Mining machine collapse

1. Hello, it's very difficult to dig now. I can't dig one for several months. I can do stocks. Now the stocks are in the low position, so the chances are very big

2.

Some time ago, we also said that SSD and memory price increases are too exaggerated. Unexpectedly, only a few months later, a more crazy wave of price increases will come, but the object of this price increase is graphics card! Over the years, the price of graphics card has increased, but almost for the same reason: mining! I still remember a few years ago, when mining was popular, many a cards were hard to get. As a miner of that year, aka also had a deep understanding

Second, second-hand, try not to choose a card. At present, the a card of LEIYU is not only expensive, but also a lot of a cards are the remains of long-term mining. It's hard to say whether they can work normally. If you want to buy second-hand cards, you'd better consider the previous generation of flagship cards, and still recommend N cards, gtx980 or gtx970. You can still buy them at about 1500 yuan! Game performance will not be much different than rx580

Of course, the better way is to pray for a huge mine disaster every day! Then all the problems will be solved

3.

Li Yue, Zhou Yaoqi

(Dongying 257061, Shandong Province, open laboratory of Geochemistry and lithospheric dynamics, China University of Petroleum (East China))

Introction to the author: Li Yue, female, born in Cangzhou, Hebei Province in December 1979, graated from petroleum geology, China University of petroleum in 2002, with a bachelor's degree and a doctoral degree. Research direction: geological resources and geological engineering, Email: lyysy_ [email protected]

On the basis of using MEMS technology to monitor the fracturing process of granite samples, the application of MEMS technology in predicting gas explosion is discussed by applying the principle of fracture monitoring. In the experiment, four batches of microcracks were observed when the rock samples were pressed continuously by a press. The three groups of micro fractures before the main fracture are the result of the internal fracture concentration and mutual connection, which can be regarded as the precursor before the earthquake. The main fracture occurs in macroscopic view. Based on the above principle, the technology can be used to predict the mine earthquake caused by mining and the mine explosion caused by natural earthquake

key words: MEMS technology fracturing micro fracture coal mine disaster

Application of MEMS in forecast of gas disaster of coalmine

Li Yue, Zhou Yaoqi

(geochemistry & Lithosphere dynamic open laboratory, China University of petroleum, Dongying 257061

Abstract：Based on the monitoring to the fracturing process of the granitic sample by MEMS，applying the monitoring principle，we discussed the application of MEMS in forecasting the gas blowing up.In this experiment，continually forcing to the sample， we observed four series of micro-fracture.The anterior three series of microfracture before the main fracture were because of the crack in the sample centralizing and connecting，which was regarded as the portent of the earthquake.The main-fracture proced the crack in macro.Based on the beforementioned principle， it was concluded that the forecast of mine blast resulted from the mining and crude earthquake had the good effect by this technology.

Keywords：MEMS fracturing micro-fracture MEMS (micro electro mechanical systems) is usually called micro electro mechanical system technology, which means that it can be mass proced, including micro mechanism, micro sensor, micro actuator, signal processing and control circuit, including interface, communication and power supply< Sup > [1] < / sup >

mine accidents account for a considerable proportion of major casualties in recent years, and gas explosion and earthquake inced by construction bring great threat to the workers. This paper mainly discusses the application of MEMS technology in the prediction of coal mine disasters on the basis of experiments

1 experiment

the experiment mainly uses the sensitive characteristics of MEMS technology to observe the instantaneous response of the sensor when micro fracture occurs by monitoring the fracture process of granite

1.1 brief introction of samples and observation system. Processed into 50 × fifteen × 5 cm < sup > 3 < / sup >. Granite has uniform grain structure, mainly composed of quartz, feldspar, biotite and a small amount of heavy minerals. The maximum phenocryst size of feldspar is about 5mm, and the average grain size is 0.5-3mm. Biotite is usually linear along the edge of quartz feldspar grains (see Figure 1)

Fig. 1 microstructure of granite (orthogonal polarization) × The sensor adopts four single component acceleration sensors of me ms-1221 l proced by Dongying micro technology development company. The sensitivity is 2 V / g, the resolution is 10 < sup > - 4 < / sup > G, and the frequency range is 0 ~ 1000Hz. The data acquisition and analysis system is a general data monitoring and analysis software RBH general developed by dongyinggan micro technology development company

WE-300 press was used in the fracturing experiment (Fig. 2). The observation system is shown in Figure 2 (b) and figure 3

Fig. 2 experimental press and observation system

A is WE-300 experimental press, B is the sensor placement and compression support position of rock sample observation system

