The coal in Helan Mountain burned for 300 years and lost tens of billions. Cann't you put it out with water?

This is a scar! 202 1 Helanshan coal mine burning incident once again triggered a heated discussion. A fire has spontaneously ignited for more than 300 years and has not been extinguished. In addition, Taixi coal burned in the fire area every year is about1150,000 tons, and the direct economic loss is about 10 billion yuan, with a total loss of tens of billions. It can really make people feel distressed. Many people say why not. What I want to say is that if there is a way to put it out, it can be used, and it will not be left untreated for more than 300 years.

This can only explain one problem, that is, there is no way to put it out. It's hard to put out, so I don't want to. Maybe there is really no way. Can't water put it out? Let's take a look at the situation.

How badly is Helan Mountain burned? Helan Mountain is located at the junction of Ningxia Hui Autonomous Region and Inner Mongolia Autonomous Region. It is not only the main wildlife living area in China, but also the main mineral distribution area in China. According to public information, there are 665 species of Picea crassifolia, Populus davidiana, Betula platyphylla and more than 80 species of animals/kloc-0, which is very rich.

There are more minerals. The whole Helan Mountain-mountainous area is rich in high-quality coal, including Shizuishan and other large-scale mining areas 10, as well as phospholimestone, sandstone, limestone, clay rock and other minerals, including one of the "five treasures" in Ningxia, all of which are produced in this area. And when we see Helan Mountain burning, we are bound to be very worried. If the fire is not controlled, there may be fewer wild animals and plants in these areas in the future, so it is normal for everyone to ask if the fire in this area can be put out.

However, it doesn't mean that you won't go out after you let it out. The burning is very intense. According to statistics, only within 28 square kilometers of Rujigou mining area, there are 25 fire areas, five of which are in nature reserves. The area burned by the fire has exceeded 3.3 square kilometers, and the deepest part is 280 meters. It is observed that the burning fire in this area continues to spread, spreading to the surrounding area at the speed of14m to16m every year.

Unfortunately, the proven reserves of the highest quality Taixi coal in the whole region are 580 million tons, with only about 270 million tons left. The fire is still affecting the area. So according to this trend, these high-quality coals will not be seen in the future. According to the forecast data of fire development trend, Taixi coal held by Rujigou mining area may be burned out in 50 years. Now everyone knows how badly Helan Mountain burns coal. We see that the coal in this area is disappearing bit by bit.

How is the coal seam in Helan Mountain burned? As mentioned above, Helan Mountain is rich in coal, which is the main coal producing area in China, so there are countless coal enterprises and workshops, large and small. According to public data, in the 1990s, small and medium-sized coal mines in Helan Mountain area were mined everywhere, and there was no scientific management method, which was mostly caused by workers heating underground or ground fires not being extinguished. As a result, the fire continued to burn for hundreds of years, while the old fire area became more and more fierce, and new fire areas were constantly produced, which also triggered the emergence of chain effects.

So, to put it simply, it was brought by our own coal mining. However, due to the characteristics of coal in this area, such as the high metamorphic degree and high gas content of Taixi coal, not only the coal is burning, but also a large amount of gas is released to participate in the combustion, which accelerates the combustion speed in the fire area. As a result, the situation was "out of control". Another great feature is that the coal seams in this area are very deep.

The heat generated by combustion is also so huge that it is difficult for anyone to get close to the fire area directly. According to the temperature that the human body can bear, the high temperature of about 60 degrees may be unbearable. The burning of a large amount of coal may obviously feel the baking of the fire within a few meters or even dozens of meters, so the impact is very great.

Then why not water it? Indeed, when coal is burned on a large scale, the pollution brought to us is also very great. According to the data, only 1.29 million tons and 5,324 tons are emitted each year when burning in the fire area, which is equivalent to 269 times and 24 times that of a medium-sized thermal power plant respectively. So everyone wants to release such data, but can it be done? It's hard to do. First of all, under natural conditions, if you say that the whole Helan Mountain hasn't rained for more than 300 years, it must be nonsense.

The heavy rain can't be put out, can it be put out with water? Obviously impossible. The main reason is that the coal seam in Helan Mountain is very deep. Even if we douse the fire on the surface with water, the deep coal combustion may have been completely absorbed before it touches the water source. As a result, after the fire is baked, the fire below will cause the carbon on the surface to burn continuously and cannot be extinguished at all.

