Types of mines

1. Scale

Mines include coal mines, metallic mines, non-metallic mines, building materials mines and chemical mines. Mine size (also called production capacity) is usually expressed in terms of annual or daily production. Annual production is the amount of ore produced by the mine each year. According to the size of the output, it is divided into three types: large, medium and small. The size of the mine scale should be commensurate with the economic and reasonable service life of the mine, only in this way can we save capital construction costs and reduce costs. In the process of mining production, mining operation not only consumes the most manpower and material resources, occupies the most funds, but also has the greatest potential to reduce mining costs. The main way to reduce mining cost is to improve labor productivity and product quality and reduce material consumption.

2. Digital mines

Canada has developed a vision plan to be realized by 2050: a mine in the remote northern region of Canada will be realized as an unmanned mine, from Sudbury through satellite control of all equipment in the mine to achieve mechanical automatic crushing and automatic cutting mining; The Finnish mining industry also announced its own intelligent mining technology program in 1992, involving 28 topics such as real-time mining process control, real-time resource management, mine information network construction, new machinery application and automatic control; Sweden has also developed a strategic plan "Grountecknik 2000" to advance towards mine automation. China University of Mining and Technology has also carried out technical development and application research in mining robot (MR), mining Geographic information system (MGIS) [1, 2], three-dimensional geoscience simulation (3DGM), mining virtual reality (MVR), mining GPS positioning and other aspects.

In July 1997, the Australian Commonwealth Science and Industry Organisation (CSIRO) developed a three-year research plan on coal exploration and mining, with an investment of $31 million, focusing on 18 specific projects in six areas: resource assessment, mining process innovation, mine gas control and utilization, automation, safety and material fine control. Among them, geological assessment and emergency response are the two most distinctive items. 1) Geological assessment: a 3D block model-based software was developed to assess the stratigraphic environment (sedimentary environment) of a mine or mining area; An interactive 3D (and 4D) software package for 3D visualization of heterogeneous data (microseismic monitoring data, neutron gamma sampling data, etc.); The rock mass deformation after mining is simulated by finite element/finite difference (FE/FD) model. 2) First aid response: Developed a personal safety positioning and monitoring system, which is composed of control devices, monitoring equipment, network lights and miners' different frequency radar transceiver unit, with wireless communication capability, and can report the location and safety status of underground miners even after underground disasters such as gas explosions; And developed a remote control unmanned ambulance called Numbat, used for emergency rescue of the wounded after the explosion.

With the application of real-time mine survey, GPS real-time navigation and remote control, GIS management and auxiliary decision making and 3DGM, some large open pit mines in the world (including Pingshuo and Huolinhe mining area in China) have been able to generate deposit models and mining plans in the office, and connect with stope equipment to form a dynamic management and remote control command system. In addition, Artificial intelligence technologies such as expert system, neural network, fuzzy logic, adaptive pattern recognition, genetic algorithm, GPS technology, parallel computing technology, radio frequency identification technology, global optimization method for rock mechanics problems and remote sensing technology have been applied in intelligent mine geological exploration and survey, intelligent mine design, intelligent mine mining, planning and control, and remote sensing of mine disasters The research field of paper has been applied.

3. Mine rescue

In the process of mine construction and production, due to complex natural conditions, poor working environment, coupled with people's understanding of the objective laws of mine disasters is not comprehensive and in-depth, sometimes paralyzed carelessness and illegal operations, illegal command, which causes the possibility of some disasters. In order to deal with mine accidents quickly and effectively, protect the life safety of workers, and reduce the loss of national resources and property, it is necessary to do a good job of rescue work in accordance with the requirements of the two "regulations" (coal mine safety regulations, coal mine rescue regulations). At the same time, it is necessary to educate employees how to actively carry out self-rescue and mutual rescue in the event of an accident.

Mine rescue team is a professional team dealing with mine fire, gas, coal dust, water, roof and other disasters, is a professional, technical organization, strict implementation of military management. Practice has proved that mine rescue teams play an important role in preventing and dealing with mine disasters and accidents.

4. Mining methods

According to the different stope management methods in the ore recovery process, the mining methods of non-coal mining mines can be divided into four categories:

(1) Open stope mining method is characterized by the fact that in the mining process, the goaf mainly relies on temporary or permanent residual pillars to support, and the goaf is always empty, which is generally used when the ore and surrounding rock are stable.

(2) The caving mining method is characterized by the planned use of the overlying rock layer of the caving ore body and the rocks of the upper and lower wall to fill the goaf with the ore extraction to control the ground pressure in the mining area. Generally, it is used under the condition that the surrounding rock of the ore body is unstable and the surface allows subsidence.