Fig. 3 head up view of observation system

in which No. 1, 2, 3 and 4 are four sensors, and sensors 1 and 4 are close to the edge of rock block. Four sensors are on a horizontal line. The distance between the center of sensor 1 and sensor 2 is 10 cm, and that between sensor 3 and sensor 4 is the same. The radius of the sensor is 2.5cm

1.2 discussion on the experimental process and data; Then, the four sensors are placed on the rock sample in turn (Fig. 3), and their respective positions are recorded. At the same time, the sensors are connected with the data acquisition and analysis system, so as to record the signals from different parts of the micro fracture

time recording starts from 0 seconds, and the sampling frequency is 4000Hz. The application process of pressure is graal. The pressure increases graally from 0 kn. The spectrum of noise is recorded when the data changes. When the pressure increases to such an extent that the internal structure of rock sample changes, the spectrum changes immediately. The change process of spectrum will be discussed in the following section. Red represents the spectrum of sensor 1, black represents the spectrum of sensor 2, Blue represents the spectrum of sensor 3 and yellow represents the spectrum of sensor 4. In the nearly 360 second fracturing process, the real sample fracture is completed in the last minute, that is, 302.290 ~ 303.826 s, respectively; 305.599～307.135 s Four batches of microfractures occurred in 316.793-318.329 s and 357.923-360.258 s. Except for the last batch of microcracks lasting more than 2S, the previous three batches of microcracks lasted less than 1.5 s. Each batch of microcracks is composed of a group of dense microcracks, and the ration of a single microcrack is generally less than 50 ms

1.2.2 data recording and analysis of fracturing process

next, the spectrum characteristics recorded in 10 representative time periods are selected for discussion in chronological order. Due to technical reasons, the accuracy of the sensors currently used is not enough to distinguish the accurate time of the received signal when the fracture occurs. We will graally solve this problem in the future work

(1) noise spectrum after 0.291-31.826s compression (Fig. 4): shortly after the beginning of compression, although the noise received by each sensor is different, generally speaking, the main frequency of noise is concentrated in the low frequency region of 50-300hz and the high frequency region of 400-750hz. The amplitude of sensor 4 is slightly lower than the other three because it is far away from the oil pump, The frequency difference is distributed in two lower and higher regions between 20 and 200Hz and 600 to 750Hz. The difference of noise recorded by different sensors is mainly related to their simultaneous interpreting. p>

(2) 31.990-33.526s noise spectrum (Fig. 5): compared with the noise spectrum after 0.291-31.826s compression, the amplitude of the noise is nearly doubled, but the frequency is still concentrated in the low frequency region, and the high frequency amplitude is suppressed compared with the low frequency region, which indicates that the internal structure of the rock sample is affected by the pressure, The sudden increase of noise amplitude may be the result of uneven pressure exerted by oil pump

Fig. 4 0.291-31.826s noise spectrum after compression start

Fig. 5 31.990-33.526s noise spectrum

(3) 300.665-302.201 s noise spectrum (Fig. 6): near the occurrence of micro fracture, the noise level further decreased, especially the position of sensors 2, 1 and 4 decreased significantly. The noise level of position 3 is relatively high

Fig. 6 300.665-302.201s noise spectrum

(4) 302.290-303.826s frequency spectrum of microcracks (Fig. 7): This is the frequency spectrum characteristics of the first batch of microcracks. It is obvious that the amplitude is abnormal, and the data obtained by different sensors are different: the frequency range of sensors 1 and 2 is about 700-800hz, while sensors 3 and 4, especially sensor 3, are greatly affected by noise, and their response to micro fracture is not obvious. The frequency range of sensor 3 is about 500-600hz, and that of sensor 4 is about 650-750hz. The first batch of microcracks only changed the fine structure of the rock sample, but there was no change in the macro

Fig. 7 frequency spectrum of 302.290-303.826s microcrack occurrence

(5) frequency spectrum of 305.599-307.135s microcrack occurrence (Fig. 8): compared with the frequency spectrum of 302.290-303.826s microcrack occurrence, the frequency range is about 650-750hz

(6) 307.612-309.147s noise spectrum (Fig. 9): the rock sample will not rupture again after the micro fracture, which is basically the same as the noise spectrum at the beginning, but the high-frequency noise is relatively higher than the low-frequency noise, indicating that the internal structure of the rock sample has changed