There is absolutely no way to douse it with water. Scientists must have considered it a long time ago. If it was feasible, it would have been implemented long ago, so it is obviously not feasible. Strictly speaking, there is no good fire extinguishing method, so it is still burning. This is the general situation.

1, Taixi Wujin 2, a fire that lasted for more than 300 years, but a strange sight appeared in Rujigou, Helan Mountain. At night, the whole mountain is red. If you come closer, you can even see the inside of the mountain through the rocks, just like a burning boiler furnace!

It turns out that the coal in Helan Mountain is burning! This kind of combustion is called spontaneous combustion of coal seam in industry.

3. The harm of underground coal fire. Can water put out underground coal fires? 5. Coal spontaneous combustion is a worldwide problem. 6. At present, the control measures are as follows: First, with the help of Beidou positioning and remote sensing technology, draw the underground coal fire distribution map, understand the scope of the fire area, establish a regional monitoring system for coal seam spontaneous combustion, and detect the progress and situation of the disaster at any time, so as to facilitate the timely organization of personnel to carry out disaster relief activities.

Fire fighting and development can be combined, and whoever puts out the fire and develops it (including coal mine infrastructure transportation) is suitable. The fire area can be divided into dozens of pieces and handed over to private enterprises for fire fighting and development within a time limit! The state gives all kinds of preferential support! Better than burning it for nothing!

Helan Mountain is a famous mountain located at the junction of Ningxia Hui Autonomous Region and Inner Mongolia Autonomous Region in China. It is located in the west of Ordos Basin, bordering Ordos Plateau and Yellow River Hetao Plain in the east, with an average elevation of about 2,500 meters. Helan Mountain is an important geographical dividing line in northwest China and an important climate dividing line in China. Because of the blocking of mountains, on the one hand, it blocks the cold airflow in Mongolia and Siberia, on the other hand, it also blocks the humid southeast monsoon, so it is not only the dividing line between the monsoon region and the non-monsoon region in China, but also the dividing line between the annual precipitation line of 400 mm in China and the grasslands and deserts in China.

Geologically, Helan Mountain is located at the junction of East Asian continental main plate, Ordos fault block and Helan Mountain-Hengshanbao fault zone. The magma layer is not fully developed, and geological disasters such as volcanic eruption rarely occur here since ancient times, so the geological sedimentation is obvious, creating a rare environment for the deposition and development of metal deposits such as coal.

Judging from the coal reserves in this area, the long-term theory can reach 1 1 100 million tons, and the proven coal has exceeded 3 billion tons. Although compared with several major coal producing areas in China, the ranking of coal reserves in Helan Mountain is not very high, it is precisely because of the superior sedimentary conditions in this area that the quality of coal is much higher, especially Taixi coal, which is famous for its low impurities, high calorific value and compact structure. However, in such a high-quality coal producing area, there has been a thorny problem for a long time, that is, coal seams in some areas continue to burn, losing tens of billions of yuan every year. Why not try to put out the fire?

Speaking of which, everyone should be impressed by the world-famous "Hell's Gate". Since exploration in 1970s, the former Soviet Union has conducted a lot of drilling in this area to obtain abundant natural gas resources. Who would have thought that during drilling, the gas field collapsed violently and a large amount of natural gas was released. In order to avoid uncontrollable gas explosion, scientists ignited the gas, but no one thought it would catch fire.

Coal seam burning and other events are not limited to Helan Mountain, but also famous: Cherya coalfield in India has been burning for more than 100 years, and Tielek coalfield in Xinjiang, China has also been burning for 50 years. The underground coal area located next to a highway in Australia, although small in scale and small in fire, has been burning in obscurity for thousands of years. Why include coalfields and gas fields like Helanshan coalfield, and why the coal seam fire has not been extinguished for so many years?

As we all know, the combustion of substances must meet three basic conditions, namely, combustibles, combustion improvers and reaching the ignition point. For coal seams, combustible materials are pulverized coal or smaller particles. When the materials with good coal quality and capable of being ignited are piled up to a certain scale, it provides a material basis for combustion.

