1、英文原文 Study on mining the protective seam with the manless working facein coal and gas outburst mines Fang Xin-qiua,b, Zhao Jun-jiea,b, He Jiea,b, aSchool of Mines, China University of Mining & Technology, Xuzhou 221116, China bState Key Laboratory of Coal Resources and Safety Mine, Xuzhou 221008, Ch
2、ina Abstract: In order to solve the problems of backward equipments, low recovery, security issues, high mortality in the coal industry, thetechnology of manlessworking face in mine which combined the traditional mining process with the automatic technology isproposed based on the scientized mining,
3、 meanwhile, the idea of exploiting the protective seam in the coal seam group of the coaland gas outburst mines with manless working face technology is also proposed so as to liberate other high gas coal seams. Then,making the third coal seam in Shaqu coal mine which is a coal and gas outburst mine
4、as the protective seam was being exploitedand carried out the designs which included roadway, equipments selection and mining process. Finally, based on the theoreticalanalysis and numerical simulation, the gas extraction arrangements is designed, which provides the scientific basis and methodfor in
5、dustrial experiment of the third coal seam. Key words: scientized mining； coal seam group； protective seam； manless working face； gas extraction 1. Introduction The scientized mining means mining the coal with the highest efficiency on the precondition of safety andenvironment friendly 1. Chinas coa
6、l output is very big, the advanced mining machines must be used in order toadapt to the construction of modern mine, furthermore, the manless working face should also be used in somedifficult conditions such as thin coal seam or coal and gas outburst seam. Although the mining technology developsrapi
7、dly, the overall level is still relatively backward. In order to solve this problem, change the present situation andkeep the sustainable development of coal resources 2, the author proposes that the protective seam ismined withthe manless working face in the coal and gas outburst mines. Then other
8、high-gas coal seams can be liberated andthe gas concentration can also be decreased, so there will be a safecondition for mining. Finally, the safe and highefficient green mining will be achieved 3. 2. Mining the protective seam in high outburst mines The coal seam group is one character of the high
9、 gas mining area in china and the permeability of coal seam isvery low 4. Therefore, gas is the primary factor which prevents this kind of mines from safety and high efficiency.The protective seam mining is widely used in these high outburst mines in China so as to solve this problem. Inaddition, th
10、is is the most scientific method to prevent the regional gas outburst under the condition of mining thecoal seam group in high outburst mines 5, 6. When there is a coal seam group in the gas outburst mine, the no-outburst seam or little-outburst seam will befirstly exploited, and this kind of coal s
11、eam is called the protective seam. The original equilibrium state of stress willbe broken after the protective seam is exploited. Besides, with the development of roof and floor, the strata stresswill be redistributed. The roof strata can be divided into caving zone, fractured zone, and bending zone
12、 7, the floorstrata will generate floor heave and fractures 8. The fractures contain bedding joint and cross-fracture, the degree ofthe fracture development of the floor is in inverse proportion to the spacing of layers. The methods of gas extractioncan be classified as short distance, medium distan
13、ce and long distance through the relative spacing of layers which isbased on the concrete geological conditions of the coal mines 9, which provides a theoretical guidance to the gascontrol of coal seamgroup. The practice of mining the protective seam shows that the gas permeability of the upper outb
14、urst-relieved seamincreases 1000-3000 times, while that of the lower outburst-relieved seam increases about 1000 times. This providesa good chance for gas extraction. So the effect of the increased gas permeability should be fully utilized to extractthe gas by arranging kinds of drillings or roadway
15、s which not only ensures the safety of mines but also guaranteesthe extracted green and efficient gas energy for industry. Then the simultaneous extraction of coal and gas can berealized. The concrete methods are as follows: (1)Extracting the gas by ground surface drilling. This method is applied su
16、ccessfully in America 10, besides,Huainan, Huaibei, and Tiefa mining bureaus also made some tests or applications 11. Although they have got someeffect, the stability of the drillings are not very well so that they are broken before the expected life for the differentgeological conditions between Ch
17、ina andAmerica and the influence of the movement of the overlying strata. (2) Arranging some drillings and roadways in the coal seam or strata to extract the gas which is the main methodwidely used in solving the gas outburst problem. 3. Analysis of the feasibility and application in manless working
18、 face 3.1. Analysis of the feasibility The modern manless working face is proposed with the principle of scientized mining and comprehensiveutilization of coal resources 12. Based on the concrete conditions of China, we analyze the feasibility of manlessworking face: The gas emission of the thick an
19、d medium-thickness coal seam is more thinner than coal seam, so the thin coalseam is the first choice as protective seam. At present, although the mining degree of chanization and automationinthick and medium-thickness coal seam is relatively high, but in thin coal seam is relatively backward. Blast
20、ingmining is the main method of mining the thin coal seam, on the one hand, the mining production rate is low and thepartial coal resource is lost 13. On the other hand, the working environment is bad and the labor intensity is big.Considering these unfavorable factors, many coal mines give up explo
21、iting the thin coal seams. This action not onlywastes the coal resources seriously but also shortens the service life of the mines, meanwhile, it also restricts thedevelopment of the protective seam in the coal seam group of the coal and gas outburst mines. So the urgent affair inmining field is to
22、develop the high yield and high efficiency mining technology. Based on the system model of the manless working face, we make some integrated innovations on the moderntechnology and analyze the needed technology of every subsystem such as self-positioning and automatic navigation technology of the sh
23、earer, automatic vertical steering technology of the shearer, automatic recognition technologybetween coal and strata, electro-hydraulic control technology of the hydraulic support, automatic traction technologyof the scraper conveyor, two-way communication technology of high-speed in the undergroun
24、d, component basedcoalmine software as well as the model technology, database technology and multi-sensor technology. After being combined with these technologies, the manless working face technology can greatly improve themining rate and promote the security. Coal is the main energy resource in Chi
25、na, the healthy development of the coal industry is related to the energysecurity and economic sustainable development of China. The coal is non-renewable resource and the service life ofthe mine is certain. If the thin coal seam can be exploited through the existing production system, the recoverab
26、lereserves will be increased, and then the economic benefit will also be increased. At present, gas explosion has the highest proportion in all kinds of the coal mine accidents in China. There were182 coal mine accidents in 2008, the death toll was 778. So the preventing of gas accidents shoulders h
27、eavyresponsibilities. 3.2. Application Based on the scientific mining, exploiting the protective seam with manless working face is proposed combinedwith these analyses in coal seam group of the coal and gas outburst mines. After the gas in the coal seam group isreleased, it can be extracted by the r
28、easonable drillings. It is a win-win method, not only will the frequent gasoverrun, frequent gas accidents and the limitation of scale be solved, but also the problems of great difficulty inmining and low mining rate. Furthermore, the green mining of coal resources can be realized by simultaneous ex
29、traction of coal and gas. 4. Example of mining designs in manless working face 4.1. Condition of text area The Shaqu coal mine of the HUAJIN coking-coal company is a coal and gas outburst mine. The absolute outflowof gas is 344.43 m3/min and the relative outflow of gas is 61.8 m3/t. It is a short distance coal seam group and theminable seams are the second, third, forth and fifth coal seam (Fig.1).