Fig. 9 307.612 ~ 309.147s noise spectrum

(7) 316.793 ~ 318.329s frequency spectrum of microcracks (FIG. 10): the third batch of microcracks has higher strength and amplitude than the first two batches of microcracks. With the increase of pressure, on the basis of the previous fracture, when the internal fracture of rock sample develops and penetrates again, the rock sample will fracture. The frequency range of micro fracture recorded by sensor 1 is about 350-500hz, the frequency range recorded by sensor 2 is about 450-550hz, and the frequency range recorded by sensor 3 is about 400-500hz, The frequency range recorded by sensor 4 is about 650-750hz

Fig.10 frequency spectrum of 316.793 ~ 318.329s micro fracture occurrence

(8) 326.534 ~ 328.070s noise spectrum (Fig.11): after the occurrence of the third batch of micro fracture, because the rock sample has proced cracks, the continuous pressure will not have a great impact on the rock sample in a very short time, so it still shows the frequency spectrum characteristics of press noise

Fig. 11 326.534 ~ 328.070s noise spectrum

(9) 358.723 ~ 360.258s frequency spectrum of main fracture (Fig. 12): after continuous pressurization, the rock sample has stronger fracture on the basis of previous micro fracture, namely main fracture. From the data we collected, we can see that the rupture amplitude is much larger than the previous rupture, and the peak value has an obvious trend of moving to the low frequency region. The frequency range of each sensor also has obvious differences: the frequency range of sensor 1 is 300-500hz, the frequency range of sensor 2 is 200-300hz, the frequency range of sensor 3 is 350-550hz, and the frequency range of sensor 4 is 500-700hz. Because the final fracture surface is located between sensors 2 and 3, and the final fracture extends to sensor 2, the amplitude and frequency of micro fracture recorded by sensors 2 and 3 are relatively low, especially sensor 2. However, the microseismic amplitude and frequency recorded by sensors 1 and 4 far away from the fracture surface are much higher. This may be related to the smaller rock sample, the farther away from the fracture surface, the greater the displacement of the sensor<

