Intelligent open-pit mine construction basic framework and system design

0 Introduction

Mineral resources are an indispensable material basis for human survival, economic construction and social development. Coal has long been the main energy source in China, accounting for more than 60% of primary energy production and consumption. It is expected that coal will remain the main energy source in China before 2050. Coal industry is an important basic industry related to national economic lifeline and energy security, the development of technology and intelligent project management is the only way for its sustainable development. At present, intelligence, as a subversive innovative technology, has become the core driving force for the transformation of basic industrial industries worldwide, and is exerting a profound impact on the development strategies and national economies of various countries in a larger scope and at a deeper level. It has become the core key to reshaping the development form of traditional industries worldwide, enhancing the international core competitiveness of industries and improving the total factor productivity. It has epoch-making significance. The adoption of intelligent high-tech to drive the transformation and upgrading of traditional mining industry can essentially enhance the core competitiveness of mining enterprises, thus promoting the development of traditional mining industry towards the goals of safety, efficiency, economy, green and sustainable development [1-2], and standing out in the increasingly fierce international market competition.

In recent years, the rise of disruptive technologies such as Internet +, artificial intelligence and big data has opened the prelude to the fourth industrial revolution and accelerated the process of change in traditional industries. Germany proposed Industry 4.0, the United States proposed the "Smart Planet", and China proposed the "Made in China 2025" strategy. The development of intelligent manufacturing, intelligent equipment and intelligent production has become the mainstream direction of industrial development. Therefore, taking advantage of the opportunity of this industrial revolution, the construction of smart coal mine and the development of intelligent mining are in line with the national strategy, and are also the inevitable choice to solve the current problems and development of the coal industry. Compared with the open-pit mining, it is more suitable to build a modern mine that meets the requirements of wisdom [3-5].

Foreign countries began to study intelligent mining technology in open pit mining in the 1990s, and developed countries such as the United States, Canada, Australia, and Germany have put forward their own technical solutions. In view of intelligent development and design, Western mining powers have successively launched mining commercial software for geological data processing, mineral deposit modeling, mining design, planning, mapping graphics processing and other aspects. British Mining Computing Limited (MICL) developed Datamine mining software system, including geological information processing, deposit model construction, mining design, mine scheduling and planning modules, which are mainly used in geological exploration data processing, open pit or underground mining design, mine scheduling and production planning. Surpac Software International (SSI) developed Surpac Software, a 3D interactive graphics software system for surface survey data processing, geological exploration data analysis, and mining design. Its application areas include exploration and geological modeling, resource assessment, surface and underground mining design, production planning and mining schedule planning, and tailings and reclamation design. The Vulcan software developed by MAPTEK in Australia integrates geological deposit modeling [8], mining design and schedule planning. Geostatistics can be used to process raw data and predict grade changes, and open pit or underground mining design and production schedule can be arranged [6-10].

In terms of equipment and process intelligence, Bucyrus control system uses modern computer technology to update the original automation, and introduces a programmable control system for drilling. It is a PLC video system composed of programmable logic controller and display, which can provide various performance parameters of the operation to the driver at any time during the drilling process. Through the Rig Monitoring System (IRDMS), the driver monitors the drilling parameters (drilling speed, hole depth, total footage and number of holes drilled) from the console in the driver's cab. Faults related to mechanical and system function, temperature, pressure and filter condition of key components can also be diagnosed. The data can be transmitted to a computer outside the rig, or connected to the mine wireless system. The CAT transport equipment automation system includes positioning, environmental (road condition) detection, machine control, wireless communication and position control, the GNSS receiver continuously monitors the truck's position and direction, the laser rangefinder scans the road in front of the truck to determine if there are obstacles, and the data is processed by computer to tell the operating robot how to avoid them. In 2013, in cooperation with Caterpillar, Forteske Metal Group signed a driverless truck agreement in the Solomon iron mining area, and the first batch of 8 autonomous 793F mining trucks were put into use in the mining area, so far there have been 54 autonomous trucks, and the cumulative volume of driverless trucks has reached 240 million tons [11-24].