(3) The filling mining method is characterized by the support of the goaf by the filling material within the goaf during mining. This method can effectively maintain the gob, the stability of the surrounding rock is not high, but the production cost is high. It is mainly used for mining high ore value, sufficient filling materials, the surface does not allow subsidence and the geological conditions are particularly complex.

(4) The retention mining method is characterized by the temporary retention of part of the mined ore in the goaf during the mining process, so as to support the goaf with pillars and maintain sufficient mining space. Generally, the ore is stable, and is not easy to oxidize, bond and spontaneous combustion, and the surrounding rock of the ore body is moderately stable.

5. Current status

1. Small scale of mine investment and low mining capacity

The main body of mine investment is not enough to understand the scale of stone mine investment, do not have the investment consciousness of scale mine, performance in the mine construction has no long-term plan, geological work blank, mining plan is not clear, mining methods are backward, mining equipment and lifting equipment is simple, the annual mining volume is only a few hundred cubic meters, at most thousands of cubic meters, mining production has no plan at all. Not to mention mass production.

There is no threshold limit on the scale of investment in the stone mining industry, resulting in the proliferation of small mines across the country. Small-scale mines are often in a major stone producing area in large numbers, scattered, large ore bodies are divided into small ore bodies, complete stone deposits are divided into seven and a half, mining riddled with holes, the destruction and waste of resources is very serious.

Due to the small area of mining activities (the smallest is several hundred square meters), adjacent mines affect each other, resulting in frequent conflicts between mining enterprises, casualties occur from time to time, increasing the difficulty of mining management.

2. Insufficient emphasis on technology

Prior to this, because there is no technical threshold for stone mines in China, the genetic types and geological structures of stone deposits are diverse, and the investment subjects of mining enterprises are mostly individual or private enterprises, unwilling to spend money on geological exploration and mining design, subjectively believing that stone mining is blasting stone, there is no higher technical content in it. The weight of science and technology in quarrying activities is despised, so that the actual problems encountered in the mining process are at a loss.

Although this kind of mine in the capital investment side is larger than the previous situation, but in the overall mining plan of the mine, the determination of mining force method, the rational purchase of mining equipment are lack of unified guiding ideology, lack of scientific basis.

There are many mines with an investment scale of more than 10 million yuan, or even tens of millions of investment. Due to unclear geological conditions, unclear occurrence and occurrence conditions of ore bodies, lack of reasonable economic and technical evaluation of mines, lack of mining design scheme, mine investment has great blindness and great risks. The determination of the first mining area, the layout of the mining face, stripping and slagging, transportation and stacking sites are not clearly designed, and the whole mining area is very disorderly. Due to the uncertainty of the first mining area, the mining production has great blindness, and even the thickness of the fracture zone and regolith is not clear. Once the mining progresses to the expected depth in the mind, the thought will be shaken, and even stop working in this mining face, and find another site to start over. A shot to change a place, always stay on the surface of the mining area, all the surface of the mining area have been mined again without finding a lot of further mining, wasting a lot of manpower, financial and material resources, as well as precious time. What is more terrible is that so much power has been invested, and there is no clear route, because the activities carried out in the front lack purpose, the corresponding data lack reference value, and can not produce great guiding significance for the future work.

3. Lack of professional and technical personnel

After years of development, on the basis of many small and medium-sized enterprises, China has formed a large stone enterprise group, these large enterprises pay more and more attention to the development of stone resources, and the investment in resource prospecting and mine construction is also increasing.

There is generally a mineral development department in the enterprise, but there is a lack of professional personnel engaged in this area, and there is a lack of experienced and capable personnel. Many enterprises engaged in mine management and technology personnel are not geological and mining professional background, lack of basic knowledge of these professional, it is difficult to have outstanding achievements in mining technology.

Often see or accept the commission of some stone companies to recruit engineers or miners with practical experience, technicians, but meet the conditions are very few, few candidates. Fresh graduates have to go through several years of practice to take up the responsibility, and the new graduates engaged in the hard work of the mine, its own in the mind and will also need to hone, willing to bear hardships and dedication to be cultivated, wages should also be reasonable, otherwise it is difficult to retain talent.

Enterprises can not recruit talents, the lack of professional and technical force, in the development of resources and mining is equal to the lack of strong technical support.

On the other hand, we have a state-owned professional geological team and mine design units, such a professional team is the backbone of the development of China's stone mining industry. However, over the years, it seems that the role of these professional departments in the stone industry is getting smaller and smaller, the stone exploration projects of the geological team of building materials are few and far between, and the design projects of stone mines are even less. One reason is that the mining enterprises do not pay attention to the basic work in this area, another reason is that these professional teams have less contact with our stone enterprises, and the publicity in the industry is not enough, and the enterprises do not understand our professional departments, or even do not know. It also shows that these professional departments should increase market development efforts, improve the awareness of serving the stone industry, actively contact the majority of stone enterprises, understand the needs of enterprises, and do a good job for enterprises.

