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By A Sadough Vanini

In this paper large deformation of smart functionally graded beams with initial imperfection and under thermal loadings is considered. Smart beam consist of two types of layers. One layer is made from functionally graded materials and a layer or a set of layers from active materials that usually is made from piezoelectric materials that are bounded on the surfaces of beam. An active controller is used for controlling the deformation and stress in functionally graded layer of beam. A simple Euler- Bernoulli beam theory is used for analyzing of beam. In functionally graded layer the material property vary continuously through the thickness direction and power law model is used for the variation of elastic modulus, heat expansion and heat conduction coefficients. Poisson ratio is assumed to be constant in functionally graded layer. The effects of varying the power law constants and the Gain of controller is considered here. The results are reduced and compared with smart functionally graded beam without initial imperfections.

Oct 1, 2011

By M. Xiao Bo

In recent years, there has been a heightened interest in the hydrometallurgical processing of sulfide ores and concentrates (especially copper sulfide ores and concentrates) mostly in the USA and Chile. Currently, hydrometallurgical operations account for about 30% of the primary copper production. In the present research, the leaching phenomena of IOCG (iron-oxide hosted copper-gold) ores and concentrates were studied. The IOCG ore, which is characterized as having a predominant amount of magnetite with fine chalcopyrite, is currently the center of attention for new copper resources. Heap leaching of IOCG ore is desirable because of its low cost. However, the leaching characteristics of the ores and concentrates and the mechanisms of copper leaching require investigation. This study defines the factors, which affect the leaching operation, such as the ORP, pH and oxidizing agents. Based on these results, the optimal leaching conditions are provided for pilot column leaching test and ultimately, commercial operations.

Jan 1, 2007

By Tom Brady

A major focus of ground control research presently being conducted by the Spokane Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) is to incorporate data on weak rock masses into existing design relationships, with an emphasis on updating the span design curve for manned entries and the overbreak curve for longhole entries. Both curves were originally developed at the University of British Columbia, Vancouver, BC. The original database has been augmented by information from mines throughout the United States, Canada, Australia, and Europe. The common factor in all these mines is the presence of a weak back and/or walls. In most cases, the ore zone is the weakest rock unit and must be stabilized so that the mineral-bearing rock can be extracted safety. The current NIOSH research attempts to provide rock mechanics tools to assist a mine operator in making economic decisions that will also ensure a safe working environment. This paper documents the North American database.

May 1, 2006

By Jucheng Wang

Unplanned open stope dilution is a major cost factor for many mining operations, even though significant advances in empirical and analytical approaches for estimating stope dilution have been made. Many factors that influence hanging wall dilution are still either ignored or assessed in purely subjective terms. Undercutting the stope hanging wall on both the overcut and undercut development are well recognized factors which contribute to hanging wall instability and dilution. In many mines, undercutting the hanging wall breaks the integrity of the rock mass that may form along continuous foliation or bedding planes parallel to the stope hanging wall contact, reducing stability. This undercutting also increases the zone of destressed or relaxed rock that may potentially fall into the open stope as dilution. An approach is introduced for quantifying the effect of undercutting on potential stope dilution. An extensive database of stope case histories has been collected to look at dilution from Hudson Bay Mining and Smelting operations (HBMS) in Flin Flon.

May 1, 2002

By N. Ntakaburimvo, C. Allaire

This paper presents an innovative experimental set-up which simulates refractory degradation by separate and simultaneous action of abrasion, erosion and partially or totally immersion corrosion whether dynamic or static. It also presents abrasion testing results obtained from five commercial aluminosilicate refractories used in aluminium melting and holding furnaces. Abrasion wear was quantified by measuring the weight loss and the depth of wear, as well as by determining materials properties degradation, such as the residual rupture force and the residual modulus of rupture. Results were correlated to as- fired materials properties, such as rupture force, flexural strength, elastic modulus, toughness, and apparent porosity; in order to establish which property could be used for refractory abrasion wear prediction. They were also related to the critical length of pre-existing defects and to those generated by the abrasion process. Positive correlation was established between abrasion resistance and mechanical properties, particularly for refractory castables. For similar mechanical strength, the castables tested offered less abrasion resistance than the brick sample.

