The hottest research and development of coal mine

Research and development of coal mine safety technology in China Abstract This paper summarizes the new achievements made in the scientific research of coal mine safety technology in China during the "Eighth Five Year Plan" and "Ninth Five Year Plan", including the prevention and control technology of gas, coal and gas outburst, dust, fire and explosion, and puts forward suggestions for the recent scientific research work of coal mine safety technology

keywords new achievements in coal mine safety technology scientific research

1 preface

after half a century of development, China's coal industry has become the world's largest coal producer. In the past decade, due to the excessive total coal production, the diversification of energy structure and the development of high-efficiency energy-saving technology, the situation of coal supply exceeding demand has been caused. Experts predict that after 2025, due to the reduction of oil and natural gas resources, the status of coal in the world energy will rise. Generally speaking, China is a country rich in oil and coal, and coal shows a rigid change in the country's energy structure. It is estimated that coal will still account for 45% - 50% of primary energy in the middle of the 21st century. Therefore, coal is still the basic industry related to the sustainable development of the national economy

China is rich in coal resources, and the occurrence conditions and geological structure of coal seams are complex. There are many coal seams with spontaneous combustion, high gas, coal and gas outburst, which complicate the safety problems in coal mine production. Moreover, with the increase of mining depth and the development of high-yield and efficient mines, coal mines are facing many new safety technical problems

coal mine safety production is a major event related to national property and miners' lives, which has always been highly valued by the party and the government. The coal industry adheres to the policy of "safety first, prevention first", and under the guidance of the correct idea of "comprehensive management, overall promotion", vigorously carries out scientific research on coal production safety technology, especially during the "Eighth Five Year Plan" and "Ninth Five Year Plan", and has achieved new research results, which have been popularized and applied in coal mines

2 scientific research on coal mine safety technology

2.1 gas prevention and control technology

the harm of coal mine gas is mainly manifested in gas suffocation and minimum three explosion accidents; At the same time, a large amount of coal mine gas is discharged into the atmosphere, which increases the greenhouse effect of the atmosphere and worsens the meteorological conditions

prediction technology of coal seam gas content and mine gas emission: the gas desorption and influencing factors of geological exploration boreholes are studied, and a unified and relatively perfect prediction method of coal seam gas content and mine gas emission is established, which realizes the computerization, automation and standardization of coal seam gas content measurement and emission prediction, as well as the computerization, automation and standardization of mine gas geological mapping, with the prediction accuracy of 80 ~ 85%

Gas Drainage Technology: coal seam gas drainage is the fundamental measure of mine gas. During the "Eighth Five Year Plan" and "Ninth Five Year Plan", gas drainage in this layer, adjacent layers, through layers and goaf was implemented. The method and technological equipment of strengthening gas drainage in advance in fully mechanized mining face are studied. The test is successful. The gas drainage rate of the working face is increased by 20% through the Comprehensive Drainage Technology of 200-500m rock horizontal long drilling hole to drain the gas of the adjacent layer, the coal seam horizontal (250m) long drilling hole and presplitting controlled blasting to strengthen the gas drainage of this layer. Cement reaming technology is to use the drilling rig to spray high-pressure water jet along the borehole through the drill pipe and drill bit, and use rotary cutting to ream the borehole. Its effect is very obvious, and the gas drainage volume of a single hole is increased by 0.6 ~ 1.0 times

2.2 prevention and control technology of coal and gas outburst

China's outburst prevention technology has experienced the stages of safety protection, prevention and control technical measures and comprehensive prevention and control. The "detailed rules for the prevention and control of coal and gas outburst" formulated and promulgated in 1988 summarized China's national defense Outburst Technology after film forming as a four in one: prediction, outburst prevention measures, effect inspection and safety protection measures. Through the deepening during the "Eighth Five Year Plan" and "Ninth Five year plan", China's outburst prevention technology has been raised to the world's leading level

