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By D. Fukahori, K. Sugawara, A. Sato

X-ray Computed Tomography (CT) is a nondestructive imaging technique, and its efficiency is widely recognized. In the present paper, X-ray CT is successfully applied for the visualization of water permeation process in rock. A new experimental technique using a tracer, which mainly consists of Potassium Iodide (KI), is proposed, together with the analysis method of the velocity field. The permeation process and the velocity field in rock are concretely visualized and analyzed by considering the conservation of mass of the tracers. La tomographie calculée aux rayons X est une technique de la prise d'images non-destructive et son efficacité est largement reconnue. Dans le présent exposé, la tomographie calculée aux rayons X Radio est appliquée avec succès à la visualisation du procédé de perméation de l'eau dans la roche. Une nouvelle technique expérimentale, se servant d'un identificateur principalement constitué d'iodure de potassium (KI), est proposée avec la méthode de l'analyse du champ des vitesse. Le procédé de perméation et le champ des vitesse dans la roche sont visualisés concrètement et analysés en considérant la conservation de masse des identificateurs. Röntgen-Computer-Tomografie (CT) ist eine nicht-destruktive Bildverarbeitungstechnik, deren Effizienz weit anerkannt ist. In der vorliegenden Arbeit wird Röntgen-CT erfolgreich für die visuelle Darstellung des Wasser-Durchdringungsvorgangs im Fels eingesetzt. Eine neue experimentelle Technit mit einem Tracer, der hauptsächlich aus Kaliumiodid (KI) besteht, wird vorgeschlagen, zusammen mit der Analysemethode des Geschwindigkeitsfelds. Der Durchdringungsprozess und das Geschwindigkeitsfeld im Fels werden konkret visualisiert und analysiert, wobei die Bewahrung der Masse des Tracers berücksichtigt wird.

Jan 1, 2003

By S. K. Kawatra, R. A. Seitz

The use of inferential particle sizing for closed wet grinding circuit control has been practiced for several years. This paper presents a review of some inferential sizing equations developed for pilot and industrial plants using regression analysis. An analytical development is then presented showing how the general inferential sizing model arises from the nature of the classifier model. The relation between the general sizing model and the individual equations is then discussed.

Jan 1, 1984

By Robert Martin, Brian W. Stump, David P. Anderson

2We use field measurements to quantify physical processes that accompany different types of mining explosions. The data sets collected include three-component ground motion, acoustic, video and high speed film, three dimensional topography, geological and geophysical properties, design blast pattern and timing, and velocity of detonation in the explosive for individual borehole detonation times. The explosions include simple single-fired contained explosions, ones designed to bulk and fracture material and those that cast material. Our goal is a physical understanding of these sources for the purposes of optimizing blasting practices.

Jan 1, 1998

By D C. Grant, D J. Goudie, E Baird

The Scanning Electron Microscope – Mineral Liberation Analyzer (SEM-MLA) laboratory, as part of the Core Research Equipment and Instrument Training (CREAIT) network of laboratories at Memorial University, NL, Canada, has recently published efforts towards increasing the throughput of automated mineralogy systems by producing single-step trans-vertical moulds, rather than traditional 30 mm polished epoxy moulds. Due to the small particle size of iron ore grains in the -200 mesh size fraction (<75 µm), not all of the surface area on a mould is needed for measurement in achieving good statistical representation. In a new study, trimming of the excess area of a mould results in a smaller sample and increases the quantity of unique samples that can fit in a newly designed trans-vertical adapter for a FEITM MLA 650 field emission gun (FEG) scanning electron microscope. The complete analysis, using a newly designed sample block holder capable of holding 98 samples, required 57 hours of running time where each sample had an average of 33?400 particles measured and identified. The analysis was calibrated to allow for off-line discrimination of hematite/magnetite. The calculated Fe-assay values derived from MLA results were compared to those from bulk sample chemical assay. This shows the Fe assay having a correlation coefficient of >0.99 when the particle count is greater than 20?000. This study represents the most expedient method yet reported to prepare well-polished samples and analyse them in a timely manner that can allow for quicker results in process mineralogy.CITATION:Grant, D C, Goudie, D J and Baird, E, 2017. Analysis of individual - mesh iron ore samples in a single Scanning electron microscope automated mineralogy session, in Proceedings Iron Ore 2017, pp 535–540 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By G Cao, Y R. Cui, J X. Zhao, H P. Gui, G H. Wang, Z M. Wang, M M. Ren, B Li

