Progress and development trend of open-pit mining technology (including blasting technology) in metal mines in China

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Progress and development trend of open-pit mining technology in metal mines in China

Due to the disadvantages of difficult relocation and high cost, the research and development of large mobile crushing units has achieved rapid development. The discontinuous mining process of large foreign open-pit mines such as Mount Newman Iron ore in Australia, Landvalley copper mine in Canada, and Siarita copper and molybdenum mine in the United States also uses mobile crushing stations. In 1997, Qidashan Iron Mine of Anshan Iron and Steel Co., Ltd. built the movable belt transportation system for ore and rock in stope for the first time in China. The system has been running normally since it was put into operation, which indicates that the discontinuous mining technology of deep concave open-pit mine in China has reached the world advanced level.

[1.4 Steep Slope railway Transportation System of large deep concave open pit mine] After the open pit mine enters the deep concave mining stage, the railway transportation with a mild slope degree below 30‰ and slow working help mining mode are adopted, and the efficiency is low. With the increase of mining depth, the growth of transportation lines, and the sharp rise of transportation costs, it has become a bottleneck restricting the sustainable development of mines. To this end, during the "Tenth Five-Year Plan" period of scientific and technological research, China has successfully developed a large deep-concave open-pit steep slope railway transportation system, and realized the steep slope railway transportation mining of deep open-pit mine for the first time in China, effectively solving the technical problems of steep slope railway crawling, insufficient traction of locomotive, and safe network power supply, and successfully breaking the "bottleneck" of large deep-concave open-pit steep slope railway transportation. The results were applied to Zhujiabaobao Iron Mine of Panzhihua Iron and Steel Group, extending the railway transportation depth of 45m, mining 30 million tons of iron ore, reducing the stripping ratio of 0.42 tons/ton, increasing the iron-to-transport ratio by 20.72%, extending the mine service life of 15 years, reducing the mining cost by 25.33%, and direct economic benefits of 723 million yuan. The results were extended to Waitoushan open-pit Iron Mine of Benxi Iron and Steel Group Company, extending the railway transportation depth to 72m, saving 150 million yuan of investment, reducing mining costs by 30.43%, and direct economic benefits of 560 million yuan.

[1.5 Safe and Efficient Mining Technology of Large Deep pit open pit] Safe and efficient mining technology of large deep pit open pit is a scientific and technological achievement of the "Tenth Five-Year Plan". This research is aimed at the slope stability of deep concave open pit mine and production scheduling information management. It is the first time at home and abroad to analyze and optimize the stability of open pit slope based on the combination of modern three-dimensional numerical simulation and three-dimensional limit equilibrium analysis, which provides a scientific method for the slope design of deep concave open pit mine. Developed a real-time automated production scheduling system and management platform based on GPS positioning, realized the positioning, tracking and scheduling of personnel and equipment in the production process, realized the whole process control of the entire production system, and made it always in the optimization and efficient operation, and greatly improved the production efficiency.

In view of the three major public hazards of mine blasting (blasting dust, blasting vibration and blasting flying rocks), we independently designed and established a collection, test and analysis system for blasting dust, developed a new high-efficiency gas absorber for the first time, and determined a reasonable charging structure for micro-dust poisoning. Realizing no (low) public hazard in mine blasting. At the same time, a hydraulic charging structure and a comprehensive vibration reduction blasting technology, which reasonably arranges the detonation time sequence and time difference, and adopts the cushioning soft plug layer, greatly reduces the dust and blasting vibration, and obviously improves the blasting effect. The flying stone flexible protective net system is developed for the first time, the throwing distance of blasting flying stone is reduced by 50%, and the degree of flying stone can be controlled within 100mm. The technology as a whole is at the international advanced level.

[1.7 Key Technologies for Smooth transition from Open pit to Underground Mining] "Key Technologies for smooth transition from open pit to underground Mining" is the national "11th Five-Year Plan" science and technology research topic. This topic focuses on the key technical difficulties of mining and safety in the process of open-pit mining, such as when to transition from open-pit mine to underground mine, how to smoothly connect mine development system and open-pit underground production capacity, how to realize efficient underground mining under high and steep slope, how to prevent water inrush in open-pit to underground stope, and how to establish an early warning mechanism of open-pit slope landslide and underground surrounding rock collapse caused by mining disturbance The research is carried out and the following results are obtained: the dynamic relation function of open-pit to underground mining boundary is established, and the method of determining the reasonable time of smooth transition from open-pit to underground mining is invented; In order to ensure the safety of open-pit to underground caving mining method, a formula for calculating the thickness of overburden layer is invented, and the formation technology of ore-rock composite overburden is proposed for the first time, overcoming the safety technical problems of open-pit to underground caving mining method. Based on improving the efficiency of two-step mining from open pit to underground, the double bottom structure and its technology are invented to realize safe and efficient mining. In view of the characteristics of large and concentrated catchment moment of open pit, a new idea of building emergency middle section to prevent water inrush disaster is put forward creatively, and the construction method of emergency water silo is invented to improve the ability of preventing water inrush disaster in open pit to underground mining. For the first time in China, the domestic 30-channel microseismic monitoring network system has been established, and the safety monitoring and disaster warning system for the process of open-pit to underground mining has been constructed. The new functions of surrounding rock damage and degradation evaluation and rock mass quality analysis, microseismic monitoring data and three-dimensional stress field data integration, mine stress field background early warning and forecast visual digital scene, monitoring data remote transmission and expert consultation, mine personnel positioning and emergency rescue have been developed, which have reliably prevented mine disasters.