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By J. M. Turnbull

THE primary objective of the young graduate, after the war, will be to obtain a suitable position within the Industry, with adequate pay and opportunity to advance. The positions available to meet this demand will depend on the magnitude and organization of the industry. The size of the mining industry, in particular, will depend on a number of factors, including depletion; new discoveries of mineral deposits; beneficiation of new kinds of mineral deposits, based on research; technical improvements, also based on research, enabling the mining of lower grade deposits; and complex social factors. The organization of the industry will depend on its control and management, which may be greatly affected by social conditions and changes, and may include a wider or a narrower use of technical services. The corresponding training or qualifications of graduates, to meet these conditions, calls for a consideration of educational requirements and facilities in relation to the conditions that are likely to occur. Some forecast of the probable future of the Industry, after the war, based on consideration of. the above factors, is necessary as a basis of discussion, since the graduate must find his place in the industry of that time, and find his work in maintaining and improving it, within the existent social framework. Social factors are pressing and? important at present and their future impact is uncertain. In considering these, a few quotations and extracts may be in order. "A new economic order, based on free access to the sources of raw materials, means free use of the world's wealth by all civilized nations" (The Pope. Also advocated by Churchill and Roosevelt in the Atlantic Charter). "Every citizen should have a voice in the conduct of business or industry which is ?carried on by means of his labour" (Archbishop of Canterbury).

Jan 1, 1943

By C. Gordon Saunders

"The ungraded-fibre mill is located at the mine site and has a rated capacity of 6,600 tons of ore input and 1,200 tons of ung1•aded fib1 •e product per day. Power for operation is obtained from a diesel generating plant located on the site, which has a capacity of 5,300 kW. The preliminary milling process consists of prima1•y and secondary crushing, drying and temporary storage of plus-1 1h -in. material. The final milling processes are two stages of crushing and three stages of screening, with air-lift separation of the fibre from the host rock. The central mill building also houses a machine shop, mill maintenance shops, a mobile equipment overhaul shop, an engine and majo1•-component overhaul shop, and a warehouse. Major changes to the milling ci1•cuits since start-up have been the addition of a larger secondary cone crusher, ct third dryer, adding a rotary distributor to the feed of the screening section and adding an automatic start-up sequence for all equipment except crushers and fans. The operation of the mill is coordinated from a central control room, where a ""mimic"" panel indicates the operation of all major units in both the ore preparation and the screening sections. Product quality is controlled by continuous sampling and frequent labo1•atory analysis, which provide data fm• the adjustment of aspirating hoods and mill feed rate. Operating problems unique to this location, and common to a sub-arctic environment, are discussed."

Jan 1, 1976

By Walter Koellner

Today?s large electric mining shovels are significant users of power and represent peak loads of more than 3.5 MW to a mine?s distribution system. The power swings during normal operation can influence the line voltage at the Point of Common Coupling (PCC). The static converters for the shovel?s motions also create voltage and current harmonics which are fed back into the mine?s power grid. In addition, shovels themselves are affected by the power quality of the mine?s distribution system. This paper introduces the use of active IGBT rectifiers, also called Active Front Ends (AFE), as alternative to conventional, line commutated SCR thyristor rectifiers. The AFEs convert the AC line input into a controlled DC-link voltage. This DC voltage is then used as input to IGBT inverters, which power the AC motors of the shovel?s Hoist, Propel, Crowd, and Swing motions. The introduction of AFEs creates the following operational improvements: i) reduction of the Harmonic Current Distortion THDi from more than 40% to less than 4%; ii) full regenerative operation; iii) the potential for line voltage stabilization at the PCC; iv) high tolerance for line voltage fluctuations; v) improved dynamic performance, and, as result vi) higher availability and productivity of the shovel.

