Development and prospect of safety technology in open-pit coal mines

After 1958, the state vigorously developed open-pit coal mining and began to build large-scale open-pit coal mines such as Pingshuo, Yuanbaoshan and Huolinhe. In order to adapt to the development of open-pit coal mining, the state decided to strengthen the research power of open-pit coal mining technology. 1965, the number of researchers increased to nearly 100. 1985 Fushun Branch of the General Research Institute of Coal Science established the Open-pit Coal Mine Safety Research Institute, and invested in and equipped laboratories such as slope rock mechanics, slope rock deformation monitoring and instruments, wheel bucket excavation and crushing mechanism, blasting vibration test, mining equipment performance test and computer information center.

In the past 47 years, the Institute of Open-pit Mining Safety has done a lot of research work in mining technology, mining equipment upgrading, blasting technology and equipment, slope stability and slope deformation monitoring technology, application of computer technology in open-pit mines, open-pit production monitoring technology, geological disasters and environmental assessment. * * * Completed more than 50 scientific research projects/KLOC-0, which provided reliable technical support for safe and efficient production in mines and contributed to the development of open-pit mining technology in China.

Especially, since 198 1, * * many projects have been completed10, which is 2.7 times of the previous 24 years, among which 32 achievements have won national, provincial and ministerial scientific and technological progress awards.

1 Research on mining technology, equipment, blasting technology and equipment

1. 1 mining technology

In the 1950s, the Institute of Open-pit Mine Safety successively completed the technical transformation scheme design of Fushun West Open-pit Mine, the research on the development mode and mining method of Haizhou Open-pit Mine, and the research on open-pit hydraulic mechanized coal mining.

1963- 1965, together with China university of mining and Shenyang coal mine design institute, surveyed 3 1 mines in four western provinces, planned 17 open-pit coal mines, and determined the technical development direction, mining methods and technology, which laid the foundation for the construction and development of open-pit coal mines in China in the 1980s.

In the mid-1960s, the mining technology in Pingshuo mining area was studied, and the development and mining scheme with an annual output of 500 ~100000 tons was put forward. The scheme includes continuous technology, railway transportation technology, bucket shovel, internal dumping and other combined technologies. The mining technology of super-large open-pit coal mine was studied for the first time in China, and the technical level reached the world level at that time. In order to cooperate with the development and construction of five open-pit coal mines, it has undertaken research on coal cutting resistance testing technology, groundwater drainage method in Yuanbaoshan open-pit coal mine, and anti-freezing technology to prevent peeling objects from sticking to cars in cold areas in the north. The field test of anti-sticking truck and the low temperature test of cold-resistant conveyor belt in Fushun West Open-pit Mine are the first time in China, and the results have been applied to the field and achieved good results.

In the 1980s, facing the difficulties of deep mining and deepening in the old open pit mine, he participated in the research of technical transformation. In particular, he participated in the technical transformation design of Fushun West Open-pit Mine for many times, and finally put forward the design scheme of upper railway transportation, combined transportation of deep trucks and belt conveyors, and mining in the distribution area of internal dumping. In order to cooperate with the implementation of this plan, the plan of strengthening the exploitation in the western region and realizing the internal discharge in the western region in advance was studied. The scheme has been implemented for many years and achieved good economic benefits.

1.2 open-pit mining equipment technology

1957 completed 120B study on improving the external characteristics of the electric shovel generator, which improved the working efficiency of the electric shovel by 5%~ 10% and reduced electrical and mechanical failures. "Research on SCR pulse speed regulation of 12t overhead electric locomotive for open pit mine" greatly reduces the locomotive failure rate and saves electricity by about 12%.

Q 2-M64 DTH drilling rig was developed after 1960s. The drilling rig can also drill inclined holes of 0~30 degrees; LH-200 rotary drilling rig is developed for medium-hard rocks. This kind of drilling rig can use cutting, roller cone, DTH and other drilling tools, and its efficiency is 3~5 times that of impact drilling. ZX- 150 rotary drilling rig was jointly developed with Jilin Heavy Machinery Factory. The displacement efficiency of KY- 150 roller drilling rig developed in 1986 reaches 7 1.5m and 178m, which is 2.54 times that of DTH drilling rig and 6.9 times that of impact drilling rig. The developed QZ3- 150 three-wing rotary drilling bit has the same service life as the American three-wing bit, reaching 2500m, and the price is only 42% of that of the American bit, which has replaced the import and has been used in Huolinhe open pit mine for a long time.

