Zongxian Zhang

Zongxian Zhang
University of Oulu · Oulu Mining School

PhD

About

129
Publications
74,392
Reads
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1,860
Citations
Introduction
Current research interests: mining technology with high recovery ratio and high energy efficiency, mechanism of rock fracture and fragmentation, advanced blasting technology, rock mass evaluation and classification, optimization from mine to mill, muography's applications and digital mining. Research methods: Physical model blasting; lab experiments for static and dynamic rock fracture/fragmentation; stress wave and rock mechanics theories; numerical simulation; field or industry tests.
Additional affiliations
January 2017 - present
University of Oulu
Position
  • Professor (Full)
February 2013 - present
University Centre in Svalbard (UNIS)
Position
  • Professor (2014-); Associate Professr (2013-2014)
February 2013 - present
University Centre in Svalbard (UNIS)
Position
  • Professor (2014-); Associate Professor (2013-2014)
Description
  • Courses taught: Rock Mechanics and Engineering Geology; Advanced Rock Mechanics and Engineering Geology
Education
September 1997 - September 2001
Luleå University of Technology
Field of study
  • Mining Engineering
September 1983 - June 1986
University of Science and Technology Beijing
Field of study
  • Mining Engineering
September 1978 - July 1982
Xi'an University of Architecture and Technology
Field of study
  • Mining Engineering

Publications

Publications (129)
Article
Full-text available
The effect of a blasting vibration from an excavating tunnel on an adjacent excavated tunnel is of great importance for the stability and security of twin tunnels. Due to the relatively small distance between the tunnel face of the excavating tunnel and the concrete lining of the excavated tunnel, the impact of blasting could be significant and sho...
Article
Full-text available
Fragmentation of granite cylinders having a centric charge with different decoupling ratios was investigated in blast experiments. Conclusions are made from studying the post-blast specimens and strain measurement. Eight blasting tests were carried out on granite cylinders having a diameter of 240 mm and a length of 300 mm. All the specimens had a...
Article
Full-text available
Rock properties are important for design of surface and underground mines as well as civil engineering projects. Among important rock properties is the characteristic impedance of rock. Characteristic impedance plays a crucial role in solving problems of shock waves in mining engineering. The characteristics impedance of rock has been related with...
Article
Full-text available
Blast-induced rock movement (BIRM) may lead to large ore loss and dilution in many mines using the pre-blast ore boundary to guide shovel loading. In this study, a simulation approach consisting of the finite element method for blast loading calculation and the bonded-particle method for bench blasting simulation was applied to study the BIRM. Firs...
Article
Full-text available
Based on the review of a wide range of literature, this paper fnds that: (1) the average specifc surface energy of various single crystals is only 0.8 J/m2 . (2) The average specifc fracture energy of the rocks with a pre-crack under static cleavage tests is 4.6 J/m2 . (3) The average specifc fracture energy of the rocks with a pre-cut notch but...
Chapter
Cosmic‐ray muography has several current and many promising future applications in geosciences, geotechnical engineering, and mining engineering. Muography, if applied to these disciplines, is based on alternating muon flux attenuation in soils and rocks due to anomalous density heterogeneity in the media. Muography can be used for detecting and im...
Presentation
Full-text available
This presentation covers most applications of rock dynamics in mining engineering.
Article
Full-text available
The effect of detonator position on rock fragmentation was studied at the Kevitsa open pit mine. Five full-scale field tests were conducted where the blasts were divided into test and reference areas, and compared with each other. In the test areas, the detonators were placed at or near the middle point of the explosive column, and in the reference...
Article
Full-text available
Empirical relationships for estimating Uniaxial Compressive Strength (UCS) of rock from other rock properties are numerous in literature. This is because the laboratory procedure for determination of UCS from compression tests is cumbersome, time consuming, and often considered expensive, especially for small to medium-sized mining engineering proj...