Pyro-metallurgy is still the main process for lead production and a lot of lead direct smelting processes have been developed in recent years. All the processes will experience two steps in common. The first is the oxidisation of PbS to PbO and then reduction from PbO to Pb, furthermore, from ZnO to Zn. So, the composition of melts, especially the slag composition at reduction step change continuously. Up to now, there are few systematic results on the slag physical-chemical properties with its composition change. In this work, the typical lead direct smelting processes were analysed from theoretical and practical standpoints. The full-period slag composition and slag melting point change were compared. Especially, to the PbO and ZnO reduction steps, based on the full-period slag composition change, the slag properties were predicted. Based on dust composition and test results, the mechanism of Pb compound evaporation and its effect on practice and measurement of high PbO bearing slag physical-chemical property is discussed. It is suggested that to restrain the evaporation in practice and to obtain more accurate measurement results of physicochemical properties of smelting slag are the key problem not only to set high efficiency, energy saving process, but also to environmental pollution control.

Aug 21, 2024

By X Y. Ma, X G. Tian, P F. Zhang, T B. Zhao, Z H. Li, Z Y. Fu

This study analysed the fracture characteristics and movement process of goaf roofs under the condition of gangue backfilled mining, based on the engineering conditions of Tangshan Mine F5001 gangue backfilled working face. The inclined borehole detection method is adopted to conduct long-term and fixed-point detection of the roof stability. The distribution characteristics of mining-induced cracks in the roof are described quantitatively based on the crack density, and a similar model test method is used to assist the analysis of the roof movement under the control of gangue backfilled mining using stress sensors and digital speckle deformation field monitoring. The results show that under the condition of gangue backfilled mining, structural cracks in the roof typically appear at the boundary of rock strata. The appearance of cracks is related to the rock strata where they are located. Structural cracks appear in the form of single cracks ahead of the working face and develop into structural cracks in the goaf. The roof movement of the coal seam develops in five stages: fracture incubation, crack extension in advance, dense fracture development, steady fracture expansion, and roof stability. Separation forms the primary component of the roof subsidence, accounting for more than half of the subsidence value. The separation generally extends over a long distance along the strike, and vertical crack-intensive areas appear in the roof above the cut-off and stop line. The findings of this study provide a theoretical basis to support designs of backfilled mining and upgrading of hydraulic supports in working faces.

Nov 29, 2022

By Lei Zhang, Shining Chen, Lina Wang, Pu Liu, Benquan Fu, Jiannyang Hwang

A three-dimensional (3D) electrode reactor combined with Fenton reagent was used for advanced treatment of coking wastewater from secondary biological treatment. Effects of some key factors on total organic carbon (TOC) removal rate were investigated, and the results were compared with those of the common three-dimensional electrode reactor. Experimental results showed that TOC removal rate could reach 51.7%, when optimal operating conditions were as follows: initial pH value 3.5, H2O2 dosage 17.6mmol/L, reaction time 90min and FeSO4·7H2O dosage 3.5mmol/L. Analytical results from UV absorption spectra indicated that the organic substances in the coking wastewater were well degraded by this system, which provided good experimental basis for the practical application of this process in the treatment of coking wastewater. This can be meaningful for the treatment of other kinds of wastewater.

Jan 1, 2015

By Y. Kashiwaya, J. Yagi, P. R. Austin

The problems of global environment and resources have become important issues in recent years, and the iron and steelmaking industry is requested to decrease energy consumption and carbon dioxide emission. The improvement of efficiency of ironmaking system is one of the countermeasures for these problems because more than a half of total energy input to the integrated steelwork is input to the ironmaking system. Various approaches to improve the blast furnace process have been made. The authors examined their performances through mathematical simulations of blast furnace operation, and confirmed the improvement of blast furnace efficiency under some operating conditions. The ironmaking system consists of various processes, and the materials and the energy are transported among these processes. Thus it is necessary to evaluate the efficiency of the novel operation of blast furnace based on the ironmaking system. In this study, the balances of material and energy on ironmaking system that consists of blast furnace, coke oven, sintering and hot stove processes were analyzed. The operation status of each process in the system was adjusted according to the results of the operation simulation of the blast furnace under novel operating conditions. The analysis clarified the effect of the blast furnace operation on the energy balance and CO2 emission of the ironmaking system.

