engineering Co.
Meitan Xuebao/Journal of the China Coal Society | Year: 2012

Aimed to solve the problems involving low level of automation and difficulties in guaranteeing effluent quality existing in the process of purification treatment of mine water, the automatic monitoring system was developed to suit for the technology for purification treatment of mine water. The system mainly consists of automatic dosing, automatic sludge discharge, process monitoring and remote network monitoring subsystems. Based on the simulation experiments, the mathematical models were set up including optimal dosage, sludge discharge quantity and inflow turbidity. The subsystems of automatic dosing and automatic sludge discharge were achieved by online detecting sensors, PLC, transducers, dosing pump and electrically operated valves. The subsystem of process monitoring was accomplished by PLC, industrial personal computer, imitation screen and power equipment. And the subsystem of remote network monitoring was achieved by monitoring host, digital exchangers, communication modules, industrial optical fiber Ethernet and monitoring platform established by configuration software. The system can reduce water treatment cost, improve management level and work efficiency under the conditions of ensuring the treatment water flow and the effluent quality.

Wang H.,China Coal Technology and Engineering Co.
Procedia Engineering | Year: 2011

The emergency rescue for coal mine disaster is very important to mine security. The environments of coal mine is complicated and dangerous. In order to ensure the self-security of rescuer, minimizing the accident losses, the emergency rescue life sign monitoring sensor based on Fiber Bragg Grating(FBG) and three-axis acceleration sensor are studied in this paper. Firstly, the structure of the emergency rescue system for coal mine disaster is built. Then the life sign monitoring sensor of emergency rescue system for coal mine disaster is studied in detail, includes the detection model of body temperature, the heart rate detection technology for rescue staff, and the detection method of rescue staff posture. Finally, the experiment is made to test the effect of the sensor. The results show that the sensor sensitivity to rescue staff life sign is higher, and it can satisfies the needs of the emergency rescue for coal mine disaster. © 2011 Published by Elsevier Ltd.

Wang H.,China Coal Technology and Engineering Co.
Meitan Xuebao/Journal of the China Coal Society | Year: 2010

Reviewed the development course of China fully mechanized mine roadway heading in the passed 40 years and summarized the present status of the fully mechanized coal mine roadway heading technology and equipment in China. Summarized the problems existed in the fully mechanized mine roadway heading technology and equipment in China underground mines and pointed out that the factors mainly of the time to set up the support, the dust control efficiency at the heading face, the component reliability and the automatic control technology would restrict the mine roadway heading speed. In comparison with the overseas, analyzed the gap of the cutting technology, the component reliability, automatic control technology, the dust control system and the system matching technology of the domestic roadheader. Finally provided the development orientation of the boom type roadheader and the fully mechanized mine roadway heading technology in China, it is improving the flexibility of the completed machine and expanding the application scope, having the fundamental technical research, improving the application performances of the components and developing the matching technology of the fully mechanized mine roadway heading system.

Zhang J.,China Coal Technology and Engineering Co.
Conference Proceedings - 2012 IEEE 7th International Power Electronics and Motion Control Conference - ECCE Asia, IPEMC 2012 | Year: 2012

Shunt Active Power Filter is an ideal device that could manage the harmonic compensation in an adjustable and dynamic manner. This article reviews the basic principle of shunt active power filter, along with the current tracking circuit based on the instantaneous reactive power theory and the main circuit performing as an inverter with PWM hysteresis control. A comprehensive control method is analyzed and a harmonic compensation simulation is conducted, the result of which verifies the harmonic detection algorithm is well-proposed and the power quality of the grid is overall-enhanced. © 2012 IEEE.

Ji Q.,China Coal Technology and Engineering Co.
Procedia Engineering | Year: 2014

Hole accidents during drilling and borehole collapse during extracting are bottlenecks restricting gas drainage efficiency in soft outburst-prone coal seams in China. The auger-air combined drilling technique and sieve tube mounting method are an alternative solution to these technology bottlenecks. The auger-air drilling technique combines the advantages of "dry style" auger drilling and air drilling. Specially designed blade in drill rod can stir up large particles of coal so that large particles can be brought to ground smoothly using compressed air and is efficient to prevent borehole accidents. After drilling is completed, the sieve tube is tripped in through the inner hole of drilling pipes, and then lifting up drilling pipes, the tube sieve will provide a complete tunnel for gas extraction. Field application proves that with proper drilling parameter selection and appropriate tube install control, it is more promising to double drilling depth and raise gas drainage efficiency. © 2014 Published by Elsevier Ltd.

China Coal Technology and Engineering Co. | Date: 2015-07-31

An infrared detection device can be used to detect coal mine polar gas. The detection device can include a central processor and a gas pool assembly having a moveable optical window. The moveable optical window can include a stationary pool body and a moveable pool body inserted into the stationary pool body.

Loading China Coal Technology and Engineering Co. collaborators
Loading China Coal Technology and Engineering Co. collaborators