Article
Full-text available
Small-scale model blasting plays an important role in understanding mechanism of rock fragmentation by blasting and improving blast technology in rock and mining engineering. Because a specimen (or model) often needs to be placed on either a ground or another material in model blasting, an additional interface appears between the specimen and the g...
Article
With continuously increasing urban construction, more underground projects require the breaking of rocks near sensitive areas, such as hospitals, schools, and residential areas. On one hand, since conventional blasting that uses explosives has a negative impact on the safety of the surrounding buildings and brings about noise and flying rocks, the...
Article
Full-text available
Based on the data of global mineral production and ore recovery in mining and mineral processing, this paper presents the annual production of 25 minerals and calculates the annual losses of 20 minerals from the year 1920 to 2018. The results indicate that the annual production of 23 minerals has increased by between 1 and 930 times since 1920, sim...
Article
Full-text available
Nine blasts with cylindrical granite specimens were carried out under different stemming conditions. All rock specimens had a diameter of 240 mm and a length of 300 mm. Explosive Pentaerythritol tetranitrate (PETN) with specific charges 0.2 and 0.3 kg/m 3 were used, and the blasts were carried out in a large explosion chamber. Each rock specimen wa...
Article
Full-text available
An analytical relation between burden velocityand ratio of burden to blasthole diameter is developed in this paper. This relation is found to be consistent with the measured burden velocities of all 37 full-scale blasts found from published articles. These blasts include single-hole blasts, multi-hole blasts, and simultaneously-initiated blasts wit...
Conference Paper
Full-text available
The novel geophysical remote imaging method of muography is based on cosmic-ray induced muon particles that are detected after passing through the media of interest. If the studied objects are solid, their sizes can vary from meters to up to kilometres. In underground tunnelling, muography has at least four applications: (1) muography can be used t...
Article
Full-text available
Published in MATERIA 2021;2-3:63-66 The idea of mine-to-mill optimization has been tested in various mines in last decades, resulting in higher mill throughput in many mines, but also unsatisfactory results in others. These contrary results have largely confused engineers and leaders in mining industry and have made them to lose the confidence in m...
Article
Full-text available
Crack velocity, gas ejection, and stress waves play an important role in determining delay time, designing a blast and understanding the mechanism of rock fragmentation by blasting. In this paper, the emerging times of the earliest cracks and gas ejection on the lateral surfaces of cylindrical granite specimens with a diameter of 240 mm and a lengt...
Article
Full-text available
To investigate energy dissipation and particle size distribution of rock under dynamic loads, a series of dynamic compression tests of granite specimens were conducted using a conventional split-Hopkinson pressure bar (SHPB) device with a high-speed camera. The experimental results show that the dissipated energy increases linearly with an increasi...
Article
Full-text available
Muography is a novel imaging method using natural cosmic-ray radiation for characterising and monitoring variation in average material density in a diverse range of objects that cannot be imaged by conventional imaging techniques. Muography includes muon radiography and muon tomography. Cosmic-ray-induced muons were discovered in the 1930’s, but ra...
Article
Full-text available
Based on a great number of experimental data on various mechanical properties of rock in the literature, six empirical equations between the characteristic impedance (product of density and P-wave velocity) and mechanical properties of rock are proposed. These properties include uniaxial compressive strength, tensile strength, shear strength, mode...
Conference Paper
Full-text available
In order to control the scale of blasting in the excavation of a tunnel and mitigate the blast-caused adverse effects, especially on its neighboring tunnel, the particle velocities of the concrete lining of an excavated tunnel caused by the blasts in its adjacent operating tunnel, were analyzed in ANSYS/LS-DYNA software. The simulated results are c...
Conference Paper
Full-text available
Spherical weathering body is one of complex geological strata, and drill and blast method can be used to precondition the boulders. To mitigate the adverse effects caused by boulder blasting, the particle velocities in the water-intake tunnel segments of Taishan nuclear power plant were measured. The measurement results indicated: (1) The particle...
Article
In rock blasting, there are different constraint conditions such as a free surface, a partial free surface and a free surface with a barrier nearby. These conditions were modelled by three groups of blasting tests in this study: (1) A cylindrical granite specimen was blasted with complete free surfaces to model the free surface condition. (2) A cyl...
