Safety rectification of open-pit mines

Open-pit Mine Safety Rectification

Start with stratified mining
From top to bottom, layer-by-layer mining is a fundamental principle in open-pit mining. Relevant regulations clearly define the stage height for open-pit mines under different rock types and different operation methods. However, there are still many small and medium-sized mines currently using extremely primitive, non-layered, high-stage mining methods. The stage height can be as much as several tens of meters or even hundreds of meters, which far exceeds the regulations. This is a very important reason for the continuous occurrence of major and serious accidents in open-pit mines. Implementing the top-down, layered mining method should be the primary content of the safety rectification in mines.  
Stratified mining can fundamentally change the unsafe working conditions of high-stage mining. An appropriate mining height not only reduces the possibility of production slope collapse but also, in most cases, makes the on-site situation more intuitive and clear, significantly improving the safety and other related production conditions. Adopting the stratified mining method is also conducive to promoting the mechanization process in mining operations. High-efficiency drilling, loading, transportation and other mining equipment can achieve the best performance in the appropriate stratified mining method, which is extremely beneficial for reducing mining costs. Promoting mechanized operation forms in mines and minimizing the opportunities for people to interact directly with rocks is of great significance for minimizing the occurrence of mining accidents to the greatest extent.  
Stratified mining is the most fundamental and effective solution to eliminate major production safety hazards in mining operations. The safety rectification work for open-pit mines should be carried out in a practical manner, starting from stratified mining from the top down.

Attach importance to the construction of waste rock disposal sites
In actual mining operations, the random disposal of waste rock or the improper setting of disposal sites can be observed everywhere. Mudslides caused by problems with the disposal site settings occur frequently. Therefore, the proper setting of waste rock sites is another important issue that should be highly emphasized in the safety rectification of mines.  
The main factors contributing to the formation of debris flows include soil, rocks, water, and necessary terrain conditions. In the process of mining construction, measures to prevent potential hazards from the disposal sites should start with the site selection. Not only should the conditions that may disrupt the formation of debris flows be considered and eliminated to prevent their occurrence, but also, in case of a debris flow, it should not have a significant impact on the outside world. From a safety perspective, it means that it should not endanger human safety. Therefore, when constructing disposal sites, one should first start from the terrain and geological conditions, hydrogeological conditions, engineering geological conditions, and the surrounding environment, or avoid unfavorable factors, select the most suitable site, or appropriately modify the relevant conditions to make them adapt to actual needs. During use, appropriate protective measures should be taken and management strengthened, such as setting up water diversion ditches, establishing supporting facilities like stone dams and sediment barriers, to further enhance the stability of the disposal site and prevent soil erosion and other disasters from occurring.  
For the already existing phenomenon of random dumping, during the rectification process, proactive remedial measures should be taken. While stopping the continuous dumping, depending on the on-site conditions, measures such as diverting the upper water flow, building a waste rock dam, relocating the downstream residents, or taking multiple approaches simultaneously to eliminate potential hazards should be implemented to prevent accidents from occurring.

Improve and expand the transportation system
The establishment of the transportation system for mining is crucial for maintaining the normal mining operations of the mine. A reasonable transportation plan for mining can bring about significant economic benefits. Once the transportation system for mining is determined and implemented, it is very difficult to change during production. Moreover, a well-designed transportation system for mining can provide the most fundamental guarantee for the safe production of the mine.  
The differences in on-site terrain and geological conditions, mining methods, production scale, and surrounding environment lead to variations in the mining transportation systems of mines. The optimal mining transportation plan that can adapt to the specific conditions of the mine and meet the requirements of regulations and various uses is the best plan. Currently, the mining transportation systems of open-pit mines are still mainly based on road mining and vehicle transportation. During the rectification process, the improvement of the mining transportation systems of most mines mainly focuses on how to reasonably establish uphill roads to achieve stratified mining. Under the conditions permitted by relevant regulations, it is necessary to try to make the routes the shortest, the engineering volume the smallest, and the production use the most convenient, in order to reduce rectification costs, lower production costs, ensure safety, and improve the comprehensive benefits of the mine. These are also specific issues that should be carefully considered during the rectification process. Therefore, I believe that the rectification work of mines should not only focus on determining the basic mining methods but also effectively carry out the formulation of mining transportation plans, and ensure the operability of the plans, so as not to make the rectification work a mere formality.

Reasonably determine the relevant elements
A large number of scientific research and production practices have proved that appropriate production factors are the foundation for the standardized mining of mines and the basic guarantee for safe production. The determination of elements such as the height of the production steps, the angle, the minimum width of the working platform, the minimum length of the working line, etc., as well as the layout of the production working face, are all closely related to safe production. They should be determined carefully based on the specific conditions of the mines and relevant regulations. The current situation where many mines do not pay enough attention to this and randomly set the parameters needs to be corrected during the rectification process. Otherwise, the safety hazards in the mines will still be difficult to completely eliminate.  
The rational determination of the final boundary position and the structure of the slope and bench of a mining area is not only related to current safety production, but also to the long-term stability of the slope. Generally, it is believed that the size of the bench angle at the end of mining is mainly related to the slope ratio, the physical and mechanical properties of the rock, the hydrogeological conditions, and the shape of the mine. Some also suggest that it is related to factors such as mining intensity and service life. The intention is that mines with high mining intensity and short service life can adopt a steeper slope to improve economic benefits. However, the author believes that the stability of the final slope should not only be reflected within the mining period of the mine, but should be a permanent issue. If in order to minimize the transportation of overburden during the mining period by taking a steeper bench angle, the unstable upper rock mass should still be removed after the mining work is completed to avoid leaving hidden dangers. Newly closed mines should pay sufficient attention to this during the rectification process.

Actively promote large-scale mining
By reviewing the accident situations in mines over the past few years, it can be observed that major accidents mostly occur in small-scale mines. With the development of the market economy, the continued existence of such small-scale mines not only has lost its positive significance but also increases social instability due to the frequent occurrence of accidents.  
Most small-scale mines lack both funds and technology. Their safety facilities and other aspects are far inferior to those of large and medium-sized mines. The occurrence of no accidents during production is merely a fluke and temporary. Objective laws indicate that small-scale, family-run mining operations cannot survive in the era of industrialized production. Instead, large-scale production is bound to replace them. Currently, large-scale mining has been vigorously promoted in our country, and the time is ripe.  
The large-scale mining operations in mines should, under the conditions permitted by resource and environmental protection planning, resolutely shut down those small-scale mines that waste resources, damage the environment and lack safety guarantees. At the same time, some mines with better comprehensive conditions should be selected and their advantages integrated for large-scale development. It is encouraging that the relevant departments have imposed restrictions on the minimum mining scale of mines and have promoted the rapid implementation of joint operations, mergers and reorganizations of mines. In some regions, the practice of bidding and auctioning mining rights has been piloted, and this move is bound to play a positive role in promoting the large-scale mining operations of mines.  
In the process of deepening the safety rectification of open-pit mines, it is necessary to attach great importance to the implementation of the principle of top-down and layer-by-layer mining, improve the development and transportation system, pay attention to the construction of important facilities such as waste disposal sites, reasonably determine technical elements and actively advocate and promote the joint transformation of small mines, and take the path of large-scale and standardized development, so as to achieve safe production in the essence of the mines.