Together with Hangzhou Heavy Machinery, Shanghai Belt Transportation Machinery Factory and Fushun Excavation Machinery Factory, we undertook the development and test of the first set of continuous process equipment in China. Including wheel bucket excavator, belt conveyor, PS- 1000 dump truck, YG- 15 belt shifter, YR- 1 combined belt joint vulcanizer, ending the history that China could not produce continuous process equipment. In 1980s, Hangzhong and Tiangong Institute developed the first medium-sized wheel bucket excavator in China. The Institute of Open-pit Mining Safety participated in all industrial tests and performance tests, completed the mechanical performance measurement and production capacity assessment of complete sets of equipment, and initiated the performance test of mining equipment.

Wu Baoshan, Zhungeer and other large open-pit coal mines have partially adopted the wheel bucket belt continuous process, and imported large wheel bucket excavators from abroad. In order to cooperate with the design and equipment acceptance task of wheel bucket excavators in these units, the cutting resistance of coal and rock, the cutting and crushing mechanism of wheel bucket excavators, the design theory of wheel bucket working mechanism, the cutting force of wheel bucket excavation and the mechanical performance test are also studied.

Through the research and measurement of coal and rock cutting resistance in Yuanbaoshan, Fushun, Xiaolongtan, Zhaotong, Huolinhe, Zhungeer and Yimin open-pit mines, the theory of coal and rock cutting resistance and the measurement method of wheel bucket excavator in China are put forward, which fills the gap in this field in China and reaches the international level. Its achievement won the second prize of scientific and technological progress of the Ministry of Coal Industry. Using the above theory and testing technology, the mechanical performance test and production capacity evaluation of continuous process system in Zhungeer and Yuanbaoshan open-pit mines are completed, which provides guarantee for imported equipment in mines.

During this period, the Institute of Open-pit Mining Safety built the world's largest experimental device for bucket wheel excavators, with a bucket wheel diameter of 0.95 meters ... Through this device, the cutting resistance of different lithology and the determination of excavator cutting force can be simulated, and the reasonable working parameters of bucket wheel excavators can be studied. Such as: the stress state of bucket teeth, the shape of bucket teeth, the arrangement of bucket teeth, cutting speed, rotating speed, the size of planer, the wear resistance of bucket teeth materials, etc. The service life of the developed single bucket electric bucket tooth is 2.5~3.0 times that of the common bucket tooth.

1.3 blasting technology and equipment

In order to solve the blasting quality problem of high-stage mining in Fushun West Open-pit Mine, the high-stage blasting technology was studied at 1956.

During the period of 1972- 1973, the ballast blasting method was adopted in Haizhou open-pit mine. 1985 "Study on Blasting Method for Increasing Lump Coal Rate in Haizhou Coal Mine" was completed, and the number of blast holes was reduced by using low-power explosives with detonation velocity of 2700~3200m/s, air column filling, optimizing hole layout parameters and millisecond delay blasting technology. The lump coal rate increased by 2.83%. Study on optimization of blasting technology in large open-pit coal mines 1992. Through the test in Antaibao open-pit coal mine, the explosive quota of this mine was reduced from 0.45kg/m3 to 0.3 19 kg/m3, the comprehensive cost was about 10536 million yuan, and the stripping amount was increased by 200.536 million yuan.

In addition, we have successfully developed B2 and B3 liquid explosives, liquid explosives mixed trucks and four-way initiators in cooperation with Shenyang Military Industry Corps, and completed the blasting vibration test and shock absorption technology research in Antaibao, Zhungeer, Huolinhe and Fushun West Open-pit Mine.

2 Research on Slope Stability and Monitoring Technology

2. 1 Study on slope stability

The research on slope stability technology began in the mid-1950s. Haizhou open-pit coal mine was put into operation in 1953. Shortly after the reconstruction of Fushun West Open-pit Coal Mine, many landslides occurred on the non-working face, which seriously affected the normal production and equipment safety. Aiming at the landslides in the above two mines, the slope stability research work was started. The main research contents are engineering geological conditions of non-working slopes, physical and mechanical properties of rocks, conditions for landslide formation and stability analysis methods, determination of slope instability range and prevention measures.