Article
Ten blasts with cylindrical granite specimens were carried out in four groups with different specific charges and different constraint conditions. All rock specimens came from a granite quarry and they were cylinders with a diameter of 240 mm and a length of 300 mm. Three specific charges-0.2, 0.3 and 0.6 kg/m 3 with Research Department Explosive (...
Article
Full-text available
Professor of Mining Engineering, Oulu Mining School, University of Oulu Explosives are the materials that can rapidly decompose chemically, produce an extremely high pressure, and release a huge amount of energy at a moment. For example, upon detonation, an explosive can produce a pressure over 20 GPa and a temperature above 3000°C (Zhang 2016a). E...
Conference Paper
Full-text available
Muography is a technique that produces density images of solid objects (or liquids within solids) by utilising detection of highly penetrative muon particles as they travel at relativistic speeds through the muon detector positioned behind the target of interest. Muography can be used as an independent method to determine the relative densities of...
Article
Full-text available
In an extremely competitive mining industry, onsite experience is a big advantage. Mining education at the universities is mostly focused on theoretical studies without a possibility of practical training in mining sites. Hence, experimental mines suitable for practical education are needed to provide a platform for systematic research and educatio...
Article
Full-text available
Fractures in rock cylinders with a central blasthole have been investigated, focusing on the borehole expansion, the crushed zone around the borehole, and the effects of the boundary conditions. Nine small-scale blasting tests were carried out on granite cylinders with diameters of either 228 or 240 mm and lengths of 300 mm, with fully coupled or d...
Conference Paper
Full-text available
S: In order to control the scale of blasting in the excavation of a tunnel and mitigate the blast-caused adverse effects, especially on its neighboring tunnel, the particle velocities of the concrete lining of an excavated tunnel caused by the blasts in its adjacent operating tunnel, were analyzed in ANSYS/LS-DYNA software. The simulated results ar...
Article
Full-text available
The fracturing of six granite cubes (400 × 400 × 400 mm³) in response to blast loading was investigated using a combination of data collected from strain gauges and generated by digital image correlation (DIC) of pictures captured using a high-speed camera. This instrumentation permits the observation of the crack initiation, crack opening velocity...
Conference Paper
Full-text available
In an extremely competitive mining industry, onsite experience is a big advantage. Mining education at the universities is mostly focused on theoretical studies without a possibility of practical training in mining sites. Hence, experimental mines suitable for practical education are needed to provide a platform for systematic research and educatio...
Article
The objective of this study was to investigate granite responses to blasting. The focus was on the pressure and attenuation of shock waves in granite. Tests are reported on ten cylinders subjected to explosions from central pressed trinitrotoluene (TNT) charges with approximate density of 1.6 g/cm³. Three cylinders had dimensions Ø150 mm × 200 mm;...
Conference Paper
The fracture process of rock blocks was investigated in an explosion chamber by using a high-speed camera. Four cubic granite specimens with a size of 400 × 400 × 400 mm and a centric vertical borehole were sub-jected to explosion using two charge weights (12g and 6 g). One of lateral surfaces of each specimen was monitored by the camera during the...
Book
Rock Dynamics – Experiments, Theories and Applications is a collection of scientific and technical papers presented at the Third International Conference on Rock Dynamics and Applications (RocDyn-3, Trondheim, Norway, 26-27 June 2018). The papers in the book reflect the recent developments in experiment and theory as well as engineering application...
Conference Paper
The fracture patterns of granite cylinders (the diameter of 228 mm and the length of 300 mm) with different boundary conditions were investigated using blast experiments, where the post-blast specimens and strain measurement were employed to evaluate the results. The five cylinders had a centric vertical borehole and an explosive charge (PETN) of w...
Conference Paper
Full-text available
There are two missions for rock mechanics to accomplish in mining engineering: (1) to destroy rock efficiently; (2) to make rock structures safe. If these two missions are completed and mining operations are well managed, best mining results should be achieved. To accomplish the two missions, rock mechanics faces following challenges: (1) how to ma...