May 1, 2001

By Yasser Mohamed

Daily field management of earthmoving operations requires quick and regular decisions for allocating available equipment to different jobs on a project. A general foreman?s day starts with matching several activities with a suitable set of available equipment to achieve the highest productivity and lowest unit cost. Usually, this decision-making process needs to be quick, and depends to a great extent on the foreman?s experience, which varies from one individual to another. Many analytical solutions with various degrees of sophistication and optimization exist to address such decisions. However, adopting any of these solutions is contingent on how accessible and easy-to-use the solution is. This paper discusses the development process of a webaccessible solution for evaluating earthmoving fleet composition and allocation scenarios. The solution relies on discrete event simulation and an optimization backend engine, but introduces the user with a simplified and easy-to-use interface that is accessible from any mobile device, and is customized to specific user?s needs. The developed system gathers most equipment and site-related input data from a company?s information systems to minimize user input. The user mainly needs to formulate equipment and job combinations and allocation scenarios (e.g. soil type, quantity, and hauling distance), according to equipment availability each day. Then the system will evaluate the productivity and unit cost estimates for each scenario, allowing the user to choose the most suitable one. It may also be used to automatically recommend the optimum solution given an available list of equipment. The paper presents the process followed in prototyping the proposed system in collaboration with a major Canadian earthmoving contractor, and customizing it to the user needs within the company. It also describes the overall structure of the developed system and its core simulation model.

Aug 1, 2013

By P. C. Lightfoot, J. M. Duke, A. J. Naldrett

"The segregation of magmatic sulphides from mafic and ultramafic silicate magmas, in many circumstances, leaves the magma with a lower-than-normal Ni/MgO ratio, which is characteristic of both lavas erupted from the magma chamber and olivine crystallizing within it. Two end members of the segregation process are discussed; i) batch segregation and ii) fractional segregation.In the former, the critical factor is the magma/sulphide ratio. Computer modelling suggests that where this ratio has been less than 1000, the magma will be recognizable as anomalously low in Ni, due to sulphide segregation, and thus a good target for exploration. In fractional segregation, the critical factors are the proportion of sulphide to silicate being segregated and the degree of fractionation.Samples believed to represent the liquid portion of komatiitic lava f lows from a series of unmineralized sequences in the Abitibi greenstone belt, Canada. Belingwe belt, Zimbabwe, and Barberton Mountainland, South Africa coincide with the sulphide-free fractionation model. They are in marked contrast to samples from the ore-bearing districts of Kambalda and Scotia. Western Australia in which distinct Ni depletion, corresponding to fractionation of olivine plus sulphide in a ratio of between 100 and 200:1 is recognizable. Ni-depleted olivines also mark the sulphide-bearing Dumont intrusion of the Abitibi belt.The Moxie intrusion of northern Maine has distinctly Nidepleted olivines, as does the nearby and petrologically related Katahdin body. In both of these intrusions, the composition of the olivine allows reasonable predictions to be made of the Ni tenors of sulphide showings within them. At Katahdin, the Ni depletion is so widespread that little hope is help out for the presence of economic concentrations of sulphide. At Moxie. the olivine compositions suggest that the best chance of economic sulphides lies in the southern lobe of the intrusion.Ni-depleted olivines also characterize certain rock units within intrusions of the Insizwa complex, Transkei, Southern Africa. Many millions of tonnes of Ni have apparently been removed by sulphides from these rock units, many more than are contained within the single mineralized occurrence so far identified at Waterfall Gorge."