196 1 year, four large landslides of one million cubic meters occurred in Fushun West Open-pit Mine, among which the No.3 landslide endangered the safety of the coal extraction roadway in Xida Lane. The scientific researchers of our institute participated in the governance working group composed of many departments, and completed the design and construction of measures such as slope cutting, weight reduction, dewatering and reinforcement, which ensured the normal production of the hoisting system.

After this stage of research work, a set of theories and working methods of slope stability research in open pit mines have been established, a scientific research team has been trained, and a rock mechanics laboratory has been established. Slope engineering research has become the leading specialty of the Institute of Open-pit Mining Safety, and it is also one of the earliest professional units to carry out slope engineering research in China. He also participated in the demonstration of non-coal open-pit mines and the landslide of the Three Gorges of the Yangtze River for many times. With the development of open-pit coal mines in China, it has successively undertaken major scientific research projects of the State and the Ministry of Coal, and completed the slope stability research and landslide prevention work of Fushun, Fuxin, Pingzhuang, Antaibao, Zhungeer, Xiaolongtan and Yima open-pit coal mines. Up to now, * * * has completed more than 60 scientific research projects, of which 12 has won the first, second and third prizes at the provincial, ministerial and national levels respectively.

2. 1. 1 basic research

(1) engineering geological survey technology. The geological structure and occurrence conditions of rock strata, especially the conditions of weak rock strata, are the internal factors of landslide formation. Finding out geological structure is the basis of determining landslide scale, sliding mode, stability analysis and prevention measures. Conventional methods are surface geological structure investigation, drilling and tunnel exploration.

With the development of radar detection technology and seismic wave detection technology, boreless exploration of strata and geological structures has been realized. In the 1993 research project on the stability of the southwest slope of Fushun West Open-pit Mine, the occurrence and distribution law of soft tuff affecting the slope stability in this area were successfully determined by using shallow geological radar instruments.

In the aspect of rock mass structure analysis, according to the characteristics of rock mass cracks, random simulation, computer digital simulation and QD classification are used to determine the integrity of rock mass, so as to calculate the influence of rock mass structure on slope stability.

(2) Hydrogeology and groundwater monitoring. The existence of groundwater in the slope rock mass not only weakens the rock strength, especially reduces the shear strength of the weak layer, which makes the slope slide along the weak layer. In addition, with the increase of groundwater level, the uplift force reduces the anti-sliding ability of slope. Therefore, groundwater exploration mostly adopts surface investigation and drilling hydrological holes. Take rock samples to measure the water content of rocks, conduct stratified water injection test, determine the water-bearing law and hydraulic connection of rock strata, and establish hydraulic model.

Piezoresistive groundwater monitoring system was developed in the seventh five-year national key scientific and technological project "Development of slope safety monitoring system", which can measure groundwater pressure at any time, and has the characteristics of high precision, high resolution, large output signal, centralized control and automatic recording, which improves the monitoring level of groundwater.

(3) Mechanical properties of rocks. The study of physical and mechanical properties of slope rock mass and index test provide scientific basis for slope design, stability evaluation and treatment. Since 1960s, the in-situ testing method of roadway and slab has been adopted. In order to cooperate with the field test design, a special pressure box and jack are developed. The mechanical indexes of various soft rocks in Fushun and Fuxin open-pit mines are measured by this method, which provides a reliable basis for slope stability evaluation and treatment.

Since 1970s, the construction of rock mechanics laboratory has been strengthened, and Djy-4 quadruple isostrain direct shear instrument, GJY-2 high-pressure isostrain direct shear instrument, SJ-IA triaxial shear instrument, XD- 1 point load instrument, JQ-200 rock shear rheometer, soil rheometer and other test equipment have been purchased successively, as well as physical property index measuring instruments. In order to simulate the rheological strength of rocks in natural state, a constant temperature and humidity rheological laboratory was established.