Article
Full-text available
Reduction of energy consumption in comminution is of significant importance in mining industry. To reduce such energy consumption the energy efficiency in an individual operation such as blasting must be increased. By using both new investigations and previous experimental results, this paper demonstrates that (1) kinetic energy carried by moving f...
Chapter
There are two types of detonation: ideal detonation and nonideal detonation. This chapter focuses on ideal, that is, one dimensional, detonation theories, including the Chapman-Jouguet (CJ) theory and the Zeldovich-Neumann-Döring (ZND) theory. Two nonideal theories, the detonation shock dynamics (DSD) theory and the streamline approach, are briefly...
Chapter
Stress waves can be found in rock drilling, rock blasting, mining-induced seismicity, and other dynamic events. By means of stress wave theory, we can improve the quality and productivity of current rock drilling, rock blasting, and mining production; reduce natural resource loss; improve fieldwork safety; and reduce the damage to the environment c...
Chapter
In rock blasting, burden and spacing are two major parameters influencing fragmentation, ground vibrations, and overall costs. The following issues are discussed: angle of breakage; specific charge; stress and energy distribution; decoupling ratio; diameter of blasthole; and factors influencing burden and spacing. The effects of burden and spacing...
Chapter
This chapter includes the following topics: composition of rock; characteristics of rock fracture; definitions of rock strengths; effects of geological structures on rock fracture; Griffith theory such as theoretical strength and Griffith strength relation; relation between rock strengths; relation between rock strength and fracture toughness; proc...
Chapter
Temperature is one of main factors influencing the mechanical behavior of rock. In rock engineering, high temperature is a consideration with rock drilling, rock boring, rock blasting, extraction of geothermal energy and petroleum, and underground repositories of nuclear wastes. This chapter discusses temperature effects on the physical properties,...
Chapter
This chapter describes the process of rock blasting in a single hole on the basis of previous experimental results. This process consists of explosive detonation, borehole expansion, rock crushing close to the borehole, rock fracture outside the borehole, crack propagation, movement of burden, and energy distribution during blasting. The following...
Chapter
In ordinary rock blasting, a free surface and an empty space at a proper distance to the blasthole are two necessary prerequisites for a desirable result such as good fragmentation. This chapter demonstrates the weakness of rock materials and the reasons for spalling. The following topics are dealt with: principles of spalling in rock blasting; eff...
Chapter
This chapter focuses on the blasting in sublevel caving. But the principles in sublevel caving blasting are applicable to other underground mining methods. The following topics are discussed in detail: drilling plan, blast plan, brow damage, misfires, and quantity of rings in each blast. In addition, the following issues are discussed: open cut bla...
Chapter
This chapter introduces the characteristics of shock waves, the Rankine–Hugoniot jump equations, high-speed impact of two different materials, shock wave propagation from a low impedance medium to a high impedance one, shock wave propagation from a high impedance medium to a low impedance one, rarefaction waves, shock wave attenuation, shock wave c...
Chapter
Explosives are the materials that can rapidly decompose, can produce an extremely high pressure, and can release a huge amount of energy at a moment. Explosives are not only powerful but also cheap, compared to many other types of energy. This chapter includes the following issues: introduction to various kinds of explosives; commercial explosives...
Chapter
This chapter focuses on optimum fragmentation which is also called mine-to-mill in mining industry. The topics discussed in the chapter include: effects of blast fragmentation on crushing, grinding, and mineral recovery; factors related to fragmentation; feasibility of optimum fragmentation; measures for achieving optimum fragmentation in practice....
Chapter
Safety First is usually the watchword of an engineering enterprise. In quarries, open pit mines, underground mines, and other kinds of rock engineering, many safety problems are related to rock blasting either directly or indirectly. This chapter mainly discusses various safety problems connected to rock fracture in the mining industry. These probl...