Jan 1, 1984

By S. Nakamura, K. Fujiwara, S. Hirosawa, S. Tsukamoto, Y. Koshino, Y. Aruga

"In this study, hardness test, differential scanning calorimetry(DSC)and transmission electron micros copy were carried out to investigate the age-hardening behavior of Al-Mg-Si alloy with a Mg+Si concentration of 1.5mass%, and a Mg/Si ratio of 1.0. Pre-aging treatment was conducted for the solution-treated and then water-quenched specimen at 100, 80, 60, 40, 20 (natural aging), 0 and -20°C for 20min or 5h, followed by artificial aging at 170°C for 20min. It was found that when pre-aging time is prolonged from 20min to 5h, the bake-hardening response is deteriorated irrespective of the pre-aging temperature. In particular, the specimens subjected to pre-aging at 20-40°C for 5 h hardly increased the hardness with the subsequent artificial aging. From the results of DSC measurement, it was suggested that as pre-aging temperature is lowered, the amount of solute clusters formed during pre-aging, i.e. Mg-Si clusters and Si-rich clusters, is decreased, but the ratio of Si-rich clusters is increased, resulting in the deteriorated bake-hardening response.INTRODUCTIONIn recent years, Al-Mg-Si alloys have been widely used forautomotive body panels due to their excellent characteristics such as high strength-to-weight ratio and good formability. Their strength is increased not only by artificial aging during paint-bake treatment; i.e. “bake-hardening”, but also when kept at room temperature(RT);i.e. “natural aging”, in association with the suppressed bake-hardening response. Such a “negative effect of two-step aging” has been a serious problem because Al-Mg-Si alloy coils are unavoidably maintained at RT in the manufacturing process of body panels; e.g. shipping and storage. However, it was reported that pre-aging above 70°C before the two-step aging can restore the bake-hardening response, and such an improvement is related to the formation of solute clusters(Sato, 2006; Abidet al., 2010; Takaki et al., 2014; Zandbergen et al., 2015). From the comprehensive analysis by three-dimensional atom probe (Aruga et al., 2014 and 2015), it is believed that Mg-Si clusters formed during pre-aging transform into the strengtheningß"" phase, whereas Si-rich clusters formed during pre-aging act as a detrimental precursor of ß""phase. In this study, it was aimed to investigate the effect of pre-aging conditions, especially pre-aging temperature and time, on the formation of solute clusters during pre-aging, in order to elucidate the mechanism of the age-hardening behavior of an Al-Mg-Si alloy."

Jan 1, 2018

By A. Zangooi, J. A. Finch

Flotation is a separation process based on the collection of particles on the surface of bubbles. Flotation machines disperse air into bubbles using a variety of techniques. The characteristics of the bubble population are strongly affected by the selection of frother type and concentration. As metallurgical results depend on the bubble distribution, the measurement of frother concentration is vital to understand and control performance. A previously developed colorimetric technique was refined to work with low solubility frothers and to increase daily analysis rate. Field-testing demonstrated that the method is robust, reliable and accurate. As well as relating frother concentration to gas dispersion measurements, the results can be used to answer operational questions including: how well a frother dissolves, how reliable and stable frother delivery is, how evenly frother is distributed down a bank, and whether frother distributes between the pulp and froth zones. Some of these points are illustrated from plant experiences. Advances in Mineral Processing Science and Technology Proceedings of the 48th Annual Conference of Metallurgists ofCIM Sudbury, Ontario, Canada Edited by

Jan 1, 2009

By John D. Smith, Robert J. Mitchell

"There is a world-wide trend toward underground bulk mining methods employing hydraulically placed backfill. This trend is recent and therefore there is little in the literature to assist an operator in the design of backfill properties, the design of drainage facilities, the calculation of the operating forces on a bulkhead, and the control procedures considered necessary before, during and after pouring. This paper presents recommended procedures that are based on over to years of experience in the various aspects of backfilling large openings. Free-draining timber or concrete block bulkheads are shown to be a viable alternative to massive reinforced concrete bulkheads for the containment of backfill pours. Hydrostatic pressures cannot develop in backfills provided adquate drainage facilities are installed.IntroductionThe increasingly adverse relationship between mining costs and mineral values has led mining companies to develop more productive, lower-cost, bulk mining methods. This has led to the increasing use of large, more or less continuous, hydraulically placed backfill pours to enable the recovery of a higher proportion of pillar ore. The success of any bulk mining method depends on the degree of stability maintained during the stoping operations with reference to the mining rate, the performance of the backfill with respect to the per cent extraction of pillar ore, and the control of the mine structure with respect to safety and productivity. One such method has been previously described(I) where a steeply dipping orebody is being mined with a sub-level method that employs large, hydraulically placed tailings pours for delayed pillar recovery. The paper describes the rock mechanics analysis undertaken to establish the stope and pillar geometry and the approach taken to establish backfill strength requirements to prevent dilution during pillar recovery. Production with this method started in 1970 and because few, if any, large bulk pours had previously been used in- this way (judging by the lack of information in the literature), design data and criteria were needed for several aspects of the work. Methods to establish backfill quantities and pertinent ""in-place"" fill properties are described in 2, 3 and 4 in the list of references. Results of field measurements taken to establish fill pressures for bulkhead design purposes are described in 5 and 6. Laboratory large-scale model tests undertaken to confirm a fill strength design equation, which takes into account fill arching, have recently been completed. A paper describing these tests and the results will be forthcoming in the near future."