Compared with foreign developed countries, China's intelligent mining technology started late, but with the rapid development of science and technology in our country, especially the rapid development of mining software and the promotion of enterprise digital management concept, so that domestic mines have the conditions for the construction of digital mines. At present, some mines in China have realized the digital control of single or several joint business modules such as mine perforation, blasting, model updating and ore blending. The representative intelligent mining design in China includes DIMINE software developed by Central South University, 3Dmine developed by Sandiman Company, LongRuanGIS developed by Peking University and Longsoft Technology, and mining area Resource and Environment Information System (MREIS) developed by the General Institute of Coal Science and Technology. DIMINE software provides a complete set of digital mining solutions, which can be used in geological exploration data analysis, geological body 3D modeling, resource evaluation and reserve calculation, open pit and underground mining optimization design, ventilation network solution, mining planning, local and overall mine rapid modeling and other work. 3DMine software developed by Sandiman Company is mainly used in solid mineral geological exploration data management, mineral deposit geological model, traditional and modern geological reserves calculation, open-pit and underground mine mining design, open-pit short-term schedule and production facility data, planning target data of practical 3D visualization foundation platform construction. The software includes 3D software interface design and modular software structure, and realizes the information sharing of geology, survey, mining and production management. It has good data compatibility with domestic and foreign graphics software, and is a relatively leading 3D mining software in China.

Domestic open-pit mine in the design planning research, education technology, mine development and other aspects of information, automation, etc., has also been a certain development. The informatization and intelligent construction of large-scale mines such as Huaneng Yimin open-pit Mine, Shenhua Zheneng Group and China Coal Pingshuo Group have improved the penetration rate of digital design tools, the numerical control rate of key process flow and the automation degree of mine production and operation management [25-34].

Huaneng Yimin Coal Power Company's open pit mine attaches great importance to the use of information technology to transform and improve traditional industries, and has done a lot of work in enterprise informatization, digitization and automation. Since 1997, it has successively established truck automatic dispatching system, management information system (MIS), drainage centralized control system, crushing belt centralized control system, etc. A high-speed enterprise network based on optical fiber has been built. The use of these systems provides advanced technical means for the production, operation and management of open-pit mines, and obtains good economic and social benefits.

National Energy Investment Group in accordance with the national energy Investment Group informatization master plan and digital mine guidance planning as the basis, combined with the digital mine construction status of the group and the need to reduce costs and increase efficiency, under the guidance of advanced technology, design concepts and management ideas, the construction of the general application architecture of the digital mine. Monitoring and monitoring systems have been built including ground production system centralized control system, truck dispatching system, vehicle collision warning system, slope stability monitoring system, truck tire online monitoring system, fuel monitoring system, power supply and distribution monitoring system, industrial television system, wireless communication system, etc. Production management systems have been built, including comprehensive monitoring and scheduling command, production execution system, team management system, PM equipment management system, cost analysis and display system, maintenance operation safety control system, coal quality analysis system; In terms of production technology, the system has been built, including the design system of throwdown blasting, the integrated pre-control system of stripping and drainage and land reclamation, to realize three-dimensional simulation display; Management has built ERP, OA, etc.

China Coal Pingshuo Group Company has realized the informationization of production and operation management through the information construction, and the intelligent monitoring and scheduling system of truck operation and drilling rig operation has improved the safety control ability and the efficiency of the production process system. Production system information system has been built including open pit GPS intelligent truck scheduling system, drilling rig high-precision automatic layout navigation and depth detection system, emulsion explosive truck dynamic monitoring system, anti-collision system, overspeed alarm system; Coal mine management information system has been built including the company automation office OA system, the company ERP system and asset life management system (EAM).

The intelligent surface mine is mainly reflected in the following aspects:

1) Large-scale application of open-pit mine automation equipment and automation system. For example, the dynamic perception of the operating environment of open-pit mines, the automatic operation and intelligent maintenance and inspection of perforation, mining and transportation equipment, and the big data collection and analysis of the whole process system.

2) Integrated control of production design and mine engineering construction. For example, the application of automated aided design software ensures the optimization of production design, and the automatic generation of construction plans, instruction push and intelligent operation guidance system strictly ensures the accurate implementation of design.

