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0 Preface
Shannan Yunnan Wen Wen River tungsten mine is one of Wenshan Malipo Zijin Tungsten Industry Group Co., Ltd. is the focus of mining enterprises, divided into mining in the south section of seedling, Mau, at present, mainly ore mining seedling south east and west . The rock joints and fissures in the Nanwenhe tungsten deposit are not developed, and the stability is good. The engineering geological and hydrogeological conditions of the mining area are relatively simple.
At present, there are the following problems in the underground mining of the Nanwenhe tungsten mine: there are many old goafs in the underground. With the continuous mining, the exposed area of ​​the underground goaf is getting larger and larger, and the safety hazard is larger. Some of the pillars have already occurred. Rupture; the mined-out area left by underground mining is not closed in time; after years of civil mining and piracy, and the irregularity of the pillars, the order of recovery is chaotic, which is not conducive to mine management and safe production; The underground pressure monitoring system has never been established in the underground mining of Hedong tungsten mine; the geometrical parameters of the retained pillars of the Nanwenhe tungsten mine are selected by experience and have not been verified by the stability of the pillar [1].
At present, Nanwenhe tungsten mining faces a series of ground pressure control problems, and it is urgent to solve the problem of ground pressure disasters. Therefore, it is considered to establish a ground pressure monitoring network suitable for the characteristics of the mine in the Nanwenhe tungsten mine, establish a long-term and effective ground pressure monitoring and management system, and realize the ground pressure monitoring and early warning of the Nanwenhe tungsten mine through real-time ground pressure monitoring. To guide mine safety production.
1 Status of the mining area of ​​Nanwenhe tungsten mine and the phenomenon of ground pressure activity
The Nanwenhe tungsten ore body is a gently inclined thin ore body and is mined by the room and pillar method. Each stope is divided into 80m×80m in the mining area, and 4m×4m or Φ4m pillars are reserved in the stope with a span of 8～12m.
From the field situation, the parameters of the stope can basically meet the stability requirements of the roof. However, some of the pillars between the 2-6 exploration lines of the mine section have ground pressure and cracking, which indicates that the ground pressure is obvious in this area, which will affect the safe mining of the mining area in the future [1] ].
At present, the area of ​​the goaf that has been formed underground is 77×104 m2, and the volume of the goaf is about 200×104 m3, and the mining in the future will increase at a speed of about 30×104 m3/a.
Due to the large size of the goaf of the Nanwenhe tungsten mine, it will inevitably involve the safety and stability of the goaf and the problem of roof control. In order to eliminate or reduce the damage of the goaf to the safe mining of mines, it is necessary to conduct a detailed investigation of the goaf existing in the Nanwenhe tungsten mine and the stability and safe mining technology of the goaf of the Nanwenhe tungsten mine. The conditions are demonstrated and analyzed to determine the stability status of the existing mined-out pillars, so as to define the hazard range of the goaf and provide a basis for the mine goaf treatment and the ground pressure monitoring of the goaf. Provide technical support for the safe and orderly production of mines.
2 Nanwenhe tungsten mine ground pressure monitoring key area
In the early stage, detailed investigations were carried out on the mining status and geomorphic characteristics of the Nanwenhe tungsten deposit, as well as the indoor test of the Nanwenhe tungsten ore rock mass and the calculation and analysis of the retained pillar stability in the goaf. The safety factor of the retained pillars is verified and calculated. According to the calculation results, the dangerous area of ​​the ground pressure activity of the mine is preliminarily determined, and the ground pressure monitoring area of ​​the Nanwenhe tungsten deposit is determined after comprehensive consideration of the actual situation of the mining. Among them, the key areas of ground pressure monitoring are: No. 7 along the line 4 east, 4 lines main transport lane east, 1-5 line 10 along the north and south, 3 line 8 along the north; general monitoring area: 2 line 8 No. along the north and south of the vein and the old tungsten mining area. The ground pressure monitoring points are arranged in the point columns in the stope or goaf area of ​​the above area and between the top and bottom floors of the goaf [1].