4. Mining enterprises are generally recognized as high-risk instries. The working environment is hard, and the probability of casualty accidents is much higher than other jobs. Although the state has adopted very strict regulatory measures, mining enterprises have also made great efforts to constantly improve and optimize the working environment, improve the level of mechanization and automation, and implement standardized and standardized operations, However, in recent years, mine casualties are still high, and serious accidents occur one after another. The reasons are driven by economic interests, and more of them are insufficient investment, incomplete facilities, low quality of personnel and poor quality; Three violations & quot; It's caused by
I. characteristics of casualty accidents in mining enterprises
harmfulness. The occurrence of accidents will cause varying degrees of harm and loss in terms of people, money and materials. At the same time, it will also have a certain impact on social stability, economic development and family happiness. Understanding this feature will improve people's sense of social responsibility and economic responsibility for safety
risk (precursor). Before the accident, the state of the system (human, machine, environment) is unstable, that is, there is an unsafe state, that is, the potential accident. Understanding this, we can prevent the paralysis of lax thinking and complacency, and take corresponding corrective measures as soon as possible to prevent the occurrence of accidents
repeatability. That is to say, the occurrence of accidents has the characteristics of repetition. Mastering this feature will play a positive role in formulating the corresponding preventive measures and preventing the recurrence of similar accidents. At the same time, it also requires people to adhere to & quot; Three not let go & quot; Principle
regularity. The time and place of the accident and the severity of the accident consequence are accidental, but we can find out the regularity of the accident through the analysis of the accident statistical data, so as to provide a strong basis for formulating the correct preventive measures
preventability. Any accident can be prevented as long as we take positive preventive measures correctly and timely and strive to create a good safe proction environment. To realize this, it is helpful for us to strengthen our faith and prevent casualty accidents< 2. Types of mine casualty accidents
mine casualty accidents are mainly concentrated in object strike, roof fall and rib spalling, falling from height, collapse, mechanical injury, vehicle injury, etc. the cause analysis of national non coal mine casualty accidents in 2007 is shown in the figure< According to the scope of roof fall and the number of casualties, it can be generally divided into three types: large roof fall, local roof fall and loose rock fall. Large roof fall usually occurs in the mining of sedimentary minerals, but rarely in metallurgical mines. Local roof fall and loose rock fall are collectively referred to as roof fall accidents
this kind of roof fall accidents often occur in the following situations: in the working face with broken roof; In the working face where the bedding, joints and faults are relatively developed and easy to be separated; In the mine, ultra deep mine, blasting ventilation to eliminate improper working face
the occurrence of roof fall accidents is generally related to many factors such as mine geological conditions, proction technology, organization and management. According to the accident classification statistics, 45.6% of the accidents were caused by proction organization and management, 44.2% by material and technology, and only 10.2% by risk-taking operation< (1) proction organization and management
1. Unreasonable selection of mining methods
unreasonable selection of mining methods is a major cause of roof fall accidents
2. Unreasonable roof support method
another major cause of roof fall accident is unreasonable support method or untimely support in working face or large section driving. When the roof rock near the working face is relatively broken and the structure is relatively developed, the support method is unreasonable or the support is not timely, which is extremely flammable and explosive, resulting in roof falling or spalling, causing accidents
3. Improper pumice treatment
most of the loose stone caving in the roadway occurs within 10 meters from the working face, and most of the loose stone caving in the stope occurs when the roof of the stope is not too high
improper handling of pumice, unskilled removal technology, poor inspection, carelessness or even no inspection are one of the causes of roof fall accidents. Most of the casualties caused by improper handling of pumice are caused by the lack of comprehensive and detailed inspection of the working face top before pumice handling, improper standing position and unskilled technology of the removal workers
4. Improper use of protective equipment
when working in the mine, roof fall accidents are often enlarged e to incorrect use of protective equipment< Personnel management can't keep up with
first, there are many new workers in the mine, they don't understand the underground working environment, and they lack the training of safety knowledge and skills, so they can't connect the old with the new, and they can't timely and effectively & quot; Knock on the gang and ask the top & quot; And cause an accident
Second, the underground management personnel do not pay attention to the roof management, and there is no effective roof management method and supervision and restraint mechanism, so that the roof management is lax, and the small roof fall accidents without casualties are continuous, and the roof fall accidents with casualties are inevitable< (2) preventive measures for roof fall accident
1. Timely adjust mining technology, ensure reasonable exposure space and mining sequence, and effectively control ground pressure
it is necessary to strengthen the experimental research of mine geological work and mining methods, continuously improve the original design of mining methods, find out the efficient and safe mining methods suitable for different geological conditions of the mine, increase the mining intensity and deal with the goaf in time. In order to control the stability of the stope roof, there must be a reasonable mining sequence, so the mining sequence of two adjacent groups of veins should be determined reasonably; According to different geological conditions and mining methods, the technical indexes such as the exposed area of stope and the height of goaf should be strictly controlled so that the stope can be completed ring the period of stable ground pressure
2. The inspection, observation and treatment of roof should be strengthened to improve the stability of roof. The inspection and treatment of roof loose stone is a regular and very important work. It is necessary to fix a special person to work according to the specified system, so as to ensure the safety of roof proction and prevent the occurrence of roof loose stone falling accidents. For some dangerous stopes, scientific methods should be used to observe the roof as far as possible under the conditions of technology and economy. At present, optical stress meter, geophone and rock movement observation are the most economical and convenient observation methods in China. It is necessary to observe and explore the law of rock movement of different rocks and grasp the roof condition scientifically. It is necessary to deal with the unstable working roof in time, and take scientific and effective measures (such as shotcrete and anchor support) to prevent roof fall
3. Scientifically and reasonably arrange the position, specification, shape and structure of the roadway and stope
it is necessary to avoid arranging the roadway engineering near the geological structure line, because the pressure perpendicular to the geological structure line is the biggest, which is the main factor of rock mass change and fracture
it is necessary to avoid the layout of roadway engineering near the weak surface of geological structure such as fault, joint, fracture zone in stratum, argillaceous interlayer, etc. Because the projects arranged in these places are more prone to roof fall. If the roadway engineering must pass through these zones, corresponding supporting measures or special construction schemes should also be adopted
the shape and structure of roadway and stope should meet the requirements of surrounding rock stress distribution as far as possible. Therefore, the roof of roadway and stope should be arched as far as possible. Because the secondary stress of surrounding rock is not only related to the original rock stress and lateral pressure coefficient, but also related to the shape of roadway. When the arch shape is adopted, the construction is not difficult, the roof pressure is not too concentrated, and the roof stability is good< Strengthen the roof management and improve the technical level of roof management
first, strengthen the safety ecation and the training of safety technology knowledge, improve the technical level of safety management personnel at all levels, and establish & quot; Safety first & quot; The roof management system of group inspection, group prevention and group governance should be established. Special crowbar shall be provided at each working face, special person or part-time manager shall be set up to be specifically responsible for the risk elimination work of each working face, warning signs shall be set up, shift handover system shall be well done, and management of key hazard source points shall be carried out
the second is to summarize the experience and lessons of roof management in combination with the actual situation of the mine, and formulate a complete set of roof management standards for roadway construction from the provision of geological data, roadway design, roadway maintenance technology and construction management, so as to provide technical support for scientific and effective roof management< (3) self rescue and mutual rescue in case of roof fall
1. Self rescue measures in case of roof fall
(1) quickly retreat to a safe place. When it is found that there is a sign of roof falling in the working place, and it is difficult to take measures to prevent the roof falling, the best disaster avoidance measure is to leave the dangerous area quickly and retreat to a safe place
(2) when in danger, you should stand close to your body or go to the wooden crib to avoid the disaster. From the actual situation of roof fall in mining face, it is very rare that the roof fall along the rock wall. Therefore, when there is no time to retreat to a safe place in case of roof fall, the person in danger should stand close to the rock to avoid the disaster, but pay attention to the wall to help hurt people. In addition, the pillars may be broken or knocked down when the roof falls, but it is impossible to crush or push down the qualified wooden stacks under normal circumstances. Therefore, if the person in distress is close to the wooden crib, he can withdraw to the wooden crib to avoid the disaster
(3) send out a call for help signal immediately after distress. The main injuries of roof fall are smashing, burying or blocking. After the fall is basically stable, the person in danger should immediately use the methods of calling and knocking (if the material or rock block may cause a new fall, it can not be knocked but can only be called) to send out regular and uninterrupted call for help, so that the rescue personnel and evacuation personnel can understand the situation of the disaster and organize forces for rescue
(4) people in distress should actively cooperate with external rescue work. People who are buried and pressed by rocks and materials after roof fall should not panic. When conditions do not permit, they should not resort to violent struggle to get out of danger, resulting in the expansion of the accident. People blocked by roof fall should maintain their own safety in an organized way at the place of distress, build escape channels, cooperate with external rescue work, and create good conditions for early escape
2. Measures for rescuing people in danger of roof fall
(1) to ensure the safety of rescue personnel. The rescue work should be carried out under the command of the leaders and experienced workers in the disaster area. The rescuers should check the supports near the roof fall site, and deal with the damaged, twisted and deformed columns immediately to ensure the safety of the rescuers, and set up a smooth and safe exit
(2) support the roof fall according to local conditions. According to the situation of roof collapse, on the premise of ensuring the safety and convenience of rescue personnel, the roof fall should be supported according to local conditions. In case of partial roof fall in mining face, the method of digging out beam socket, hanging metal roof beam, or digging out beam socket, erecting monocular shed can be used. The gap on the shed beam should be set up with wood, and the small wooden stack should be connected to the top, and the back should be inserted tightly to prevent the roof fall from further expanding
(3) rescue the buried personnel. After checking that the erected support is firm and reliable, a special person should be assigned to observe the roof, so as to clean up the falling rocks near the buried personnel, until the personnel in danger are rescued from the buried area. In the rescue

