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A series of laboratory scale studies has been conducted to assess the thermal response of common rock types in Fennoscandinavia. ... Impact of fire on the stability of hard rock tunnels in Sweden. E. Nordlund Ping Zhang S. Dineva D. Saiang Ganesh Mainali. ... A Study On A New Concept Of Thermal Hard Rock Crushing. K. Thirumalai J. B. Cheung ...
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properties of hard rocks aected by microwave radiation is imperative for improving hard rock crushing eciency. Rock is a temperature-sensitive material due to the ther-mal …
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A new concept of thermal crushing of hard rocks is examined in this study. The theoretical methods developed to analyze thermal stresses and fragmentation induced …
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Thermal drilling of rock, e. g. Laser (supported) Jet drilling (LJD), could potentially become such a next fundamental change and thus, greatly improve drilling of hard rock. The International ...
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To explore the basic mechanism of non-penetrating crushing case during HVPF, some coring samples are taken with this crushing appearances. The thermal effect and chemical effect of basalt occupies a considerable proportion in the experiment, and it's difficult to reflect its electrical effect. The existence of the propagation cracks will make ...
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Comprehensive can be obtained, with 2.3 chapters crushing zone radius as the reference, blasthole and hollow hole distance in less than 2.5 times the radius of the crushing zone, the main force ...
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Ultrasonic vibration rock crushing technology is a new type of rock crushing method, and it can be used in hard rock drilling. By applying high-frequency cyclic load to the rock, it promotes the expansion and penetration of micro-cracks inside the rock, causing fatigue damage, reducing the rock strength, and thus improving the rock …
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Thermal rock breakage: Plasma method: Under the high-temperature and high-speed plasma arc, the thermal stress generated exceeds the strength limit of the rock, thereby crushing the rock: …
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Atmospheric Pollution Research. Dust emission from crushing of hard rock aggregates. During secondary crushing, the background concentrations were achieved at a 350 m distance for coarse particles. Dust concentrations in the limestone quarry were half of that measured in quarries processing granitic rock material.
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Zhao 11 studied the thermal damage of granite during the ultrasonic vibration excitation process and reported that pores expanded significantly when the rock temperature exceeded a certain threshold. ... In projects with large rock fragments, such as the break-up and excavation of tunnels in hard rock masses, crushing of large …
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Meanwhile, they also established the elastic-plastic damage constitutive model of hard rock and stress-energy-rigid-damage multi-criteria rock failure model and revealed the mode of stress release and dissipation in the process of rock failure from the perspective of energy. ... Infrared thermal images of sandstone crushing at different …
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Bruno Grafe. Download Free PDF. View PDF. Session: D53/ Modeling and Simulations, Part II Rock Crushing using Microwave Pre-treatment Seunghee Kim1, A.M. ASCE and J. Carlos Santamarina2, M. ASCE 1 Assistant Professor, Western New England University, 1215 Wilbraham Rd, Springfield, MA 01119-2684, USA 2 Professor, King Abdullah …
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1.1 Principle. Crushing is used to very quickly produce a fine powder from a bulk material or fine particle using mechanical crushing. This technique is essentially used to investigate ceramics, minerals, and mixed–composite materials. Materials must be brittle or made brittle and of a high hardness to average hardness.
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The thermal spallation of rocks was proposed in 1930s (Preston and White 1934 ), and its main principle is that localized heating induces uneven expansion stress …
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Sensitive blasting technology, commonly known as non-explosive (nonex) rock-breaking methods, are starting to gain attention in hardrock ore mining (Pickering and Young, 2017; Zhou et al., 2018). ...
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Since most of the current researches on the crushed-rock interlayer for highway embankment in permafrost region are based on thermal properties, there are few studies on their mechanical deformation characteristics. In order to study the deformation and failure process of crushed-rock interlayer under the long-term settlement …
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The U.S. Department of Energy's Office of Scientific and Technical Information
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Abstract. The fundamental principles of rock fragmentation by crushing, blasting, and drilling are not well understood; however, empirical observations have provided means for predicting the energy requirements for these processes. Experimental procedures and methods of analysis used in comminution studies are described in this review.
