Key engineering science and technology strategy for green, intelligent and sustainable development of deep metal mines in China

(3) leaching mining

Leaching mining is a technology integrating mining, beneficiation and smelting, which can be divided into three categories: in-situ drilling leaching, in-situ crushing leaching and heap leaching. This technology can directly recover metal elements in ore body through leaching solution, which can greatly reduce the workload of mining, beneficiation and smelting operations, reduce production cost, and provide a feasible way for deep low-grade ore recovery. Compared with the traditional "mining-beneficiation-smelting" process, the cost of in situ leaching can be saved by more than 30%, even up to 50%, which has important application value for deep mineral mining. In addition, the process does not produce waste rock, tailings, no excavation disturbance, almost no impact on the ground environment. This is also one of the main directions to achieve green mining technology in the future. Leaching mining technology is a borderline interdisciplinary subject, the basic theory is still weak, need to be further studied in granular seepage dynamics, multi-factor strong correlation mechanism and so on. In particular, the current process can recover too few bulk metal varieties, can only effectively recover uranium, copper and gold and other few metal minerals, need to vigorously study the leaching process and recovery technology of more metal ores.

(4) Integrated underground mining

Before the ore is lifted to the surface, pre-selection and pre-enrichment are carried out in the mine and most of the waste rock is thrown away, which can significantly reduce the amount of ore lifting and the discharge of waste rock on the surface. For deep mining, the ore is crushed and ground into pulp after pre-separation in the mine, and then transported to the surface concentrator by hydraulic pipeline. Compared with other transportation schemes, the technology has a series of advantages, such as low infrastructure investment, strong adaptability to terrain conditions, no or less land occupation, and is conducive to environmental protection.

The concentrator is built underground, the mined ore is processed underground, and then the concentrate is delivered directly to the surface. This can greatly reduce the amount of waste rock lifting, is an important way to solve the problem of lifting. The waste rock and tailings generated by mineral processing are left in the mine for gob filling, so as to realize in-situ utilization and reduce the pollution and damage to the ecological environment after discharging from the ground. In addition, there is no need to build a concentrator and tailings pond on the ground, saving the cost of land acquisition, plant construction and tailings pond management, and eliminating the root cause of various natural disasters caused by tailings ponds. Therefore, this is an important measure to give full play to the comprehensive benefits of the green and efficient development of mineral resources.

(5) Intelligent unmanned mining

Intelligent unmanned mining is the only way to deal with the deteriorating deep mining conditions and environmental conditions and to achieve the safe and efficient maximization of mineral resources development. Artificial intelligence is an important driving force for a new round of scientific and technological revolution and industrial change, accelerating the integration of artificial intelligence and mining development engineering technology to achieve intelligent unmanned mining of mineral resources is an important direction and forward-looking goal of mining development in the 21st century, and an important guarantee for the sustainable development of metal mineral resources in China.

At present, the construction of intelligent unmanned mines at home and abroad is still in the initial stage. At this stage, the core technology of unmanned mining is still the automation and intelligent control of traditional mining process and production organization management. This intelligent control is mainly achieved by on-site or remote control. Advances in information, communication and artificial intelligence will promote the development of unmanned mining with advanced detection and monitoring systems, high-speed digital communication networks, the Internet, the Internet of Things, 5G, big data, cloud computing, intelligent mining equipment and processes integrated as the main technical features. The unmanned mining equipment and control system in the advanced stage should have intelligent target recognition and perception, autonomous memory, autonomous judgment, autonomous decision-making, similar to the function of intelligent brain, and do not need to be achieved by external remote control. The new generation of advanced unmanned mining technology will certainly involve the transformation of mining technology and production process itself. In order to achieve the transition from the initial stage to the advanced stage of unmanned mining, it is completely necessary to make fundamental changes in traditional mining models, technologies, processes and management methods, including the development and innovation of a range of disruptive technologies and methods.