Jan 1, 2015

By Shuan-cheng Gu

Roof bed separation often occurred due to the deformation incoordination of surrounding rock following the excavation of mine roadway. Bed separation has effect on the bolts, and the estimation of the influence will directly affect the safety of support systems. In this paper, the hyperbolic function model to analyze the load transfer mechanism on the bolts was simplified as the exponential function form for easy calculation. An elastic-plastic analysis model of the bolt loading occurred by the bed separation was established. And the development low that the bed separation affected to the bolt loading was discussed. According to the parameters analysis of different separation values and locations, the influence law of the bolt loading caused by roof bed separation was summarized. Finally, the effects of bed separation were considered for the bolting design, it was able to provide a reference to the anchorage design of stratified rock.

Aug 1, 2013

By E. Vesely, A. Saxena

"SAG mill liners are designed for protecting the mill shell and providing lifting power for ore charge and grinding media. Due to the impacts from the charge and the grinding media, the liner experiences dimple, plastic deformation, strain hardening, fatigue, peening and final failure. Because of the collisional environment directly measuring such dynamical loads is extremely difficult if not impossible. In this study we tried to evaluate the liner failure risk by simulating the collisions of solid particles with mill liner using Discrete Element Method (DEM). DEM simulation has been proved to be a very useful tool in evaluation of granular flow and its impacts on the solid structure. But there are certain limits in DEM coherently, such as the number of solid elements, the computer runtime, etc. Here we first present the general feature of the particle-liner collision in terms of impact force and collision energy. Then the effects of parameter selection is discussed. Our simulations show the fatal collisional event of huge impact force is very rare and the collisional events of low impact is much more frequent. The fatal event may contribute most to the liner failure. The rarity of the fatal events may be missed in a short runtime simulation. This technical challenge combined with lacking of criterion to evaluate varying impact loads in fatigue problems may further complicate the evaluation. Should we use the largest impact force alone or we should use the more frequent events is an open question and requires more effort. In order to evaluate the quality of liner design, we proposed a relative comparison method. In the end we show the implication and application of this method in liner optimization by a work example. In particular, the effects of the charge level of grinding balls and their size on the operation performance is presented.INTRODUCTION Grinding is one of the most important and expensive steps of mineral processing. A variety of grinding mills such as rod mills, ball mills, semi-autogenous (SAG) mills and autogenous (AG) mills are being utilized for comminution of mineral ores (Gupta & Yan, 2016). Up to today, SAG mills and AG mills have been widely used to reduce operation costs and increase throughput. In an AG mill, a rotating drum throws larger rocks of ore in a cascading motion which causes impact breakage of larger rocks and compressive grinding of finer particles. Unlike AG mills, SAG mills use steel grinding balls to break ores of size quite small such that they cannot be easily broken in AG mill. SAG mill liners are designed for protecting the mill shell and providing lifting power for ore charge and grinding media. Due to the impacts from the charge and the grinding media, the liner experiences dimple, plastic deformation, strain hardening, fatigue, peening and final failure. Quality and performance of SAG mill liners play a fundamental role to enhance efficiency of grinding mills, because failure of liners is the major cause for unexpected breakdown (Banisi, Hadizadeh, Mahmoudabadi, & Eilkhany, 2006)."

Jan 1, 2019

By Axel Preusse

A high advance rate of the longwall face increases inevitably the mining dynamics within the rock and on the surface. Measures to limit the mining dynamics are the adjustment of the face advance rate to stretch the influences of mining over time and continuous winning to maintain a uniform influence of mining. This paper deals with the dynamics of mining subsidence within the range of a transmission overhead line for transportation of gasoline, diesel, kerosene, heating oil, mineral oil and other hydrocarbons. In a certain segment of the 24"-pipeline it was possible to predict, due to technical, operational and laying conditions, that undermining the pipeline would cause local stress maxima within the pipeline string. To limit these expected local stress maxima, the face advance rate of panel 497 was adjusted to the sensitivity of the pipeline towards the influences of mining. Comparison of the predicted mining dynamics, using the theory of stochastic media, with the measured ground movements led to the conclusion that the effects of dynamical influences which occurred within the range of the transmission overhead line and acted on it were low. This confirmed that the decision to adjust the face advance rate to the sensitivity of the transmission overhead line was correct (Kateloe et a)., 2002). A later relaxation cut in range of the pipeline siphon scarcely produced relaxation movements of the pipeline. The appointed sensitivity data of the undermined pipeline and the according maximum admissible face advance rate were thus correctly measured.

Jan 1, 2003

By Yong Jingrong

Based on the results of several test socketed piles in Sichuan, the mechanism of the deformation for a loaded socketed piles is investigated, and the concept of the socketed effect is proposed. The bearing capacity and settlement of socketed pile are controlled directly by socketed effect, that is an important mark different from the other types of cast-in-situ piles. According to the analysis of this effect and factors interferring it, their roles are discussed with the results of test piles. In order to increase the bearing capacity of piles, the ways and methods enhancing socketed effect are recommended.