5. All members of the Liu Hulan group participate in the "democratic management network" of the group“ We have set up six members, namely, political workers, proction planners, quality inspectors and economic accountants, who perform their respective ties and feed back each worker's labor performance to the indicator system month by month. " According to Zhang Qingping, under the scientific assessment of a set of index system created by them, the group has achieved amazing results in 42 years of "three no" (no waste procts, no personal accidents, no equipment accidents) and "two super" (overfulfilling proction tasks and saving targets year by year). In the past year, the group completed 72% of the work hours beyond the annual plan, 26 small-scale reforms, an annual increase of 200000 yuan, and completed the annual assessment index five months ahead of schele. In the eyes of the children of the second mining machinery school, all of these aunts have countless stories about dedication. However, this kind of dedication is not limited to the group. They donated money for the hope project and paired with poor primary schools...
over the years, 27 auditors in Hai'an County, Jiangsu Province have devoted their love to the vulnerable groups and paid back to the society. They firmly believe that as long as everyone gives a little love, the world will become a beautiful world. Last year alone, they donated 16000 yuan and more than 30 pieces of clothing. They visited the laid-off workers, veteran party members and veterans in poverty eight times. As they have helped and are still helping to change their destiny, may all the unfortunate people in the world be as lucky as those people. Always planted love seedlings, everywhere happy flowers. What Haian auditors have done and paid may be just a drop in the ocean, but happiness blooms when love comes. Their love is still continuing to contribute, they all hold such a belief: as long as the whole society perseveres in joint efforts, "vulnerable groups" will eventually "strong".

6. If you don't work hard, you will be sad.

if you don't cherish time, lazy people will get nothing.