For the combustion improver, that is, oxygen, if there are many pores or cracks in the coal seam, which can keep air circulation with the outside world, then oxygen will have an effective source and will be fully supplemented in the combustion process. For the ignition point, when the heat released by the interaction between coal seam and oxygen is effectively accumulated, it will promote the temperature rise of coal seam in a larger area. Once the ignition point of coal (about 300 degrees Celsius) is broken, large-scale combustion can be "a single spark can start a prairie fire".

And in the process of coal development, there is a greater opportunity to increase the superposition effect of the above three factors. On the one hand, human mining activities will undoubtedly destroy the original structure of coal seam, which will not only produce more fragments and broken pulverized coal, but also make more air circulate into coal seam. On the other hand, in the process of coal mining, open flames sometimes occur due to improper operation or circuit failure. Firstly, the coalbed methane located in the upper part of the coal seam is ignited, and then on the basis of material and oxygen conditions, the coal seam is gradually promoted to burn in a wider range and for a longer time.

At present, the burning area of Helanshan coal mine is mainly concentrated in Rujigou mining area. Everyone must be thinking, why not use water to put it out? Although the annual precipitation here is not very large, there are sometimes short-term heavy precipitation in the summer rainy season every year. This weather condition can't even put out the fire in the coal seam, let alone artificially pump it. I think it is difficult to put out with water for several reasons:

One is that water and high-temperature coal will react chemically, and the substances produced are carbon monoxide and hydrogen, both of which are less dense than air and belong to combustible gases. Once sprinkling water on the burning coal seam, a large amount of combustible gas will gather on the upper surface of the coal in a short time, which will lead to more intense combustion and release more heat. Instead of extinguishing the burning coal, it intensified the burning of the coal seam, and maybe there will be a violent explosion.

The second is that the combustion of coal seam has a "three-dimensional" effect, that is, it is not simply burning at the depth level. What we see on the surface of the earth is only the different manifestations of burning at different depths. We only see it because it is exposed on the surface. In fact, the lower coal seams with different depths may also form combustion phenomena or have a basis for combustion. Therefore, if water is used, it can only affect the burning coal seam on the surface. Here, the factor that watering releases more combustible gas is ruled out. Even if a large amount of water is sprayed to control the surface fire source, liquid water will be converted into steam under the action of high temperature, and it is difficult to go deep into the coal seam. Once the liquid water can't keep up, the heat released by the lower combustion will ignite the upper coal seam before long. This is one of the reasons why it is difficult to put out even if it rains heavily.

Third, the burning coverage of coal seam is very wide, even if we see the fire on the ground, it is far from the complete burning of coal seam. The underground connected "combustion channel" will produce different results because of the different coal seam structure, coal content and heat release, so it is very complicated, and it is difficult for us to judge the fire direction and combustion distribution of deep coal seam. Therefore, pouring a fire source on the surface is tantamount to "looking at a leopard in a tube."

Therefore, for the control of small coal mine fires, it is generally chosen to reduce the air circulation and the degree of contact with air, such as injecting a large amount of nitrogen or nonflammable foam into the coal seam, or injecting a large amount of passivation gel to reduce the area and degree of contact between coal and oxygen, so as to achieve the purpose of "taking the bottom out of the jar". But even if this method is applied, even in small coal mines, the cost is extremely high, which needs continuous monitoring and in-depth implementation. Once the fire in any area is not controlled, it will soon spread again.

For a large coal mine like Helan Mountain, the cost of applying the above-mentioned "permanent cure" scheme will be higher, which is bound to be a long process and cannot guarantee 100% success. All the material inputs and labor costs together may be far higher than the actual economic value of the coal burned, which is not worth the candle. It is impossible to start until a comprehensive and economical measure is found.

Speaking of Taixi coal, friends who are familiar with coal must know it very well. It is high-quality anthracite produced in Rujigou mining area, Shizuishan City, Ningxia Hui Autonomous Region. Its three lows (low phosphorus, low ash and low sulfur) and six highs (high calorific value, high lump coal rate, high specific resistance, high chemical activity, high clean coal recovery rate and high mechanical strength) are world-renowned.