It is very important to determine the mechanical index of bulk materials in dump for slope design and stability evaluation of dump. 1988, SZ-30-2A triaxial shear apparatus was purchased, and the laboratory of granular materials mechanics was established. The sample is made of bulk materials in a certain proportion of particles. The device has successively completed the determination of material mechanical indexes of Antaibao, Zhungeer, Wu Baoshan, Fushun, Yimin River and other open-pit mines, providing parameters for slope stability evaluation of dump. It is in the triaxial test that the relationship between the dissipation speed of pore water pressure and gravity and loading speed in the loess basement aquifer is found, and the cause of landslide in the dump under the condition of high-speed dumping is revealed.

(4) Landslide model and simulation technology. The landslide model of open-pit coal mine has the characteristics of sedimentary strata, which is mainly controlled by weak strata. Bedding, joints and faults are the main factors controlling the landslide mode.

1984 a domestic bottom friction simulation test device has been built in our hospital, which can automatically adjust the speed stepless. The bottom friction method is a two-dimensional physical model, which is suitable for the combination of similar materials in jointed rock mass. It can replace mining engineering activities to change the shape of the model and predict the deformation law and landslide mode of the future slope.

In the seventh five-year plan national key project "Study on the stability of the north slope of Fushun West Open-pit Mine", the formation conditions, deformation process and law, stress distribution and deformation range of the toppling slide are successfully simulated by discrete element method. It can be clearly seen from the computer mathematical model that the rock mass to the north of the F 1 fault in the upper part of the slope is the main thrust section, which pushes the northern wing of the syncline structure to the south of F 1 to topple (the northern wing of the syncline structure has a large dip angle and the southern wing is gentle), thus pushing the southern wing to slide, forming a toppling sliding landslide mode.

(5) Slope stability analysis method. In the stability analysis of the north slope of Fushun West Open-pit Mine, the stability analysis theory and calculation method of curved wedge and dumping slip are put forward in view of the landslide and dumping slip deformation of curved wedge. Reach the world advanced level.

Sarma slope stability evaluation method is a new development of limit equilibrium analysis method. Its characteristics are: it can be used to determine the stability of various sliding surface slopes such as plane landslide, wedge landslide, arc landslide and non-arc landslide, and can be used to analyze geotechnical slopes with various complex sliding surfaces. Allowing different sides and bottom surfaces of the strip to be endowed with different strength parameters; It considers the influence of groundwater pressure and earthquake factors on slope stability. The Institute of Open-pit Mining Safety took the lead in introducing this method into China. The slope analysis of Fushun west open pit mine is described in detail, and the assembly language program suitable for HP4 1CV programmable calculator is compiled. And this analysis method is extended to other industries in China, so that this method is widely used.

(6) Landslide prevention technology. (1) Cut the slope to reduce weight, and adopt top-down measures to clean the gentle slope. The gentle slope plays a role in stabilizing the slope. (2) Anti-slide pile reinforcement: reinforced concrete piles are used to reinforce the slope. ③ Controlling the change of groundwater pressure, groundwater is an important factor affecting slope stability, and most slope instability and failure are caused by groundwater out of control. Therefore, horizontal drainage holes and roadway drainage are widely used to reduce groundwater level and prevent slope sliding. Therefore, a set of horizontal drainage hole design method, computer groundwater network model and groundwater pressure monitoring system are established.

2. 1.2 Study on Slope Stability of Loess Basement Dump

199 1 year/kloc-0 10 at 0: 00 on October 2910, a large-scale high-speed landslide occurred in the south dump of Antaibao open pit mine, and the sliding body slipped out nearly 300m meters instantly. The landslide volume is about1000 ~130,000 m3, which is an open-pit coal mine landslide in China. Landslide destroyed Pingshuo highway, mining area highway, ore washing workshop, drainage ditch and other facilities, causing huge losses. I undertook landslide research and treatment engineering design. The mechanism of sitting high-speed landslide on loess foundation is found out, and comprehensive control measures such as cleaning, slope cutting and weight reduction, water control and local support are put forward. After treatment, the slope has reached stability, and Pingshuo highway and mining area highway have been restored. Only restoring Pingshuo highway without winding can save more than 654.38 billion yuan.