Jan 1, 1982

By A. Gakwaya, P. Vachon-Joannette, P. Gagnon, J. Lévesque

"Predictive numerical methods are essential tools for reduced development cost and improved high performance designs of modern aircrafts. Their use leads to savings in terms of design cycle time and experimental trials. Composite materials subjected to impact loadings demonstrate various damage modes such as matrix cracking, fiber breakage, delamination and, ultimately, fabric fracture. Composite laminates are extensively used in the aerospace industry, and their damage modeling is complex due to their inhomogeneity and anisotropic behavior. Damage evolution affects both in-service properties and performance of these composites. In this work, the drop-weight impact test has been simulated. Using a material model that accounts for both delamination and intralaminar damage, laminates response is analysed using numerical simulations based on 3-D finite-element models of the commercial code Abaqus/Explicit. Experimental and simulation results are compared, in terms of energy absorption and contact force. The obtained numerical results show good agreement with experimental data.INTRODUCTIONAs primary aircraft structures are increasingly being made from advanced fiber-reinforced polymer matrix composites and are in general exposed to a variety of impact scenarios (bird, hail, debris etc.), an understanding of the impact event and the performance of composite materials during impact is important in the development of new structures. This work is focussed on low velocity impacts that typically occur when foreign objects hit the aircraft during maintenance or other on-the-ground operations. These impacts can cause non visible damage that affect the structural integrity of the composite components. While for metallic structures, damaging impact events typically leave noticeable dents due to plastic deformation, in contrast, for high strength carbon fiber reinforced composites, they can deform elastically to strain levels exceeding 1% and the internal damage can often occur without the formation of a visible dent. The identification and effect of impact damage on the performance of the structure is thus of great concern to the aircraft industry as the durability and damage tolerance of these composite structures are strongly influenced by the size of detectable internal damage."

Jan 1, 2016

By T. Winkler

This paper presents elements of the Virtual Working Environment for identification of hazards occurring in the mining industry. The Virtual Working Environment includes models of machinery and models of anthropometric features. Examples are given for identification of technical hazards at the design stage using the following computer programs: Finite Elements Method, Multibody System Analysis and Human Body Modeling. One of the methods to improve work safety at the machine and equipment maintenance stage is to share design and operational knowledge in a form of an Interactive Electronic Technical Manual (IETM). An IETM is created using so-called reusable knowledge elements connected by relationships. A metamodel created in Unified Modeling Language is one of the forms for description of these relationships. The metamodel can represent, for example, interrelations between elements of repair procedures. Examples of procedures realized during the replacement of a damaged cutting bit are presented and discussed.

Aug 1, 2013

By P. J. Adams

Environmental regulations require means for controlling emissions of SO2 NOx and particulate when burning coal. The combustion of coal in limestone fluidized beds is one of the most promising techniques for the necessary reduction in emissions. Fluidized-bed firing, furthermore, offers potential economies in capital equipment. The world's largest steam generator applying fluidized-bed techniques was built under the sponsorship of ERDA and installed in Rivesville, West Virginia. This paper describes the design and discusses the start-up and development difficulties which were experienced during the period from initial operation to current readiness for commercial operation. Other developments leading to utility and industrial fluidized-bed steam generating equipment are reviewed. The future potential of this promising technique is discussed.

Jan 1, 1979

By Ken G. Kress

Syphons can be a simple, reliable and proven alternative to otherwise more complex pumping systems or low level outlet works. In a simple form they consist of a pipeline constructed over the top of an embankment or high topographic feature, connecting a source pond to a receiving pond or channel (see Photograph 1). The syphon action is initiated by removing air from the pipeline (priming) using simple devices which can be purchased ?off the shelf?. Once primed, the syphon flow rate can be controlled or stopped using conventional gate, valve, orifice plate or other devices. Repriming is not required even if the flow is stopped, provided the syphon is not drained. A limiting factor in considering a syphon as a design option is the maximum lift (i.e., vertical distance from source pond level to summit of syphon) which is approximately 9 metres, or less, dependent on syphon pipe features and site conditions. Pipeline syphons can be quickly constructed from readily available materials including steel, polyethylene and PVC pipe. They are particularly well suited to many of the unique conditions often encountered at minesites. This paper identifies situations that can sometimes be best resolved using pipeline syphons. It provides basic principles for pipeline syphon design and includes case histories of their successful application.