3) Integration, data processing and decision-making of information data link. For example, big data analysis of production factors such as people, property and other technologies in the production process of mines ensures efficient and rapid information management of mine production [35-37].

Through the application of the above automation, intelligence, information and other technologies, foreign open-pit mines are gradually developing towards a safe, efficient, green and intelligent mine. According to the data released by the U.S. Energy Information Administration (U.S. Energy Information Administration), the number of open pit coal mine employees in the United States in 2010 was 28,709, and the average simplex mining efficiency (total labor productivity) was 9.46 t/h; In 2017, the number of employees in open pit coal mines in the United States decreased by 25.08% compared with 2010, reaching 21,509, while the average simplex mining efficiency increased to 10.92 t/h, an increase of 15.43%, and the results of "reducing people and increasing efficiency" were significant.

In the past 1 to 2 years, the foreign open-pit coal industry has entered a key stage of cross-era development, it is reported that in August 2018, Australia's Rio Tinto announced the launch of the world's first "pure intelligent mine" project in Western Australia Koodaideri mine, mine transformation is expected to be completed in 2021. By then, the Koodaideri mine's production system will consist of a network of intelligent equipment filled with robots, driverless mining cars, driverless trucks, driverless RIGS and driverless freight trains, becoming a true unmanned intelligent open-pit mine.

At present, the development of informatization and automation in China's coal mines is gradually improving, and the intelligent construction of coal mines is in its initial stage. For many key problems encountered in the intelligent construction of coal mines, domestic and foreign scholars have carried out a large number of in-depth studies. As early as the end of the last century, Li Zhongxue put forward a mining concept oriented to knowledge economy and sustainable development, requiring the mining industry to comprehensively strengthen technological innovation and adopt new technologies such as intelligence to accelerate the development from labor-intensive industries to technology-intensive industries.  Wang Guofa and Chen Xiaojing, based on the current development status of digital mining technology, combined with the intelligent characteristics and requirements of the production system, gave the concept and connotation of smart mining: the integration of the Internet of things, cloud computing, big data, artificial intelligence, automatic control, mobile Internet, robotized equipment and modern mining development technology to form mine perception, interconnection, analysis, self-learning, prediction and determination A complete intelligent system for policy and control; By 2025, the intelligent development of single system in coal mine will be realized in the direction of multi-system intelligence, the basic operating framework of intelligent production, intelligent security and intelligent security system will be established, and the second stage goal of intelligent coal mine with spatial digitization, information integration, equipment interconnection, virtual-real integration and control network will be initially formed. Realize the intelligent operation of the whole process of mine development, mining, transportation, washing, safety guarantee, ecological protection, production management, etc. The level of resource exploitation and utilization has been significantly improved, occupational health and working environment in coal mines have been fundamentally improved, and ecological restoration and protection of mines have been fully implemented [38-41].  However, the previous research only from the definition of intelligent open-pit mine, key technology research, overall framework research, a single system unit to do more in-depth research, did not carry out the overall planning of intelligent open-pit mine from a global perspective, especially never for the intelligent construction of China's open-pit coal mine research and architecture design.

Compared with the intelligent construction of mining and mining, the intelligent construction of open-pit mining is easier to realize and form a complete intelligent ecological network. Open-pit mine is a complex large-scale system, the most prominent feature is the multiple levels of business and complex structure of business system. Intelligent upgrading is the process of comprehensive upgrading and transformation of all components of the large system, and the goal of upgrading is not only reflected in a single equipment and a single link, but also mainly reflected in the common sharing and efficient use of information across equipment, across process links, across process systems, and across business categories. Therefore, in order to ensure the scientific, systematic and orderly construction of intelligent open-pit mine, it is necessary to make detailed planning and research on the theory, technology and overall construction plan of intelligent open-pit mine in a comprehensive and systematic way [46-48].