In the study of landslide in the dump with loess as the basement, the concept of soft layer of basement soil evolution under high load is put forward, and its formation mechanism is studied, and the corresponding microstructure model is established. The corresponding stability evaluation method and engineering governance method are established. In the study of slope stability of Antaibao mine west dump and Zhungeer Heidaigou open-pit mine north dump, the above theory is applied to evaluate and control, so that the height and capacity of dump are improved. Among them, the west dump is increased by 30m, and the capacity is increased by 17%.

2. 1.3 Study on Slope Stability

In 1980s, Fushun, Fuxin, Pingzhuang and other open-pit coal mines successively entered deep mining, with slopes as high as about 300m, and the complicated geological conditions and mining activities caused the slopes to slide many times.

In order to solve this problem, since 1982, the research on the slope stability of the northwest slope of Fushun West Open-pit Mine and the national "Seventh Five-Year Plan" key project have been carried out successively, and the calculation methods such as slip, toppling slip deformation and three-dimensional analysis of the wedge of the bending machine have been summarized. It is proposed that the appropriate coal pressure in some sections should be slowed down to the boundary of the boundary slope; The combination of horizontal drainage hole and drainage roadway reduces the water pressure inside the slope; Grouting reinforcement, long bolt reinforcement and anti-slide pile reinforcement are adopted locally; Strengthen the mining in the west area, realize the slope treatment measures such as internal dumping, and ensure the slope stability.

1995 completed the "study on computer system of slope engineering evaluation in deep open pit mine", and compiled CAD software including engineering geology, hydrogeology, rock mechanics, slope deformation dynamics, stability analysis and engineering design. It provides scientific basis and means for real-time evaluation of slope stability in open pit mine and realizes the modernization of slope management.

2.2 Slope deformation monitoring technology and instruments

The conventional monitoring method is surface rock movement observation. This method can only understand the change of slope rock mass deformation after surface displacement, but can't understand the early deformation law of deep rock mass, as well as the location, deformation mode and scope, deformation development trend and so on. Especially, understanding the early deformation law of slope will win valuable time for landslide control. Starting from 1978, our institute began to study the internal deformation observation methods and instruments. After repeated tests in Haizhou Mine, Jiaoping Open-pit Mine and Fuxin-Mabei Open-pit Mine, a strain-type landslide displacement sensor was developed at 1982.

1983, KS- 1 high-precision strain inclinometer was developed on the basis of strain-type landslide displacement sensor, which can not only observe the internal deformation of rock mass, but also realize portability, maneuverability and multi-purpose of one machine.

In the "Seventh Five-Year Plan" national key project "Development of slope safety monitoring system", our institute developed the PSH type two-way servo accelerometer inclinometer monitoring system on 1989. Among them, the inclinometer adopts servo accelerometer (originally used for aviation equipment monitoring) as the inclinometer element, and two inclinometers with a difference of 90 degrees are placed in the inclinometer. The angular accelerometer enables the same inclinometer to measure the inclination of two vertical planes at the same time, thus completing the bidirectional inclinometer. The inclinometer is equipped with a ground intelligent recorder to record the data measured by the inclinometer.

After the successful development of PSH inclinometer, the working slope of Fushun West Open-pit Mine, the non-working slope of Fuxin Haizhou Mine, the slope of Antaibao South Dump, the slope of Anjialing Dump and the slope of Xiaolongtan Bubog Mine have been monitored successively, providing reliable data for slope stability analysis and landslide control. In recent years, the cable-free test system and azimuth instrument of inclinometer have been developed, and the inclinometer system of PSH bidirectional servo accelerometer has been further improved, making the measurement more accurate.

1992 completed the research on the monitoring device of slope rock mass settlement, and realized the monitoring of vertical deformation inside rock mass. Through inclinometer and settlement instrument, the slope monitoring of open pit mine has realized three-dimensional dynamic observation. 1995 developed a fixed displacement sensor for large displacement in the middle and late stage of landslide, which realized the monitoring of large displacement in the middle and late stage of slope deformation and made the monitoring system of underground displacement of slope more perfect.