Jan 1, 2004

By C. J. Cattarello

"The Langmuir Mine is located seventeen miles south-east of South Porcupine in Langmuir Township.The property was developed as a Joint Venture between Noranda Mines Limited and the International Nickel Company of Canada with Noranda responsible for the operation of the property.The Mine came into production in June 1973 at a rate of 700 tons per day of nickel ore.MINING The mining method selected for the Langmuir Project was a sub-level retreat method. This consisted of driving sub-levels longitudinally in the ore body at 35 foot, intervals with the sub-levels being connected by a ramp from each main level for the use of trackless mining equipment.GENERAL GEOLOGY OF THE LANGMUIR MINE The deposit is situated about 1,000 feet west of the shore of Carmen Bay at the south of Nighthawk Lake in Langmuir Township. The area is underlain by andesite and rhyolite flows with iron formations which are intruded by gabbro, diorite, peridotite and late precambrian diabase dikes."

Jan 1, 1975

By He Zhexiang

The settlement properties of tailings modified by flocculants were investigated at the Shizhuyuan Mine, with the aims to screen for the most effective flocculants and the optimum dosage rates for tailings sedimentation. The settlement rate was used as the indicator of effective tailings sedimentation. Calcareousness and three polyacrylamides (F1, F2 and F3) were selected for settlement property evaluation. The results proved that sole use of calcareousness or any of the polyacrylamides had no apparent effect on the tailings sedimentation, while a remarkable acceleration of sedimentation could be observed with a combined addition of calcareousness and polyacrylamides, among which the addition of polyacrylamide F2 together with calcareousness is the most effective. The optimum dosage rate of F2 and calcareousness is 50g/t and 3kg/t respectively. The density of tailings slurry has an effect on sedimentation at the early settlement stage, with lower density generating quicker initial settlement.

May 1, 2007

By P. B. Marchant

"Based on laboratory and pilot scale continuous biooxidation of complex sulphide concentrates, commercial processing design and scaleup considerations are discussed. Capital and operating cost estimates for commercial biohydrometallurgical operations are summarized and potential applications of biotechnology are discussed. Biooxidation as an oxidative pretreatment alternative to enhance precious metals extraction from refractory sulphide concentrates in stirred tank reactors has received considerable attention recently due mainly to advances in the practical applicability of the process. Biooxidation of sulphides is certainly not a new process, however, application and control in large scale hydrometallurgical operations to treat refractory sulphides remains conceptual and the limited data available is restricted to relatively small laboratory and pilot scale operations. It is the intent of this paper to indicate scaleup and plant scale process design considerations for commercial bioleach circuits, based on recent operating experiences with laboratory and pilot scale continuous bioleach systems. An indication of the expected range of applications will be presented parameters for optimization will be discussed."

Jan 1, 1986

By Zhigao Xu, Ruan Chi, Zhenyue Zhang, Yaoyang Ruan, Zhengyan He

Thorium is frequently the main radioactive element in rare earth ores and is a resource that can potentially substitute for uranium. Thorium must be separated from rare earths in order to obtain products with low radioactivity. There are abundant resources of thorium in the rare earth ores in China, especially in Baiyunebo mixed ores. As an associated element coexisting in rare earth ores, thorium is, or can be, separated from rare earth concentrate, iron concentrate, as well as from waste water and slag to achieve recovery of thorium. The methods of separation include ion exchange resin, liquid-liquid extraction, and liquid-solid extraction. TBP extraction has been the main method applied to separate thorium by domestic and foreign scholars. This paper presents a comparison of different processes for the separation of thorium from rare earth ores, especially Baiyunebo mixed ores, single bastnaesite and monazite ore, and provides suggestions for the future recovery of thorium resources.