Jan 1, 1991

By Honglei Zhang, Wuguo Xiang, Xinhao Huang, Guotao Xu, Xilai Chen

"The service behavior of refractories used in hot air pipeline for hot air stoves in a 3200 M3 blast furnace of WISCO was analyzed. The damage factors can be concluded as the poor quality of and alusite based bricks, the severe thermal shock damage, the more porosity in structures, loose bonding capability, and the unreasonable choice of materials and design of bricks. By analysis, the service life of hot air stoves can be enhanced by the measurements such as the reasonable choice of materials and their match, the use of light-weight refractories, the improvement of brick type, etc. Thereafter, the normal production operation of hot air stoves is guaranteed.IntroductionThe No.7 blast furnace of WISCO has been used for about 5 years and it was mid-repaired in March, 2012. The top phenomena of worn hot air pipelines are brick drop, breakage, severely local wear and deformation, existing hidden danger, so the worn hot air pipelines were renewed. Investigations have been done on the stove damage and design [1,2]. In order to clarify the wear mechanism, the used refractories for hot air pipelines were sampled and analyzed, the properties and structures of worn materials and reused materials are relatively studied."

Jan 1, 2013

By J. L. Carr, A. K. Smith, C. C. Jobes, G. T. Homce

"Underground continuous mining machines pose a difficult safety challenge since their operators generally work in close proximity to these machines in very restricted spaces. Intelligent software for use with magnetic proximity detection systems has been shown to accurately locate workers around mining machinery in real time. Calibrating these systems requires the manipulation of a lot of data to determine the calibration constants. Researchers have developed software to analyze, convert, and visualize data acquired during this calibration process to more accurately model magnetic fields and their interaction with the environment. This paper details the background, development, and operation of the resulting application software focusing on the utility of the graphical user interface to visualize the magnetic field calibration data. The refined data developed by this process can then be utilized by the proximity detection system to more accurately identify the location of miners working in an underground mining environment. INTRODUCTION Roughly half of the electricity consumed in the United States is produced with coal, and roughly one-third of all US coal production comes from underground mines [1]. Over the last century underground mining health and safety has seen a continuous and dramatic improvement. However, machine-related injuries and fatalities continue to be a major safety concern [2]. Every year, hundreds of miners are severely injured while operating underground mining equipment, and 39 miners have been killed in striking/pinning accidents involving continuous mining machines (CMMs) since 1984. CMMs, such as the one shown in Figure 1, are large mobile machines that are used to mechanically cut coal in an underground mine. These machines weigh approximately 40 to 50 tons, have hydraulically articulated appendages, and are capable of moving at speeds up to six feet per second [3]. Modern CMMs are remote-controlled, yet the operator and other miners are often in close proximity to the machine. Recent research by the National Institute for Occupational Safety and Health (NIOSH) reveals that the locations workers take relative to the CMM are usually influenced by visibility requirements and safety concerns [4]. The Mine Safety and Health Administration (MSHA) estimates that at least 28 fatalities involving CMMs since October of 1984 may have been prevented with proximity detection technology [5]. MSHA further estimates that proximity detection could prevent 20% of all deaths throughout the industry [6]."

Jan 1, 2016

By J. C. Yingling

[New stochastic process models are developed to calculate the probability of various fill levels in section feeders as a function of vehicle interarrival times, payloads and feeder-discharge rates. These models may be utilized to establish the minimum feeder-discharge rate necessary to prevent a feeder, with a particular surge storage capacity, from constraining the section's production rate. In addition, it is shown how the output from these models may also be utilized to calculate the probability of various flow rates at junctions in the conveyor haulage network, enabling one to size gathering belts. The model provides a basis for optimizing, (in economic terms) capacity specifications for feeders and conveyor belts in the materials-handling system by considering tradeoffs in the size of the two types of units.]

Jan 1, 1997

By C. DeW. Van Siclen

A simple mathematical description of the settling behavior of monosized particle suspensions is derived by consideration of the physical processes involved, and applied to data recently published in this journal.

Jan 1, 1995

By Anil Kumar

In underground mine production units that employ discrete-vehicle face haulage, feeders are used in the belt network so that vehicles can unload rapidly without transmitting to the conveyor network the high material flow rates that result from rapid unloading. They prevent production bottlenecks at the face, while reducing capacity requirements for downstream materials handling equipment. Similarly, surge bins may be installed at intermediate locations in the network to smooth flows from a number of upstream sources, thereby reducing downstream belt capacity requirements. This paper introduces new stochastic process models to temporally describe loading patterns from unit operations and techniques for computing the probability of various fill levels for the feeder or surge bin. These results may be used to analyze the effect of alternative bin or feeder capacities and discharge rates on the performance and costs of the materials handling system.