3 Research on the Application of Intelligent Technology

3. 1 application of computer technology in open pit mine

Our institute set up a computer center in the early 1980s, and started the application research of computer technology in open-pit coal mines. We have undertaken and completed such projects as "Computer Management System of 75B Auto Parts in Huolinhe Mining Area", "Overall Planning and System Analysis of Feasibility Study Management System of Zhungeer Coal Company's Phase I Project (including coal, electricity and transportation)," Establishment Method of Stratified Deposit Geological Model and Heidaigou Open-pit Mine Geological Model "and" Open-pit Mine CAD Survey Acceptance System ". The application of this achievement in mines has greatly improved the management level. Especially after the application of "CAD measurement and acceptance system", it saves a lot of field measurement and calculation work, improves the calculation accuracy and reduces the labor intensity.

Since 1993, the optimal dispatching system of electric forklift in open pit mine has been studied, and the optimal dispatching system of electric forklift in COTOD (Ketongda) open pit mine has been jointly developed with Beijing Changzheng Hangxin Satellite Navigation Technology Co., Ltd. of China Academy of Launch Vehicles. The system was put into operation in an open pit mine of Yimin Huaneng East Coal and Electricity Co., Ltd. from 65438 to 0997 and passed the national appraisal from 65438 to 0998.

The system can track and display the working position and state of the scraper in real time by collecting information such as the position, state, speed, running direction and time of the scraper, and optimize the operation of the dispatching fleet. Timely and accurate query and statistics of the current production situation; It plays a role in optimizing scheduling, accurately implementing production plan, improving equipment efficiency and economic benefits.

After adopting COTOD system in Yimin open-pit coal mine, the production efficiency increased by 8%. The performance-price ratio of the system is obviously better than that of similar foreign products, which fills the gap in the domestic independent development of open-pit mine optimal dispatching system.

3.2 Equipment performance testing and production monitoring technology

Mine measurement and control technology includes the testing of mining equipment and the monitoring of production process.

In the 1980s, large-scale open-pit coal mines introduced a large number of large trucks and domestic cars. In order to test the performance of large trucks and their adaptability to mine conditions, our institute purchased advanced testing instruments from Japan, Switzerland and Germany, and established a performance testing laboratory for mining trucks. Undertake state affairs

The performance comparison test of large dump trucks, the performance test of 108T mining dump truck and SF-3 103t cold-resistant 108t electric wheel dump truck were issued by the Major Equipment Department of our institute. There are nearly 100 tests on basic performance, fuel consumption, vibration ride comfort, and applicability of mine operation.

In recent years, the monitoring of production process has become a research hotspot. The optimized dispatching system of truck electric shovel in He Yimin Open-pit Mine has been successfully developed, and the real-time monitoring and dispatching of truck running state in open-pit mine has been realized. The newly developed GL-6kV high-voltage power supply protection cabinet is mainly used for power supply and leakage, overcurrent and short-circuit protection of 6kV neutral ungrounded power supply system of high-voltage electrical equipment in coal mines. Telemetry and remote control system monitors the current and voltage values of high-voltage electrical equipment in real time. In Yimin open-pit mine, the centralized control of power supply status of multiple electric shovels was realized by using this protective cabinet.

Looking forward to 46 years of fruitful results, it is gratifying and inspiring. Looking ahead, the task we face is still very arduous. With the preparation of Anjialing Open-pit Coal Mine Phase II, Pingshuo No.3 Mine and Yimin Open-pit Coal Mine, the development of Shengli Coalfield and the expansion of Zhungeer Heidaigou Open-pit Coal Mine, China's open-pit coal mining industry will take a new step. To this end, we will continue to reform the scientific research system, overcome technical difficulties, and develop advanced technologies suitable for the production development and management level of large open-pit coal mines in China. It is necessary to study the mining technology suitable for various geological conditions, especially the mining technology without transportation; It is necessary to further study the application of computers in open-pit mines, realize the computer design of large-scale open-pit coal mine production plans, monitor and optimize the scheduling of production processes, and improve the management level of modern open-pit mines; Further improve the optimal dispatching system of electric forklift and do a good job in popularization; Study the blasting technology under the condition of high section of hard rock to improve the blasting effect and give full play to the efficiency of mining equipment; Strengthen the study of slope stability and the development of new slope deformation monitoring instruments; Carry out in-depth evaluation of mine geological disasters and environment, and study the comprehensive utilization of abandoned mines; Strengthen the research on detection and monitoring means and technology; Pay attention to the construction and renewal of experimental means; On the basis of actively developing technology development services, we will increase investment in basic research and attach importance to personnel training.