Chapter
This chapter demonstrates that rock blasting greatly influences ore recovery, mining productivity, production cost, rock support, large investments, and so on. The chapter further shows that ore recovery plays an extremely important role in the economy of a mining enterprise. In particular, lower recovery results in not only direct economic loss du...
Chapter
Rock mass in situ involves environmental factors such as water, chemical fluids, confining pressure, cyclic loading, geological structure, and so on, except for loading rate and temperature which have been discussed in chapters: Effect of Loading Rate on Rock Fracture; Effect of Temperature on Rock Fracture. This chapter describes the effects of wa...
Chapter
Open cut blasting plays an important role in tunneling and underground mining. This chapter will discuss the effect of open cut blasting on underground mining and tunneling, introduce two methods for open cut blasting in underground mining, show the procedure of determining the basic parameters of open cut blasting in both underground mining and tu...
Chapter
Various types of rock fracture occur at different loading rates. For example, rock destruction by a boring machine, a jaw or cone crusher, and a grinding roll machine are within the extent of low loading rates, often called quasistatic loading condition. On the contrary, rock fracture in percussive drilling and blasting happens under high loading r...
Chapter
This chapter will describe drilling plan, blast plan, fragmentation, open pit slope, and safety related to open pit mining. The following topics will be discussed: subdrilling, inclination of bench faces, deck charge, air deck, primer placement, stress wave superposition, shock wave collision, rock fragmentation, barrier to free face, fly rocks, an...
Chapter
There is a great scope for developing more techniques not only in rock fracture but also in other applications of explosives since a certain amount of explosive can release a huge amount of energy in just a moment with an extremely high pressure and by a simple operation. This chapter briefly introduces a few blasting techniques. These include demo...
Chapter
This chapter demonstrates that stemming plays a very important role in various kinds of rock blasting. For example, stemming influences detonation energy efficiency, detonation wave distribution, rock fracture, air blast, and fly rock. In addition, the chapter shows that the material properties and sizes of stemming affect rock fracture and fragmen...
Chapter
Rock blasting causes ground vibrations, especially in the nearest inhabitable areas. This chapter describes the characteristics of blast-induced ground vibrations, presents the principles of reducing ground vibrations, and introduces a number of methods for reducing vibrations. The methods like wave superposition, changing initiation sequence (CIS)...
Article
Full-text available
Hanging roofs or high hang-ups, a common problem in sublevel caving mining, usually result in a large ore loss and undermine mining safety. This paper analyzed the formation of a hanging roof and showed that increased confining pressure and reduced free surface were its main characteristics. In order to break down a hanging roof, a new method based...
Book
The purpose of this book is to present a package of comprehensive knowledge in rock fracture and blasting and to demonstrate how to make a scientific design for rock blasting and fragmentation. The book covers the following topics: stress and shock waves; rock fracture characteristics; effects of loading rate, temperature, water and cyclic loads on...
Article
The double-primer placement is based on the principle of shock wave collision. When two shock waves meet each other, the final pressure is greater than the sum of the initial two pressures. Stress analysis indicates that this should be favorable to rock fracture and fragmentation in blasting. This double-primer placement was tested in Malmberget mi...
Article
Full-text available
Borehole instability causes borehole failure, presenting a challenge to the drilling industry. Borehole walls may fail when the surrounding stress exceeds the tensile, the compressive, or the shear strengths of the rock formation, whichever is reached firs. Before filming in the field, a pre-investigation was carried out according to the production...
Article
Full-text available
Instability in production blast holes causes poor fragmentation, lower ore recovery, delay in production and higher costs in crushing and grinding. In this investigation, three large ore bodies named Alliansen, Fabian and Vi-Ri were selected. A video camera was used for mapping production blast holessoastofind borehole stability problems. A total o...
Article
In order to control or reduce the ground vibrations caused by underground blasts in Malmberget mine, a number of blast tests were carried out during production blasts and a series of single shot waveforms were obtained. Then the single shot waveforms from the same ring or different rings were analysed and compared with each other. The results showe...