Photography in Rujigou Mining Area: Western Phenomenon

However, in the mining area where this kind of high-quality coal is produced, there are many areas where smoke and dust are lingering. Local friends all know that it is the spontaneous combustion area of Rujigou Coal Mine. Burning high-quality Taixi coal in vain every year is about11500,000 tons, and the direct economic loss is about 10 billion yuan.

Photography in Rujigou Mining Area: Western Phenomenon

How serious is the coal seam fire in Rujigou mining area? In Rujigou mining area, many hills look like Danxia landform, layered with many colors, much like Melaleuca cake, but the staff in the mining area will definitely warn, so they can only look from a distance and can't get close.

In Rujigou mining area, a mountain with an altitude of about130m seems to be Danxia landform after spontaneous combustion. Reporter Liu haishe.

Because this is a completely burned "coal ash" mountain, the mountain is loose, a little trouble will drop a lot of sand and stones, which will easily lead to landslides, so don't approach these areas to avoid danger.

The mountain has collapsed due to spontaneous combustion of coal seam.

In Rujigou Coal Mine, there are many smoking areas, one in the east and one in the west. Even in the big stone area, you can see the raging underground fire. Of course, these mountains are off-limits for human beings, if you don't want to be grilled fish! It's really like the flaming mountain in Journey to the West.

How many areas have fires in Rujigou mining area?

Rujigou Mining Area is mainly composed of five pairs of mines, such as Rujigou Coal Mine and Baijigou Coal Mine, with a total production capacity of 4.6 million tons/year. Of the 25 fire areas in the mining area, 5 have been extinguished and 4 have not been completely extinguished, and 16 is spreading rapidly.

Among them, Erdaoling fire area in Helanshan Nature Reserve is expanding, and it is connected with Erdaoling fire area in Alashan Zuo Qi, Inner Mongolia. What's more, some areas have obviously been put out, but soon smoke and dust emerged, which shows that the underground fire is still spreading.

Yang Ya Mining Area of Dafeng Coal Mine is the largest fire area in Rujigou Mining Area. It is the second and last coal seam of Taixi Coal, but there is an unpleasant smell in the air. It is estimated that the fire area here has burned 350,000 tons of Taixi coal. In 2020, the coal mining capacity in Rujigou mining area is about 6.5438+0.6 million tons, but the whole mining area burns 6.5438+0.65438+0.5 million tons of coal every year.

At this rate, it is estimated that there will be no coal recoverable in Rujigou mining area in another 50 years. Of course, the lack of coal is only one problem, and the other is the astronomical pollution that destroys the land.

In March 2020, the Autonomous Region Ecological Environment Monitoring Center conducted on-site monitoring of the atmospheric environment in the spontaneous combustion fire area of Rujigou mining area, and found that the annual emission of particulate matter in the fire area was as high as 1.29 million tons, and the sulfur dioxide was 5324 tons.

The other is the impact on the ground. The natural high temperature of underground coal mines is released through the ground, which will lead to the rise of ground temperature, the exhaustion of land and the withering and death of plants. At present, the damaged land in the fire area has reached 332 hectares, and the wild animals living on the land are seriously threatened.

Why not put out the fire? Can't you water it? Coal mine fire is a puzzling problem, because most coal seams are underground, even if the open-pit coal seams are outcrops, how can underground coal seams burn? Why does it keep burning? Where does the oxygen for combustion come from?

The first question should be difficult to answer, because the Rujigou coal mine fire first started in the Qing Dynasty more than 300 years ago. The biggest possibility is that miners forget to put out the fire or the fire spreads when they are heating underground. At present, among the more than 20 fires burning in Rujigou mining area, some started in the open air and burned underground, while others have been spreading.

For more than 300 years, Rujigou has burned countless coals, and the total loss may be as high as tens of billions. The exact figure may be difficult to estimate.

Why does the underground coal seam keep burning?

This problem may be difficult to understand, but because of the existence of open-pit coal seams and underground tunnels, oxygen supply channels have always existed, and because of the complex internal structure of the mountain, these channels may be very hidden.

The above picture shows the smoke and dust emission from underground coal seams and oxygen supply channels. Everyone can see the smoke emission, but there are various sources of oxygen supply channels. The other is that the open-pit coal seam burns underground:

For example, lightning or forest fire causes coal seam fire, the open-pit coal seam slowly burns to the inside, and oxygen supplement enters from the loose coal ash layer that was initially burned. In the end, the whole mountain may be burned loose, causing collapse or even collapse.