1 Definition of intelligent open pit mine

From the perspective of production factors of open-pit mines, the essence of intelligent open-pit mines is to deeply integrate the information technology across the two industrial revolutions with the open-pit coal industry, and through the information technology of production, safety, management, design and other work and the intelligence of mining machinery, so as to achieve a substantial increase in labor productivity of open-pit mines and a substantial reduction in the overall production cost.

From the perspective of system theory, cybernetics and information theory, intelligent open-pit mining is a complex system with mutual mapping, timely interaction and efficient collaboration between human, machine, material, environment and information in the process of open-pit mining by integrating advanced information technology such as perception, calculation, communication and control and automatic control technology. Realize on-demand response, fast iteration and dynamic optimization of resource allocation and operation in the system.

The so-called intelligent open-pit mine is based on digitization of mine data, production automation and management information, combined with new sensor technology, network communication technology, spatial information technology, artificial intelligence technology, etc., to realize intelligent perception, identification, memory, analysis and calculation, judgment and decision making, evaluation and assessment improvement of mine production and management, and achieve unmanned or less unmanned of the entire mine. Achieve green, safe and efficient mine [49-56].

2 Principles of intelligent open-pit mine construction

2.1 In accordance with the construction principle of "intelligent unit - intelligent system - intelligent large system"

(1) Division of system structure level

(1) Division of system structure level

Open-pit mine is a complex large-scale system, the most prominent feature is the multiple levels of business and complex structure of business system. The intelligent open-pit mine is necessarily the process of comprehensive upgrading and transformation of all components of the open-pit mine system, and the goal of upgrading is not only reflected in a single equipment and a single link, but also mainly reflected in the common sharing and efficient use of information across equipment, across process links, across process systems and across business categories. Therefore, in order to ensure the scientific, systematic and orderly development of intelligent open-pit mine construction, it is necessary to divide the entire intelligent mine system into three levels, namely intelligent unit, intelligent system and intelligent large system, according to the hierarchical level of the system, as follows:

1) Intelligence unit level

The intelligent unit is the indivisible smallest unit of the intelligent open-pit mine. Its essence is to perceive the state of the physical entity and the environment through software, calculate and analyze it, and finally control it to the physical entity, build the most basic closed loop of automatic data flow, and form the integration and interaction between the physical world and the information world [57]. At the same time, in order to interact with the outside world, the smart unit should have communication functions. The intelligent unit is the smallest intelligent open-pit mine unit with the functions of perception, computation, interaction, extensibility and self-decision. For example, the hardware and software of a truck to achieve positioning function constitute the smallest intelligence unit.

2) Intelligent system level

On the basis of the intelligent unit, through the introduction of the network, multiple intelligent units can communicate with each other and cooperate to form an intelligent system, such as the truck scheduling system (as shown in Figure 1). The intelligent system can realize a wider range and wider field of data flow, realize the interconnection, interoperability and interoperability of multiple intelligent units, and further improve the breadth, depth and accuracy of the optimal allocation of production resources. Based on the state perception, information interaction and real-time analysis of multiple intelligent units, the intelligent system realizes the self-organization, self-configuration, self-decision-making and self-optimization of local production resources [58]. On the basis of the smart unit function, the smart system also mainly includes interconnection, plug and play, edge gateway, data interoperability, collaborative control, monitoring and diagnosis.

3) Intelligent large system level

On the basis of the intelligent system, through the construction of intelligent service platform, to achieve the efficient cooperation between many systems covering production, management, operation and sales, constitute the intelligent open-pit mountain system (as shown in Figure 2). Such as covering perforation, blasting, mining, transportation, disposal, reclamation, maintenance, finance, management, security, sales, design and other large-scale service platforms.

The intelligent large system mainly realizes the convergence of data, so as to optimize assets internally and form operational optimization services externally. Its main functions include: data storage, data fusion, distributed computing, big data analysis, data services, and on the basis of data services formed asset performance management and operation optimization services. Intelligent large systems can realize cross-system and cross-platform interconnection, interoperability and interoperability through big data platforms, and realize comprehensive information perception, in-depth analysis, scientific decision-making and accurate execution in the global scope [59]. These data are partially stored in the intelligent open pit mine intelligent service platform, and partially dispersed in each component. Unified management and integration of these data, as well as distributed computing and big data analysis capabilities of these data, enable these data to provide data services and effectively support the basis of advanced applications [60].