3 Design of stability monitoring scheme for goaf
3.1 Monitoring method and scheme of ground pressure in Nanwenhe tungsten mine
Ground pressure monitoring in hard rock metal mines generally uses multi-channel acoustic emission/microseismic monitoring (AE/MS), stress monitoring and displacement monitoring. The rock strength of Nanwenhe tungsten mine is over 90 MPa, and the rock mass is high, which is a hard rock. mine. In view of the actual situation of the mining area, it is proposed to use acoustic emission monitoring as the main, combined with monitoring methods such as stress monitoring and displacement monitoring, to establish an all-round, multi-level ground pressure monitoring network, using fiber optic cables from the underground monitoring chamber to the surface monitoring office. Establish a real-time network system for ground pressure monitoring of surface network, and realize the synchronization of various ground pressure monitoring data in the Nanwenhe tungsten mine with the ground monitoring room data [2-4].
By understanding the basic principles and applications of multi-channel acoustic emission monitoring, micro-seismic monitoring, single-channel acoustic emission monitoring, and stress monitoring and displacement monitoring systems, it is determined that the ground pressure monitoring program of the Nanwenhe tungsten mine is carried out from the following three monitoring schemes. select.
(1) Option 1: Microseismic monitoring + stress monitoring + displacement monitoring system.
(2) Option 2: Multi-channel acoustic emission monitoring + stress monitoring + displacement monitoring system.
(3) Option 3: Multi-channel acoustic emission monitoring + single-channel acoustic emission monitoring + stress monitoring system + displacement monitoring system.
The advantages of the scheme 1 are: the informationization, integration and intelligence of the microseismic monitoring system are relatively high, and the operation interface of the system is beautiful; the disadvantages of the microseismic monitoring system are high price, high maintenance cost, and the system and software are all in English. The advantages of the technicians are high, and the operation is inconvenient; the advantage of the scheme 2 is: Compared with the scheme 1, the multi-channel acoustic emission system is cheap, the service after installation is more convenient, and the basic function of the system is monitored. It can also meet the requirements of ground pressure monitoring. The disadvantage is that the operation interface of the multi-channel acoustic emission system is not as beautiful as the operation interface of the micro-seismic monitoring system of the scheme 1; the advantage of the scheme 3 is: comparison scheme 1, the price of the multi-channel acoustic emission system It is cheaper and more convenient to service. It can also meet the requirements of ground pressure monitoring, including single-channel acoustic emission monitoring system. Therefore, it has wide coverage of ground pressure monitoring. Single channel and multi-channel complement each other and perfect Nanwen River. The disadvantage of the ground pressure monitoring network in the mining area is that the operation interface of the multi-channel acoustic emission monitoring system is not as beautiful as the operation interface of the micro-seismic monitoring system of the scheme 1. .
Through detailed comparison and analysis of the reliability and economic technology indicators of the above three sets of ground pressure monitoring schemes, consider selecting the technical equipment that is currently mature in domestic application, including: acoustic emission monitoring system (single channel acoustic emission monitoring, multi-channel sound) Comprehensive ground pressure monitoring means such as launch monitoring, rock mass stress monitoring system and rock mass displacement monitoring system, establish a perfect ground pressure monitoring network system for the mine. Therefore, it is finally determined that the ground pressure monitoring scheme of the Nanwenhe tungsten mine is the scheme 3 [1] in the above scheme, namely the multi-channel acoustic emission monitoring system + the single-channel acoustic emission monitoring system + the stress monitoring system + the displacement monitoring system.
3.2 Selection of ground pressure monitoring equipment for Nanwenhe tungsten mine
According to the use of the instrument in the actual mine and the application effect, after comprehensive comparison, it is determined that the following types of ground pressure monitoring instruments are used [4]:
(1) DYF-2 single-channel acoustic emission meter produced by Changsha Mining Research Institute Co., Ltd.;
(2) STL-12 multi-channel acoustic emission positioning system produced by Changsha Mining Research Institute Co., Ltd., or AEM rock sound emission monitoring and positioning system produced by Changsha Jihua Mining Technology Co., Ltd.;
(3) ZLGH-20 drilling stress gauge and testing equipment produced by Shandong University of Science and Technology Losyel Sensor Cable Co., Ltd.;
(4) WYGH-II displacement monitor produced by Shandong University of Science and Technology Losyel Sensor Cable Co., Ltd.
