Intelligent Mining Technology for an Underground Metal Mine Based on Unmanned Equipment

Intelligent Mining Technology for an Underground Metal Mine Based on Unmanned Equipment

  Intelligent Mining Technology for an Underground Metal Mine Based on Unmanned Equipment


    This article presents facts and figures on mining equipment safety and reviews various important aspects of mining equipment safety including quarry accidents, electrical accidents, equipment fires, maintenance-related mining accidents, causes of mining equipment accidents and major ignition sources for mining equipment fires. A number of methods considered useful for performing mining equipment safety analysis are also presented. Useful strategies to reduce mining equipment fires and injuries, guidelines to improve electrical safety in the mining industry, and human-factor-related tips for safer mining equipment are discussed.


   



    This article analyzes the current research status and development trend of intelligent technologies for underground metal mines in China, where such technologies are under development for use to develop mineral resources in a safe, efficient, and environmentally friendly manner. We analyze and summarize the research status of underground metal mining technology at home and abroad, including some specific examples of equipment, technology, and applications. We introduce the latest equipment and technologies with independent intellectual property rights for unmanned mining, including intelligent and unmanned control technologies for rock-drilling jumbos, down-the-hole (DTH) drills, underground scrapers, underground mining trucks, and underground charging vehicles. Three basic platforms are used for intelligent and unmanned mining: the positioning and navigation platform, information-acquisition and communication platform, and scheduling and control platform. Unmanned equipment was tested in the Fankou Lead-Zinc Mine in China, and industrial tests on the basic platforms of intelligent and unmanned mining were carried out in the mine. The experiment focused on the intelligent scraper, which can achieve autonomous intelligent driving by relying on a wireless communication system, location and navigation system, and data-acquisition system. These industrial experiments indicate that the technology is feasible. The results show that unmanned mining can promote mining technology in China to an intelligent level and can enhance the core competitive ability of China’s mining industry.


   



    With the world’s rapid economic development, the demand for mineral resources is increasing. It has been forecast that the depth of more than 33% of the metal mines in China will reach or exceed 1000?m within the next decade. Deep underground mining will become the trend of metal mining in China [1]. To overcome the disadvantages of traditional mining methods, such as excessive resource consumption, poor operating environments, low production efficiency, high safety risks, high production costs, and severe pollution, it is essential to develop an intelligent mining technology for underground metal mines that provides complete safety, environmental protection, and efficiency [2], [3]. Some developed countries have done a great deal of work in the field of intelligent mining for underground metal mines over many years, and thus have considerable experience in this field. At the beginning of the 21st century, Canada, Finland, Sweden, and other developed countries made plans for intelligent and unmanned mining. At the Stobie Mine, an underground mine belonging to the International Nickel Company of Canada, Ltd. and a typical example of such an automated mine, mobile devices such as scrapers, rock drills, and underground mining trucks are operated remotely and workers can operate the equipment directly from the central control room on the surface [4]. According to the Canadian government’s 2050 long-range plan, Canada intends to transform one of its underground mines in the northern part of the country into an unmanned mine. The plan states that all devices will be controlled from Sudbury via satellite in order to achieve intelligent and unmanned mining. Another intelligent mining program covering 28 topics—including the real-time process control of mining, real-time management of resources, construction of a mine information network, and application of new technology and automatic control—was carried out in Finland. Sweden has developed the Grountecknik 2000 strategic plan for mine automation [5], [6], [7], and veteran mining equipment companies such as Atlas Copco are actively developing a series of unmanned underground gold mining equipment and related control systems that can be used to implement the strategic plan. One of the most famous institutes in unmanned vehicles, the Commonwealth Scientific and Industrial Research Organization of Australia, is making great efforts to achieve the intelligent mining of underground mines, with a particular focus on the unmanned control of various types of equipment [8].


   



    Although these developed countries have already invested a considerable amount of time and money into the study of intelligent mining, only a few related studies have been carried out in China, especially in the field of intelligent equipment and platforms. In order to rapidly advance its intelligent mining capabilities, China is supporting many intelligent mining projects, including the Key Technology and Software Development for Digital Mining project and the High-Precision Positioning for Underground Unmanned Mining Equipment and Intelligent Unmanned Scraper Model Research project. In particular, a project titled Intelligent Mining Technology for Underground Metal Mines was established during the 12th Five-Year Plan, in order to promote intelligent mining technology to a certain extent. This article introduces several research achievements and their applications in this project. Trackless mining equipment such as rock-drilling jumbos, down-the-hole (DTH) drills, underground scrapers, underground mining trucks, and underground charging vehicles have been developed using intelligent technologies. Suitable communication techniques, sensors, artificial intelligence, virtual reality, information technology, and computer technology for mining equipment and platforms have been implemented. The experimental results indicate that some of the system’s functionalities are innovative and show good performance.