2.2 Digitalization - automation - intelligent construction principle

In recent years, the rapid development of intelligent technology has continuously integrated in traditional industries, resulting in a number of new intelligent devices, perceptual forms and networking methods, which have played a significant role in promoting the development and transformation of basic industries. The application cases of the development and upgrading process of "intelligent design, intelligent production, intelligent service, intelligent application" and other industrial fields are summarized (as shown in Figure 3). The following conclusions can be concluded: Intelligent technology has significantly improved system production efficiency in various application scenarios by building a closed-loop system of "state perception, real-time analysis, scientific decision-making, and accurate execution" [61].

For example, in the production and operation of the basic industry of energy mining, it is generally composed of the four elements of "human, machine, environment and pipe", but the personnel in the traditional production model is uncontrollable, the environment is difficult to predict, and the management is difficult, so the operation, monitoring and management of production equipment are extremely inconvenient. In addition, due to the inability of communication between equipment and equipment, the production process lacks coordination, resulting in the phenomenon of idle equipment or insufficient equipment, resulting in unreasonable and wasteful allocation of production resources and production capacity.

Through the "digitization" of uncertainty factors, the "automation" or even "intelligence" of the production process can be realized, so as to build a closed-loop system of "state perception, real-time analysis, scientific decision-making and accurate execution" in the mining process, which can solve the complexity and uncertainty problems in the design, production, management and operation processes, and improve the efficiency of resource allocation. Realize resource optimization.

Considering that the current understanding and grasp of the accurate meaning of "digital-automation-intelligent" and their mutual relations are not unified, it is necessary to combine the characteristics of open pit mines, and accurately describe the definitions and concepts in the construction of intelligent open pit mines, as follows:

1) Digitalization. Digitization is the basis for the development of computer, multimedia technology, software technology and intelligent technology, and is also one of the basic components of information technology system. "Digitization" focuses on data collection and quantification, and mainly realizes the perception of physical state. Open-pit digitization generally marks the early stage of the application of computer technology in mine development, research and production management, which focuses on the collection, storage and processing of mine information to achieve digitization, which is the basis of intelligent open-pit mine construction [62].

2) Automation. Automation refers to the process of machine equipment, system or process (production, management process) without the direct participation of people or less people, according to the requirements of people, through automatic detection, information processing, analysis and judgment, manipulation and control, to achieve the expected goal.

The concept of automation is a dynamic development process. In the past, people's understanding of automation, or the functional goal of automation, was to replace human operations with mechanical actions to automatically complete certain tasks. This is essentially the idea of automation replacing human manual labor. Later, with the development of electronic and information technology, especially with the emergence and widespread application of computers, the concept of automation has been expanded to use machines (including computers) not only to replace human physical labor but also to replace or assist mental labor to automatically complete specific tasks [63].

3) Intelligence. Compared with automation, intelligence has the following characteristics: first, it has the perception ability, that is, it has the ability to perceive the external world and obtain external information; Second, they have the ability of memory and thinking, and can use the existing knowledge to analyze, calculate, compare, judge, associate and make decisions. The third is the ability to learn and adaptive ability, that is, through the interaction with the environment, continuous learning and accumulation of knowledge, so that they can adapt to environmental changes; The fourth is the ability to make behavioral decisions, that is, to respond to external stimuli, form decisions and convey corresponding information. Therefore, intelligence is a high-level automation, different from the concept of "general automation", intelligence covers the two functions of perception and cognition, and emphasizes the ability of "memory, thinking, learning and self-adaptation" [64].

To sum up, in the development process of intelligent open-pit mines, the development steps of "digitalization - automation - intelligence" should be followed. On the basis of the gradual implementation of digitalization and automation, a closed-loop system of state perception, real-time analysis, scientific decision-making and accurate execution should be built in the mining process to solve the complexity and uncertainty problems in the design, production, management and operation processes. Improve the efficiency of resource allocation and realize resource optimization [65].