3.3 Design of ground pressure monitoring point in Nanwenhe tungsten mine
3.3.1 Multi-channel acoustic emission monitoring point design
The multi-channel acoustic emission monitoring points of the Nanwenhe tungsten mine are arranged in the stope and mining along the north and north of the No. 7 line along the 4th line of the east and fourth lines of the line 4, along the north and south of the line, and along the north line of the 3rd line. In the point column of the empty area, although the B area is ready to be closed, in order to accurately understand the changes of the pillars and surrounding rock mass in the closed area [3], three multi-channel monitoring points are arranged in this area.
3.3.2 Single channel acoustic emission monitoring point design
The single-channel acoustic emission monitoring point of the Nanwenhe tungsten mine is designed to monitor the stability of the surrounding rock and pillar of the Nanwenhe mining area in combination with multi-channel acoustic emission monitoring points and stress monitoring points in the stope and mined-out point columns. A single-channel acoustic emission monitoring point is arranged in the point column of the ground pressure active area, and the number of single-channel acoustic emission monitoring points can be appropriately increased according to the design principle according to the actual situation on site.
3.3.3 Stress monitoring point design
The stress monitoring points of the Nanwenhe tungsten deposit are mainly designed along the north and the fourth line of the No. 7 line along the 4th line, the main transport lane east, the 1-5 line 10 along the north and south, and the third line along the 8th line; the general monitoring area is: 2 Line 8 along the north and south of the vein and the gob of the old tungsten industry goaf, mainly to monitor the stress transfer during the mining process, that is, the stress transfer distance, the pressure change in the monitoring point column, and Other monitoring methods jointly monitor the stress state of the rock mass around the goaf of the Nanwenhe tungsten mine, and monitor and analyze its stability in real time.
4 Conclusion
This paper summarizes the basic characteristics of the goaf in the Nanwenhe tungsten ore mining area, analyzes the ground pressure characteristics and the law of ground pressure activity of the mine, and studies and proposes a ground pressure monitoring method suitable for the characteristics of the Nanwenhe tungsten deposit. The key areas and general areas of the ground pressure monitoring of the mine were identified.
From the aspects of monitoring instrument price, function and after-sales service, comprehensive consideration and detailed comparison, the ground pressure monitoring system suitable for Nanwenhe tungsten mine is selected, namely: multi-channel acoustic emission monitoring system + single-channel acoustic emission monitoring system + rock The body stress monitoring system + displacement monitoring system system, and the optimization design of the ground pressure monitoring point in the Nanwenhe tungsten ore mining area, designed the ground pressure monitoring network of the Nanwenhe tungsten mine. The establishment of the ground pressure monitoring network can realize real-time monitoring of all-weather ground pressure in the Nanwenhe tungsten mine, which can effectively guide the safe production of the mine.
references:
[1] Changsha Mining Research Institute Co., Ltd. Research on ground pressure monitoring and early warning technology in goaf of Nanwenhe tungsten mine [R]. Changsha: Changsha Mining Research Institute Co., Ltd., 2014.
[2] Tao Xuefen, Li Aibing, Zhang Guang, et al. Design of stability monitoring scheme for goaf in a mine in Northwest China [J]. Modern mining. 2010(1): 80-82.
[3] Liu Guoqing. Micro-seismic monitoring system for rock engineering disaster based on acoustic emission [J]. Mining Technology, 2005, 5(1): 30-31.
[4] Yin Yanbo. Nonlinear dynamic analysis of rock instability and ground pressure disaster [D]. Changsha: Changsha Mining Research Institute Co., Ltd., 2006.
Yin Yanbo, School of Resources and Safety Engineering, Central South University, Changsha 410083, China; Changsha Mine Research Institute Co., Ltd., Changsha 410012, China;
Source: Mining Technology: 2016, 16(2);
Copyright:
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