coal and gas outburst prediction technology: the outburst prediction index and critical value determination method of drilling method in mining face have been improved, and ATY and WTC predictors that comprehensively judge the risk of coal seam outburst based on the desorption characteristics of drilling cuttings and the amount of drilling cuttings have been successfully developed. After being popularized and applied in 50 bureaus and mines, the roadway of more than 150000 meters in the outburst coal seam has been safely excavated, the accuracy of non outburst prediction is 100%, the accuracy of outburst prediction is 60 ~ 70%, and the amount of disaster prevention works is reduced by 50%

a non-contact prediction method based on the measurement of AE acoustic emission events, gas emission status and coal wall temperature changes is studied, and a kj54 safety monitoring system is developed. The system has the functions of environmental monitoring and real-time monitoring of prominent hazards. In addition, the regional prediction of outburst coal seams was preliminarily tested by using geophysical exploration technologies such as radio wave perspective, natural electromagnetic radiation and geological radar

outburst prevention technology in addition to the technical measures of improving, perfecting and improving the mining protective layer, pre extracting coal seam gas, pre discharging drilling, deep hole loosening blasting and hydraulic punching, the outburst prevention technology of machine mining and machine excavation working face is mainly studied, and a set of outburst prevention technology of fully mechanized mining working face combining outburst area prediction, long hole control presplitting blasting and hydraulic loosening is established; In the machine driven working face, the full hydraulic outburst prevention drilling and cutting device and process technology that form a mechanical, hydraulic and operational integration with the roadheader are mainly studied; During the Ninth Five Year Plan period, qfz-22 portable disaster prevention drill was developed, which integrates the functions of strong drilling and anti sticking drilling. It is an efficient and portable drill for implementing advanced discharge drilling. For geological structure damage zone and serious outburst mine. The whole set of comprehensive treatment and prominent technology has been improved, and on the basis of the four in one outburst prevention measures, it has developed into a five step supporting comprehensive outburst prevention system of reasonable excavation deployment, prominent prediction and prediction, outburst prevention measures, effect inspection of measures, and safety protection measures

2.3 dust prevention and control technology

with the development of fully mechanized mining, fully mechanized excavation, high-yield and high-efficiency working faces, the problem of coal mine dust pollution is more prominent. Through the scientific and technological research during the Eighth Five Year Plan period, the dust prevention and reduction technology has made great progress

dust prevention technology in fully mechanized mining face: further improve and strengthen coal seam water injection, and implement long borehole deep sealing technology; The cement mortar hole sealing pump is developed, which solves the problem of difficult hole sealing, improves the effect of water injection and dust reduction in coal seams, and implements dust containing air flow control for the dust produced by coal mining machine. High pressure water spray dust reduction technology, the hydraulic support, the implementation of automatic control of the coal outlet water spray dust reduction technology, better reduce the dust concentration

dust removal technology of machine excavation face: the technical characteristics of the series of wet dust collectors have been improved and perfected, and the dust removal efficiency has been improved. In the past 10 years, in order to effectively control respirable dust, the bag type dust collector has been mainly developed. Its processing air volume reaches 230 ~ 250m3/min, the working resistance is 2083pa, and the dust removal efficiency of total dust and respirable dust reaches 99.5% and 95.5% respectively. The disadvantage is that it is large in volume and high in manufacturing cost. An air circulation dust removal device is developed for the transfer point The dust source at the transfer point is isolated from the external internal flow field with a closed cover, and the air flow is injected in the cover to remove dust circularly. In order to improve the dust reduction effect of water spray. The new dust reduction technologies of acoustic atomization, magnetized water and pre charged spray were studied

in order to strengthen and standardize the detection of respirable dust, AZF respirable dust sampler was developed during the Ninth Five Year Plan period, which can work continuously for 8h, and the separation efficiency conforms to the BMRC international curve, filling the gap of domestic long-term fixed-point respirable dust sampler. How to do the fatigue detection of bearings