4. Conservative ideas interfere with mine development

Since the stone mining industry, the mining technology used in stone mining in China has been explored by the domestic itself, and some are also invented by the Chinese. Such as burning granite for digging quasi-ditch, using black powder for single-side splitting blasting, using hammer and piano chiselling to separate the bulk of marble mother rock, etc., are the crystallization of the wisdom of our working people, in a specific historical period, these mining methods still played a considerable role, laying the foundation for the mining of stone.

In the 1980s, China implemented the policy of reform and opening up, the stone industry has been unprecedented development, Italy, Germany, the Netherlands and other countries of advanced mining and processing technology has been gradually introduced, has imported mining and processing of complete sets of equipment has nearly 300, there are more than 10 domestic enterprises to produce stone mining special equipment, It has played a due role in promoting the development of the national stone industry.

Diamond beaded saw was introduced in the 1980s, but because most of the domestic mines do not have the conditions for use, coupled with the supporting consumption of materials are expensive, in fact, these imported beaded saws and supporting other mining equipment are idle, did not play the role of equipment.

Mines adopt more advanced mining technology, it is necessary to spend money to purchase the necessary mining equipment, mine investment compared with the original mining method to much more, mining enterprises in the early stage of mine construction ideological preparation is insufficient, and the understanding of new mining technology is not comprehensive, reluctant to take risks, conservative ideas prevail, the promotion of new technology faced with difficulties and resistance is not difficult to imagine. The profit-oriented concept of "heavy processing, light mining" seriously interfered with the development of mining industry at that time.

5. Enterprises are misled and have no clear concept of practical mining technology

The key link of stone mining is the separation of the mother rock of the large rock mass, whether by controlled blasting method, or by mechanical sawing, flame cutting, mechanical splitting and other means, the purpose is to separate the complete specifications of the block from the bedrock. This is also a mine core technology, once this step of technical problems have been broken through, other follow-up work is relatively simple and much easier.

In recent years, some new mining methods and equipment have been popularized and applied, and good results have been received. Such as hole grooving blasting splitting technology, hydraulic splitting technology, detonating cable row hole control blasting technology, flame cutting technology, burst pipe control blasting technology, static (expansion agent) expansion technology, black powder pot pre-cracking technology, diamond beaded rope sawing and circular saw cutting, etc., have different roles and effects in different stages of mining technology.

These mining technologies have their own advantages and disadvantages. In the case of understanding the principle of each technology and the performance of equipment and materials, combined with the actual situation of the mining area, the analysis of which technology is suitable for mining, and then optimize the combination, and finally determine the mining process and mining method applicable to the mine. It should be clear that for a mine mining, the use of a single mining method for production, from the technical and economic evaluation is not the best program, only different rocks, different geological conditions, different stages, with different combinations, is the most reasonable and most economic. The speed of the detonating cable is fast, but the blasting of two non-free surfaces at most, and the blasting of more than three free surfaces is not successful. The success of sawing with beaded saw is high, but the cost of single-side sawing is compared with blasting and flame cutting. The cost of single-side sawing is greater than that of black powder controlled blasting and hole grooving blasting. It is an indisputable fact that the cost of hole grooving blasting is low, but it can not complete the blasting of more than two free planes at the same time (at least not yet). Therefore, each method is not a panacea, although it can be done at the technical level, but the economic aspect should also be considered.

Some equipment manufacturers or technology holders, in the promotion of enterprises, blindly exaggerate the role of the technology, exaggerate the function of the equipment, this promotion with a certain exclusion, it seems that only this technology, this equipment can solve all the mining problems on the mine, other technology and equipment are not applicable, and even other technical equipment said nothing. Until you sell your stuff and make a profit. As for the applicability of the equipment after the use of problems in the process, it takes a perfunctory attitude, so that enterprises suffer losses. What is more, the theories and methods used for mining other kinds of minerals are transferred to stone mining without proof, spending hundreds of thousands or even millions of funds, making big explosions, blowing down a mountain or half the wall of the mountain at a time, and then searching for larger rocks in the rubble pile. Such a blast of the mountain volume of hundreds of thousands or even millions of cubic meters, and can use the block sorted out less than a few thousand cubic meters of waste, waste rate is extremely low, the waste of resources is extremely serious. There are also hidden cracks in the raw materials, and the rate of sheet metal production is reduced during processing, and the adverse effects caused by a blasting are very serious