May 1, 2001

By J. Salazar

This paper presents a dynamic simulator of the semi-autogenous grinding operation deduced from first principles (non-stationary population balances) coupled to a Model-Based Real-Time Optimization (MBRTO) system to study optimizing strategies for an industrial semi-autogenous mill using genetic algorithms. For the design of the MBRTO both a validated first-principle steady-state model adapted on-line and a dynamic model were used to study the transient effect. The objective function considered is to maximize the ore throughput or the fine-product rate by changing the power-draw. For these purposes, these two performance indexes were introduced as fitness functions in the genetic algorithms. The three decision variables used were the ore feed rate, the water feed rate and the mill rotating velocity. The optimization problem was solved using a classical genetic algorithm with constant population. Constraints in the power draw and the filling level were handled by assigning a penalty function to the fitness function. Simulation results using industrial data for a large 1800 t/h copper-ore mill show the effectiveness of the system in finding the optimum controller set-points as a function of the process-operating constraints; mainly maximum ore feed rate, power draw and filling level. Starting from non- optimum conditions, the optimizer is able to improve the global performance index by 50% relative to a base case.

Jan 1, 2007

By C. Caballero, M. Rosales, C. León, A. Valencia, R. Fuentes, A. Moyano

Slopping is the formation of waves in the converter due to the gas injection by tuyeres. Those waves produce a premature wearing of the refractory lining of the reactor due to its great amplitude. The affected zones are the tuyere line (outlet gas from tuyeres) and the front of this line. In the present work, a theoretical and experimental study is made to develop a theory that determines the variables involved in slopping, characterizing the more important parameters of operation in the phenomenon of slopping. In addition, this theory will allow for determination of new technological alternatives of the blast injection permitting to depress the slopping phenomenon.

Jan 1, 2007

By J. Huh

Recently, there is growing trend to build the high-rise and install curtain walls. Following this trend, we developed robot for building wall cleaning work, which moves along Built-in guide rail of building. Because it moves attached at building wall for cleaning work, it can be seriously affected by potential threats, like earthquake, strong wind, malfunction, and construction error of built-in guide rail. In order to cope with those threats actively, this paper presents the Fail-Safety system. The building wall cleaning robot consists of two moving system: The Horizontal Moving System which mainly do maintenance work, and The Vertical Climbing System which transport the horizontal moving system floor by floor. We apply the Fail-Safety system to these systems. The Fail-Safety system consists of sensors to detect external situation, and, with information of sensors, give instruction for what to do. This robot system is installed with four kinds of sensors: shock sensor, infrared ray sensor, laser sensor, magnetic sensor. First, shock sensor detects external shock during cleaning work. When shock sensor detects big shock, the robot returns to starting point to inspect how damaged it is. Second, infrared ray sensor detects damage of built-in guide rail. It is to prevent destruction of robot caused by moving along damaged rail. Third, laser sensor gives notice about where obstacle is. It is for robot to avoid crash with obstacle and decrease damage. Fourth, magnetic sensor detects magnetic points, which are installed in rail at regular intervals, and helps robot to find its position, based on location of magnetic points detected. If robot is damaged by external shock and its encoder, which gives information of location to it, is not working, magnetic sensor will give information of robot?s location to robot. And then, robot regulates its velocity depending on position of it, and safely returns to starting point. The Fail-Safety system in this paper is for building wall cleaning robot to sense external threats, and prevent getting worse. Applied to this active protection system, making safe environment of maintenance work is possible for robot system.

Aug 1, 2013

By R. Gordon, J. Palich, W. Qian

The EarthProbe DCIP system deploys tightly spaced electrodes connected to a centralized data acquisition system that enables arbitrary selection of current and potential electrodes through relays. Rapid data collection (approximately 1000 readings per hour) and advanced signal processing allow for efficient use of conventional and novel arrays and the removal of natural and cultural noise. What is unique about the system is its electrode and borehole cable design, which allows seamless integration of borehole and surface measurements. EarthProbe operates in four configurations - surface, borehole, borehole-to-borehole, and surface-to-borehole (a variant of the borehole-to-borehole configuration).