Jan 1, 1994

By Sunil S. Basarkar, Dilip M. Dewaikar, Rajesh H. Gajjar

"A load transfer program AXPILE was developed for simulation of the loadmovement characteristics of socketed piles of the Mumbai reg ion. This program used empirical relationships for ultimate shaft resistance at pile-rock interface recommended by Zhang and Einstein (1998). According to their recommendation, ultimate shaft resistance at pile-rock interface is related to the square-root of uniaxial compressive strength of intact socket material by a parameter C, which ranges from 0.4 for smooth sockets to 0.8 for rough sockets. Results of three instrumented pile load tests were compared with the AXPILE generated results. The comparison of analytical and field estimates of the unit shaft resistance confirm the recommendations of Zhang and Einstein (1998) on the unit side shear parameter c,, which was found to be in the range of 0.35 to 0.67.INTRODUCTIONInstrumented pile load tests were carried out on the test piles at the Bandra-Worli sea link project in Mumbai city of western India. High capacity socketed piles were required to take up loads from the superstructure. Hence, in addition to the available toe resistance, an accurate measurement of the shaft resistance in socket portion was desired. The instrumented load tests incorporated Osterbergcell (0-cell) assisted by strain gauge instrumentation to estimate the shaft resistance mobilization in the socket portion.AXPILE load transfer program was developed for load-movement simulation of socketed piles (Basarkar, 2004). The load transfer algorithm based on Coyle and Reese (1966) was incorporated in this program, which used empirical correlations and functions to account for load transfer in piles through shaft and toe resistance.This paper compares the computed unit shaft resistance from the AXPILE program with the measured values recorded from the instrumented pile load test."

Jan 1, 2005

By A. Haque

"This paper describes an improved formulation of an analytical shear strength model developed by Haque & Kodikara (2012) by incorporating the failure of regular concrete/rock joints subjected to CNS condition. Sokolovskii’s analytical solutions developed for failure stress of slopes have been found to be effective in this regard. The analytical models have been validated for predicting the shear behaviour of concrete/rock joints subjected to various CNS loading conditions. The model has been found to accurately predict the dilation, normal stress and shear stress behaviour for a regular triangular saw-tooth joint up to the peak shear stress. Moreover, the peak shear stresses of concrete-rock joints with asperity angles ranging from 5 to 27.5o compared reasonably well with the available laboratory test results.INTRODUCTIONA new shear strength model for elastic regular triangular concrete/rock joints loaded under Constant Normal Stiffness (CNS) boundary condition has been developed by Haque & Kodikara (2012). The salient feature of this model is its capability of accurately estimating the normal and shear stresses of joints with shear displacements under CNS condition by incorporating the elastic deformation of asperities. However, the shear strength model of Haque & Kodikara (2012) for the elastic asperities cannot be directly employed to predict the peak shear stress of a joint experiencing plasticity under applied loads. Therefore, the model inevitability requires articulation of an appropriate shear failure criterion simulating the boundary conditions of the loaded asperity to predict the peak shear stress and corresponding normal stress and dilation behaviour of concrete/rock joints. Sokolovskii (1960) developed a set of analytical solutions for failure stress of slopes comprising c-??soils, which can be exploited effectively to simulate the failure condition as encountered for loaded regular triangular concrete/rock joints (Seidel & Haberfield, 2002)."

Jan 1, 2015

By N. El-Kaddah, A. D. Patel, T. T. Natarajan

The phenomenon of particle migration in a conducting fluid under an applied electromagnetic force field finds its application in selective sorting of minerals and more recently in the removal of inclusion from molten metal. This paper deals with the analysis of the expulsion force and the flow around a spherical particle in crossed uniform electric and magnetic fields in .infinite and in confined medium. Analytical solutions will be presented for the electrk and magnetic fields as well as the induced flow at the limit of zero Hartmann number. The flow around the particle was investigated numerically at low and high values of Hartmann number. It will be shown the magnetic field has almost no effect on the velocity field when Hartmann number is less than 1.0. At higher Hartmann numbers the damping effect of the magnetic field was pronounced in the direction of the applied current. It is concluded that Hartmann number has little effect on the net force on the sphere particle.

Jan 1, 1999