Jan 1, 2014

By C. Bazin, D. Hodouin, M. Ounpuu

Sensors are now available in mineral processing circuits to monitor pulp flowrate and density, as well as ore characteristics and other process variables. The amount of information provided by these instruments is considerable but in many cases poorly exploited. This paper gives the results of the application of time series analysis techniques to signals generated by the sensors installed on an industrial Pb dezincing flotation circuit in New-Brunswick. Autocorrelation and cross correlation functions appear to be interesting tools for a preliminary circuit analysis, however the calibration of single input single output discrete transfer functions using collected sensors signals leads to conflicting results. For this reason a phenomenological approach, based on the kinetic and transport properties of the flotation process, is also considered. It has several advantages over the empirical transfer function modelling but also limitations in its applicability to industrial processes. A combination of the transfer function and kinetic modelling approches appears to be a promising avenue for better process modelling and control.

Jan 1, 1985

By Zainelabdin Khalid Zainelabdin Elfaki

The influence of partially replacing cement with marble waste on the workability and compressive strength of concrete bricks was investigated. Three replacement percentages, 10%, 20% and 30% weight marble waste, were used with different curing times of 7, 14 and 28 days. Two specimens were prepared for each percentage and curing time. For this study, marble powder from the Mining House Company in Saudi Arabia was used. It was observed that the replacement of cement in Concrete brick with marble waste enhanced the loading strength and the workability of the prepared concrete bricks. It was also observed that 20% replacement of cement with marble waste was the best replacement percentage compared to the other replacement percentages tested. Marble waste from manufacturing companies, either in powder, sludge or slab form, has negative impacts on the environment. In contrast, reusing marble waste has both economic benefits (i.e., selling the marble waste) and lessening the need for raw resources.

Jan 1, 2014

By T. L. Lee, D. Y. Tan, J. Mi

Considerable progress has been made in studying the mechanism and effectiveness of using ultrasound waves to manipulate alloy solidification microstructure, However, uncertainties remain in both the underlying physics of how microstructure evolve under ultrasonic waves, and the best technological approach to control the final microstructure and properties. We used the ultrafast synchrotron X-ray phase contrast imaging facility housed at the Advanced Photon Source, Argonne National Laboratory, USA to study in-situ the highly transient and dynamic interactions between the liquid metal and ultrasonic waves/bubbles. The dynamics of ultrasonic bubbles in liquid metal and their interactions with the solidifying phases were captured in-situ for the first time. The experiments were complemented by the simulations of the acoustic pressure field, the pulsing of the bubbles and the associated forces acting onto the solidifying phases, providing more quantitative understanding for using ultrasound to control the growth of dendritic grains and to enhance grain multiplication effects for grain refinement.

Jan 1, 2014

By Rodrigo A. Marinho

Erratic high grade values are as common in Nature as they are a source of problems for resource estimators. In some highly erratic metal deposits, less than 2% of the drilling samples can represent more than 10% of the total metal in the blocks and they are associated with a high risk level. There is a risk of local overestimation but also of global overestimation, with the high grades being projected over too large a volume. Capping or restriction of these outliers control is being widely used in the industry and commonly applied in resource estimation for the last three decades. The primary purpose of this paper is to present and describe the most applied methodologies for restricting the extrapolation of high grade samples and discuss the results based on a theoretical simulated model. Additionally, this paper demonstrates the economical impact associated with the high-grade and the project risk profile associated with each method.

Oct 1, 2009

By Robert W. Plummer

"This paper describes the use of Geographic Information Systems (GIS) as a tool for mineral exploration by using the Eskay Creek area of northern British Columbia as an example. Data entry, analysis and output are discussed. Examples of some of the capabilities of the technology are presented.The main benefit of the technology is being able to perform complex and sophisticated searches of large and diverse data sets to highlight exploration targets. A GIS is a powerful data management tool that can be used in mineral exploration. It is a computer based system that is designed for the collection, storage and analysis of objects and phenomena where geographic location is an important characteristic. The main function of the GIS is to produce information for the geologist from a variety of sources (geology, geophysics, geochemistry, mineral deposits and so forth) quickly and efficiently. This allows the geologist to examine large amounts of data in a fraction of the time than can be done using conventional manual methods."