2.4 mine fire prevention technology

Mining high-yield and high-efficiency working face of spontaneous combustion coal seam, the threat and harm of fire is greater. During the "Eighth Five Year Plan" and "Ninth Five Year Plan" period, fire prediction and real-time monitoring, efficient and clean fire prevention and extinguishing technology will be taken as key research contents

in terms of fire prediction: through the simulation test of spontaneous combustion of representative coal samples of anthracite, bituminous coal and lignite, the sensitive gas indicators that can be distinguished in the three stages of low-temperature oxidation, accelerated oxidation self heating period and intense oxidation of coal samples are obtained. At the same time, the fire beam tube detection system and its supporting mine fire multi parameter chromatograph, fire gas and temperature sensor are developed. In order to overcome the shortcomings of long-distance beam tube, such as lagging prediction, ponding in the tube and difficult maintenance, an economic fire prediction system combining beam tube and electrical measurement is developed, that is, the measured gas is sent to the underground substation by the beam tube, and the measured electrical signal parameters are directly transmitted to the ground monitoring room by each fire gas sensor, so as to conduct centralized real-time monitoring and prediction on the ground

in order to adapt to the conditions of fully mechanized mining with many and expensive equipment, Sui gas fire prevention and extinguishing technology based on nitrogen has developed rapidly. Hollow fiber membrane separation and carbon molecular sieve pressure swing adsorption separation technology are mainly used in China. Mining nitrogen generating units include KYZD-800 ground mobile PSA, jxzd-400 underground mobile PSA and md-350 underground mobile membrane separation unit. For the nitrogen injection fire prevention and extinguishing in the mining face, the distribution of oxidation, self heating and suffocation zones in the mining area should be measured in a timely and scientific manner, and the oxygen concentration in the autotropic zone should be reduced to less than 10 ~ 12% by nitrogen injection, so as to accelerate the transformation from the autotropic zone to the suffocation zone. In the process of implementing the natural gas fire prevention and extinguishing, comprehensive measures should be taken to reduce the air leakage in the fire prevention and extinguishing area, so as to improve the effect of natural gas fire prevention and extinguishing

2.5 prevention and control technology of gas and coal dust explosion

gas explosion and gas and coal dust explosion are still the most serious accidents in coal mines. China has established its own large-scale explosion tunnels and test bases, and carried out experimental research on the explosion mechanism, characteristics and anti explosion measures of various dusts. On the basis of experimental research on the explosion characteristics of coal dust samples from major coalfields in China, it has carried out research on the explosion characteristics under the condition of the coexistence of gas and coal dust, focusing on the problem of gas and coal dust detonated by cutting friction sparks of mining machinery, The comprehensive measures to prevent the ignition of cutting friction sparks, such as improving the structure and material of cutting teeth, are preliminarily put forward

further improve and improve the performance, hanging process and layout of passive explosion-proof water tank and water bag. The improved XGS explosion-proof water shed can also isolate the transmission of weak explosion, expand the effective range of explosion-proof (20 ~ 24m away from the explosion source) and facilitate installation and movement. Bjk-s automatic explosion suppression system can realize remote continuous monitoring of gas, coal dust concentration and deposited coal dust intensity in machine excavation face or places with explosion danger, over limit alarm and control the power failure of operation equipment; It can extinguish gas combustion, weak explosion, etc. locally, and effectively control gas and coal dust explosion. The ybw type non power triggered explosion suppression device developed in recent years adopts the photoelectric detonating cord blasting to spray water quality explosion inhibitor. The best water mist formation time is less than 150ms, and the water mist existence time is more than 500ms. It has good fog forming performance, small daily maintenance workload, and convenient installation and application

3 suggestions for coal mine safety science and technology work

as mentioned above, under the care of the party and the state, coal mine safety science and technology work has made great progress, and the gap between its overall scientific and technological level and that of foreign countries is narrowing. Compared with 10 years ago, the safety situation of coal mines has also improved greatly, but there is still a large gap with foreign countries. Compared with the mortality rate of one million tons of coal production: in recent 10 years, China's state-owned key coal mines are 1.05 ~ 1.2, and the national average (including state-owned and township coal mines) is 4.3; In the same period, it was 0.09 in the United States, 0.44 in Poland, 0.34 in Germany and 0.74 in India

there are about 70 ~ 80 major accidents in China's coal mines that kill more than 10 people every year, 85% of which occur in high