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But with this thermal camera, which is basically a sensor for infrared radiation (heat), we get a whole new way to enjoy smoosh smoosh pancake time. As far as why the metal heats up as it's ...
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A new concept of thermal rock crushing is examined in this study by the Bureau of Mines in cooperation with the U.S. Army Advanced Materiel Concepts Agency …
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IMPACTORS FOR SECONDARY AND HARD ROCK CRUSHING . HAZEMAG Impactors for Secondary Crushing applications embody a combination of modern equipment design, highly developed hydraulics, and the latest control systems. ... problems by the provision of indirect heating of feed plates and impact aprons through installation of a circulating …
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Hard rock crushing 1. Granite Granite, which is formed by igneous rock, is a lenticular hard rock with a carbon dioxide content of more than 70%. It is mainly composed of quartz, feldspar, a small amount of biotite and other dark minerals. Granite is a strong and dense building material with high compressive strength, low water absorption …
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Weakening rocks using microwave irradiation has been a major topic in research for the past 50 years. However, the thermal effect of microwaves on rocks is mostly studied with a multi-mode metal cavity, in which rocks absorb microwaves reflected from all directions, and this method cannot represent how the microwave pre-treatment …
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(ii) When detonating outside the weak interlayer, if the interlayer is within about 4 times radius of the crushing area, the hard rock on both sides of the weak interlayer will in a high stress state.
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Understanding the tensile behaviors of the typical hard rock under microwave irradiation is indispensable for the microwave-assisted hard rock breakage technology. In this study, we quantitatively investigated the thermal damage of granite subjected to microwave irradiation by ultra-sound tests and NMR tests. In order to study the variation
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The high-energy beam laser breaking of rock is an emerging noncontact physical rock-breaking method. The technology of laser thermal rock breaking has the advantages of energy concentration, high rock breaking efficiency, and no mechanical wear.An experimental study of laser thermal rock breaking was conducted to study the …
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Crushing is a size reduction process that plays a key role in both mineral processing and crushing–screening plant design. Investigations on rock crushability have become an important issue in ...
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The concept of thermal hard rock crushing is new and supporting theoretical or experimental investigations are nonexistent. A theoretical and experimental approach …
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Thermal desorption is a process whereby samples are gradually heated ... if hard rock crushing facilities for construction aggregate in Norway could be adapted for mechanochemical CO 2 capture, ...
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Huang [14], and Song [15] used the coupled Eulerian–Lagrangian simulation to study granite jet crushing under multiple field conditions, and the results showed that the rock damage crushing was caused by a combination of thermal stress, abrasive impact load, and water wedge.
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where, (overline{{k_{n} }}) is the bond's normal stiffness, (A) is the area of the bond cross-section(m 2), (alpha) is the expansion coefficient of the bond material, and (Delta T) is the temperature increment. 2.3 Numerical Simulation Theory. In the thermal calculation module, thermal material is represented as a network of heat reservoirs. …
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A new concept of thermal crushing of hard rocks is examined in this study. The theoretical methods developed to analyze thermal stresses and fragmentation induced …
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Obtain the law of temperature to rock crushing with ultrasonic vibration. Abstract. Ultrasonic vibration technology as a new type of auxiliary lithotripsy …
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A thermal round, analogous to an explosive blasting round, was designed and tested In situ for breaking of hard rock for rapid excavation. In burdens where three pre faces are …
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Ferri Hassani et al. point out that when crushing hard rock with high strength, not only are mechanical rock-breaking methods inefficient and ineffective in terms of breaking rock, ... one category is the use of primarily thermal energy to break rock, like laser and microwave rock breaking, while the other category is still predominantly based ...
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