Jan 1, 1992

By Joseph H. Harris

Shebandowan Mine presents a unique opportunity for the mining industry to demonstrate its willingness and ability to use electrical energy effectively. The mine is a typical 250D-ton/day operation supplied by a i5-MVA power transformer. it is a recent, up-to-date design and operates on a four-day/week, two-shift/day basis. The paper outlines an energy profile based on historical data. It accurately describes the individual and total energy input For: (1) production and non-productive junctions; (2) production and down-time periods; (3) peak and average activity levels; and (4) principal energy utilization equipment. A comparison is then made of production data to electrical data, and production and electrical data to design data. The paper concludes that energy management has an important benefit for the mining industry by assisting in maintaining a competitive operation through reduced costs and fewer production slow-downs in the event of energy shortages.

Jan 1, 1979

By Norman J. Tienkaivip, Christopher J. Preston

"This paper describes the use of electronics for physical measurement and computer analysis in both open-pit and underground mining operations for the ultimate purpose of optimizing production blasts. Techniques in monitoring single borehole blasts using both pressure and vibration sensors to establish in-situ dynamic rock properties are outlined, including characterization of multiple borehole production blasts with regard to stress generation.Once field derived measurements are computer analyzed, they are channelled as input parallel to other data, such as the explosives thermochemical performance properties generated by a sophisticated computer program called ""HT-65"" into BLASPA . BLASPA, a blast simulation computer program, then couples these input with a mathematical model which defines the blasting processes. Aspects such as the blast geometry, explosive loads and distribution, hook-up, and costs are studied. The final output table gives specific blast performance or quality factors for each blast procedure. These results are then easily compared and rapidly optimized to achieve maximum performance at lowest blasting and drilling cost."

Jan 1, 1984

By Pierre Boulanger

This paper describes a generic technology for modeling in real time the various operations of surface mines. Based on various sensor fusion techniques and high-speed network, a virtual reality model of a mine capable of representing not only static infrastructures but also mobile equipment such as trucks and excavators is created. The modeling technique deal with a wide range of sensors such as survey data, satellite pictures, ore concentration, machine condition indicators, video, sound, real-time GPS locator, range sensor, etc. The model created allows for every piece of information to be displayed in context allowing for a better temporal and spatial correlation of events by mine operators, planners, and supervisors. Syncrude, a Canadian mining company located in northern Alberta, is planning to use this technology, not only to understand oil sands mining processes better, but also to give decision-makers better access to the timely, accurate information from the field that they need to make informed decisions.

May 1, 2001

By C. Larsen, E. Gratch, B. Flintoff, R. Bradburn

"In 1973 Brenda Mines Limited first investigated the potential use of a process computer to aid in the development of a control system for the concentrator grinding circuit. This initial study and its results are reviewed (1) in a previous paper.Since that time the computer system and its applications have been expanded. After the initial success of grinding circuit control, a second process computer was purchased to function as a back-up device. The two processors are currently operated in a foreground-background mode which allows extensive use of the computing facility for engineering and development work as well as operator training.Because of the relative ease of expansion, the computer has been incorporated into a flotation control system as well as an electrical peak power savings program.It is the purpose of this paper to review the successful application:; of the process computer and to indicate applications which are envisaged for the future."

Jan 1, 1978

By L. R. Wilkinson, W. J. Howarth, G. J. Wenk

Over a period of three years, a cooperative program in Australia has resulted in the development of radioisotope immersion probes for the on-stream analysis of mineral slurries. Two basic probe types are now available on a commercial basis - fluorescence and absorption probes - and within each type there are a number of variations so that optimum sensitivities can be obtained for elements with atomic number greater than titanium (22), thus covering most metals of interest to modern metallurgy.

Jan 1, 1973

By S-E. Vandat

The goal of this work was to select an appropriate electrode for dummy load of diesel engine in fully salt-water in the DESA factory. The electrochemical corrosion rate of general structural steel, commercial pure aluminum and cathode copper calculated as weighting, volumetric and commercial in fully salt-water by city power. After several tests and then applying the fuzzy logic method, it was determined that general structural steel is the best selection for this purpose.

Jan 1, 2005