   



    2. Intelligent mining


    Mining is one of the oldest industries in the world. environmental protection equipment techniques have passed through a rapid change from artificial production, mechanized production, and on-site remote-control production, to intelligent and fully automated production. In order to move the mining industry forward, mechanization tools have been developed, single-equipment and independent systems have been automated, and the entire mining production process has been highly automated [9]. By integrating information technology with the industrialization of mining technology, intelligent mining technology has been rapidly developed, based on mechanized and automated mining, as shown in Fig. 1. This has resulted in the gradual upgrading of intelligent processes in mining equipment; unmanned and centralized mining equipment have now entered the stage of practical application, which will significantly advance the automation and information technology used in mining [10].


   



    Integrated communication, sensors, artificial intelligence, virtual reality, information technologies, computer technologies, and unmanned control equipment were combined in order to achieve intelligent mining technologies, as shown in Fig. 2. Such technologies are based on precise, reliable, and accurate decision-making and production process management through real-time monitoring; they allow mine production to be maintained at the optimum level, and lead to improved mining efficiency and economic benefits. In this way, green, safe, and efficient mining can be achieved.


    Taking a typical trackless mining technology as an example, intelligent mining technology can be divided into three layers—the control layer, transport layer, and executive layer [11].


   



    As shown in Fig. 3, the executive layer mainly consists of trackless mining equipment such as rock-drilling jumbos, DTH drills, underground scrapers, underground mining trucks, or underground charging vehicles. The transport layer mainly includes a ubiquitous information-acquisition system, wireless communication system, and precise positioning and intelligent navigation system. The control layer is designed as a system-level platform, and is responsible for intelligent mining process scheduling and control. This is the core of the entire system, because all intelligent mining-related functions and control ideas are implemented through this platform. First, a reasonable gold and diamond mining equipment plan is designed by analyzing the reserves of mine resources and geological conditions in combination with the underground production schedule. Next, an intelligent scheduling and control platform is developed. Control instructions for the equipment are sent through the transport layer to a specific piece of equipment in order to perform a mining task at a specific position and time. Within the executive layer, the control layer collects current information on the tunnel and basic information about the vehicle in real time; this information can be used to determine the location of the equipment or adjust it at any time until that entire stage of the mining plan is successfully completed.


   



    Intelligent trackless mining technology is based on intelligent unmanned equipment at the executive layer, such as rock-drilling jumbos, DTH drills, underground scrapers, underground mining trucks, or underground charging vehicles. The functions of intelligent and unmanned diamond mining equipment differ according to the different tasks each piece of equipment must carry out.


   



    3.1. Intelligent rock-drilling jumbo


    Rock drilling is the key process in mining, and plays a very important role in productivity, cost, and efficiency. Different geological conditions require different mining methods, and different methods require different types of rock drilling. A hydraulic rock-drilling jumbo is needed for medium-length hole drilling (i.e., depth of 20–30?m, diameter of 60–100?mm) [12]. An intelligent and unmanned rock-drilling jumbo has been designed to support intelligent mining technology and efficiently complete drilling work.


   



    Remote control and a virtual-reality display were the first basic technologies implemented in the unmanned hydraulic rock-drilling jumbo. Fig. 4 shows the initial unmanned control platform for the jumbo on the surface. The virtual prototype display system, including on-site audio and video signals, is well-integrated in order to increase the feeling of immersion while performing remote-control operations.


   



    Furthermore, the rock-drilling jumbo is autonomously controlled and operated in the tunnel under the guidance of a positioning and navigation system. By coordinating the positioning system and altitude control system, the jumbo can achieve autonomous driving to the location from the dispatch layer. This is a major step toward achieving continuous operation without interference. Given the coordinates of the drilling-hole position in the three-dimensional (3D) digital map of the mine, the identification of the stope top and floor and the accurate positioning of the rock-drilling system can be achieved independently. This provides a basis for unmanned operation. The intelligent control flow diagram is shown in Fig. 5.


   



    The rock-drilling parameters are independently adjusted according to the rock conditions. The intelligent rock-drilling jumbo (shown in Fig. 6) is equipped with components for intelligent blockage prevention, rock-characteristic acquisition, and frequency matching; an automatic rod function; and a fully automatic drill-pipe bank. The hole-blasting parameters are specified independently, according to the scheduling system that is used, in order to ensure continuous drilling.