Jan 1, 2011

By J. Ipinza, J. P. Ibáñez, Casas J., S. Cortés

Copper powder generated during the treatment of electro-metallurgical bleeds by reactive electro- dialysis (RED) had totally reduced the content of ferric ions in acidic synthetic electrolytes (Cu (II)- Fe (III) – H2SO4). In batch and columnar experiments 100% of the ferric ions were reduced to ferrous ions with an extremely high kinetics. A preliminary conceptual design for reducing ferric ions based on an integrate RED- Column for treatment of electro-winning bleed system is discussed. This system is able to recover simultaneously sulfuric acid and copper powder, which will reduce ferric ions. INTRODUCTION It is well known the negative effect of ferric ions in the copper electro-winning process. The increase of ferric content in the electrolyte reduces the current efficiency, i.e., there is an increase in the energy consumption, and changes the surface morphology of the copper deposit (Das, Gopala & Krishna, 1996; Vargas & Parra, 2013). The increase of the specific energy consumption due to the loss of current efficiency occurs by the reduction reaction of ferric to ferrous ions in the cathode, at the anode the ferrous ions are slowly oxidized to ferric ions (Shaw, Dreisinger, Lancaster, Richmond & Tomlinson, 2004). To control the level of iron in the electrolyte, bleeds are needed; this bleed electrolyte containing copper, sulfuric acid, cobalt, iron and other impurities normally is waster, which increased the production cost of the plant (Milbourne, 2002; Mckevitt & Dreisinger, 2009). Then, permanent efforts oriented to treat those bleeds to avoid losses of valuables components are made; among them are use ion exchange resins (Shaw et al., 2004; Mackevitt et al., 2009), chemical precipitation (Izadi, Mohebbi, Amiri & Izadi, 2017) and electrodialysis (Cortés, Ipinza & Ibáñez, 2013). The last one allows to the simultaneous recovery of sulfuric acid and copper powder. If one of the valuables obtained by treating the bleed can be used to reduce ferric ion concentration in the electrolyte could be an important asset. This issue at laboratory scale is reported in this work, the use of copper powder, generated by reactive electro-dialysis when treating synthetic acidic electro-metallurgical bleeds, for reducing ferric ions in acidic electrolytes.

Jan 1, 2019

By K Komori

Naoshima Smelter and Refinery has treated shredder residue and incinerator fly ash in Japan since 2003. As a highlight, a new incinerating and melting furnace, as well as fly ash washing treatment plant were newly constructed for pre-treatment of shredder residue and fly ash respectively, and the pre-treated materials are ultimately treated in the existing Mitsubishi continuous copper smelting and converting process line. Since wastes such as shredder residue tend to vary in size and in shape, and contain some chlorine, the installation of a new pre-treatment line was required. The combination of the new pre-treatment line with the existing Mitsubishi Continuous Copper Process line has created a highly efficient and environmentally friendly system for recovering and recycling of valuable metals that previously used to be sent to a landfill. This paper reviews the approach that Naoshima took to establish its current recycling business strategy.

Jan 1, 2007

By A. Kowalski

This paper presents methods of implementation and the added value that can be achieved by connecting personnel tracking systems and alarm-broadcasting systems. The authors point out the functions of the two systems that enable cooperation between them. Methods for connecting the systems on the surface and underground areas of mines require some intervention in both systems, so the authors point out a possible phased approach to introducing cooperation methods. Due to the fact that tracking systems in Polish mines are at an early stage of implementation, the article aims to provide new functionality, attempts to identify the needs of future users, and describes the experience of both production companies in terms of the development of cooperation methods.

Aug 1, 2013

By Ting An Zhang, Chengzhi Jiang, Xiujing Zhai, Feng Xie

The extraction and concentration of nickel from aqueous solutions by emulsion liquid membranes (ELMs) using tributylphosphate (TBP) as extractant has been investigated in this research. The emulsion liquid membrane consists of a diluent (kerosene), a surfactant (Span 80), a mobile carrier (TBP), and a stripping solution (ammonia solutions). Important factors influencing the separation process including membrane composition, feed composition, and mixing speed have been examined. The results show that more than 90% of nickel in the feed solution could be extracted by ELMs under the experimental conditions, indicating the feasibility to use the designated ELMs to detoxify nickel-containing industrial waste solutions.

Jan 1, 2014