How to put out the fire? Is it okay to water?

Of course, the fire is watered, and the coal seam fire is underground. Isn't it right to mix water? If we can have the technology of flooding Jinshan, it is obviously possible, but the burning area of coal seam is high and low, which is obviously unreliable. What should we do?

If it happens at the beginning of the fire, the treatment method is actually very simple. Generally, the fire point can be dug out and isolated, but in the middle and late stage, things are more difficult, because it is completely underground, and its oxygen supply channel is difficult to find out. Direct water injection will not help!

Then we can only investigate its air supply channel, and then put out the fire by grouting. The most effective way is to inject mud into the ground with a high-pressure pump to block its air supply channel, and the remaining coal seam fire will slowly go out. However, due to the complexity of underground fire path and high fire extinguishing cost, many coal mines let it burn directly, such as the famous "Flame Mountain" near Wenggen Mountain in Australia, which has become a tourist attraction.

In addition, because coal is illegally mined or excavated in the fire area and oxygen is injected into the fire-extinguishing coal seam again, it may be rekindled, or air passages may be added for other geological changes to form a fire again, so extinguishing coal seam fires is a long-term project.

Fire protection in Rujigou mining area

Taixi coal has good coal quality, high chemical activity and high gas content. Therefore, not only coal but also gas (coalbed methane) is burned in the coal seam fire, so the fire area spreads quickly.

Rujigou mining area has a large burning area and a wide distribution range. At present, stripping and grouting are adopted, and targeted measures are taken in combination with the current situation, technology and economy of each fire point. At present, grouting and grouting technology must be used to extinguish the fire in 9 fire areas in Baijigou coalfield and 5 fire areas in Helanshan Nature Reserve.

However, in six fire areas, such as Cao Zhong fire area and Yang Ya fire area, due to the large accumulated energy, sufficient air leakage and oxygen supply, large dip angle of coal seam and large open flame, the shallow fire area was put out by stripping grouting.

In fact, stripping is to mine some exploitable coal seams and cut off the fire source, but this will be accompanied by another result, such as increasing oxygen supply channels and illegal mining under the banner of fire fighting. Therefore, to complete the fire fighting scheme in Rujigou mining area, scientific overall planning is needed.

Is it possible to drill a hole around the fire and pump out the gas from the coal seam? The fire can burn for so many years, which proves that coal contains a lot of high-concentration gas. After high-concentration gas drainage, high-pressure water can be injected into the borehole, which can increase the water content of the coal seam on the one hand, and increase the gas drainage volume of other boreholes on the other. The burning coal yard is not filled with gas, so the fire can be extinguished slowly. I wonder if this method is feasible. Personally, don't spray if you don't like it.

There must be a way. I said, get a wind shield to stop the sandstorm and let all the sand from the sandstorm fall into the coal area to put out the fire.

Firstly, the range of underground fire point was found out by ground exploration equipment, then gas was extracted from a circle of holes in the periphery and high-pressure water was injected, and the intermediate fire point was gradually extinguished underground by using a 100-meter long-arm engineering vehicle with a high-pressure water gun.

There are many exposed coal seams in Helan Mountain. As long as the temperature reaches a certain level, spontaneous combustion will occur (there is no oxygen under the surface, but the opposite is true on the surface), which can be put out with water, but spontaneous combustion occurs randomly in such a wide area. So it is too difficult to completely control and govern.

This combustion is very good for the following reasons:

1, coal is the first evil of the earth's temperature rise and environmental deterioration, and it can no longer be used; The whole world has realized that in the middle of this century, coal will be replaced by clean energy to achieve the goal of carbon peak and carbon neutrality. Therefore, it is better to burn these coals as soon as possible.

2. The burning of these coals is not mainly because of the coal itself, but because of the natural gas released from the coal. The continuous release of these natural gases leads to the continuous burning of coal. If these natural gases are not burned, it is easy to cause environmental pollution and even explosion in the air. Through incineration, the problem of environmental pollution can be effectively solved and the life safety of people around can be guaranteed.