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Updraft sintering of lead concentrates was introduced at Port Pirie in 1955 and since that time a considerable amount of investigational work has been carried out in the laboratory and on the plant with the objective of improving both the understanding of the process and its practical application.From this work it is now possible to predict trends in design and operation, which should result in capital savings and increased efficiency of future updraught plants.INTRODUCTIONOver the last 70 years a remarkable advance has been made in the method of preparing lead concentrates for smelting in the Port Pide blast furnaces of The Broken Hill Associated Smelters Pty. Ltd. (RH.A.S.). Beginning in 1889 with heap roasting, the process progressed to Ropp roasters and Huntington-Heberlein pots in various combinations, then to multiple small Dwight Lloyd (D.L.) downdraught machines. In 1940 two large 10 ft by 50 ft D.L. downdraught machines were installed, and finally in 1955 updraught sintering was ,introduced with the installation of the present 10 ft by 99 ft sinter machine.At the time this last machine was built it was the first unit of its type and thus, of necessity, an experimental machine. During the eight years it has been operating a considerable amount of investigational work on sintering has been carried out both on the plant and in the laboratory.It is now felt that sufficient information is on hand to predict at least tentatively, some of the future developments in lead sintering, whereby both the quality of the sinter and the rate of production may be improved. This will result in a considerable reduction in smelting costs.

Jan 1, 1964

By R. Hummel

When the slope angles of the southern side of the Venetia open pit were required to be flattened by some 20 degrees after an analysis completed by De Beers geotechnical engineering in conjunction with SRK, the additional waste stripping tonnage generated was in the order of some 70 million tons. The potential cost of having to move this tonnage had a significantly negative effect on the Net Present Value of Venetia Mine, challenging the viability of the third pushback and rendering a potential fourth pushback completely uneconomic. This paper details some of the innovation that went into the design and planning process undertaken to virtually negate the instantaneous effect of the flattened slope angles and the associated waste tonnage as well as further improve the NPV of Venetia Mine and bring the fourth pushback back into economic viability. This process has become known as NPV+ and is anon going exercise in waste reduction/deferment and revenue advancement.

Jan 1, 2001

By Lok M. Sharma

"Construction of a new bridge in a seismically sensitive area requires careful assessment of earthquake impact on the serviceability of the facility. Not only is the superstructure vulnerable, the foundations play a key role in the bridge’s survivability. A new bridge in eastern part of the state of Missouri in the U.S.A. is located in a seismically active area and hence subject to additional thrust on the foundations and superstructure and potential damage due to liquefaction. An eleven span bridge with foundation soils varying from shallow bedrock to over 30 m (100 feet) overburden soils were considered for the bridge support piers. Two of the bridge support bents located within the flood plain area through over 30m (100 feet) of alluvial deposits were considered most affected by an earthquake event due to the additional thrust and lateral ground spreading. This paper describes the determination of site specific seismic hazard, numerical modelling of the foundation system, and methodology of dynamic analyses, effects of lateral spreading and liquefaction potential on bridge support bents. From numerical modelling using FLAC, the increase in thrust on piers and deformations were computed to predict the behavior of the foundations.INTRODUCTIONA newly constructed bridge on route US 40 crosses the Missouri River west of St. Louis, Missouri and upstream of Mississippi River in mid-west USA. The west abutment area has near surface bedrock while the east abutment area has overburden deposits over 30m (100 feet) thick, mostly river sediments comprising of silts, lean clays and sands overlying bedrock. Softer layers of silts and sands in the east river bank area are assessed to be liquefiable during a high magnitude earthquake event. St Louis area has a potential for a high magnitude earthquake due to the New Madrid Fault some 160km (100 miles) south. The bridge foundations were designed as drilled piers, 2 m (8 feet) in diameter and socketed into the bedrock. Bents No. 10 and 11, located in the lower flood plain area of the river, are considered to be most affected by a seismic event.In order to perform dynamic analyses of the foundations, earthquake ground motion time history was developed for the specific site using a Probabilistic Seismic Hazard Analysis (PSHA) and selecting and scaling of a recorded time history. Relying on the U.S. Geological Survey (USGS) Earthquake Hazard Program for the PSHA and AASHTO Guide Specifications for LRFD Seismic Bridge Design, spectral acceleration values for the site were developed. The spectral acceleration values were for a 7 percent probability of exceedance in 75 years (1000 year return). Numerical modelling using FLAC computer program was performed. This paper presents the seismic design parameters, methodology used in the dynamic analyses, static and dynamic analyses, impact and mitigation of liquefaction on Bents 10 and 11 and the abutment fills, and effect of lateral spreading on the foundations in the lower flood plain area of the bridge. From the numerical modelling, increase in thrusts on pier foundations and estimated deformation were computed."

Jan 1, 2017

By J. O. Marsden

Parts I and II in this series of papers presented the chemistry of medium-temperature pressure leaching of copper sulfide concentrates and reviewed the metallurgical development of a process to effectively recover copper using medium-temperature pressure leaching and direct electrowinning (DEW). Key features of the process were the use of superfine grinding of the concentrate (to a P98 of 12 to 15 µm and P80 of 6 to 7 µm), pressure leaching at 160ºC and 1,380 kPa (200 psi) oxygen overpressure, DEW to produce LME Grade A cathode, recycling of the lean electrolyte to the pressure leaching step and treatment of a lean electrolyte bleed by solution extraction (SX). Recycling of the lean electrolyte provided all of the acid required to effectively dissolve copper and convert approximately 65% to 70% of the sulfide sulfur to elemental sulfur, resulting in an ?acid-autogenous? process referred to as the ?MT-DEW-SX? process. This paper (Part III) discusses the steps taken to develop and complete a large-scale demonstration of the process at Bagdad, Arizona, in 2005.

Jan 1, 2007

By Tony Lipiec, Greg Gosson

"When it comes to new mines being developed, there is a general industry consensus that most low-hanging fruit has been picked. Many projects currently in the mine development pipeline have been around for decades, but were held back because of technical challenges. Future development of these deposits will likely require access to the public capital markets, and in Canada that means providing scientific and technical disclosure on these deposits in compliance with NI 43-101. As many of these “challenged” projects have metallurgical issues, the companies that own the projects need to ensure their metallurgical Qualified Persons provide transparent disclosure regarding proposed solutions to those issues.This paper provides an overview of the disclosure requirements under NI 43-101 that are pertinent to metallurgists, and other Qualified Persons who prepare technical disclosure regarding the metallurgical characteristics of a mineral project. It lists the triggers for a technical report under NI 43-101 and Canadian stock exchange policies, and identifies the sections of the report that should involve input from a metallurgist or process engineer. It briefly outlines new civil liabilities under Canadian securities laws that increase the possible consequences for not complying with the technical disclosure standards.These materials are provided for general information purposes only and do not constitute legal advice. Readers are advised to seek specific legal advice from their own legal counsel in relation to any decision or course of action contemplated."

Jan 1, 2003

By Gustav Wafe

"INTRODUCTION The discovery in 1901 of ""gusher"" oil production at Spindletop, Tex., Tex., a salt-dome structure, led to exploratory drilling on other known domes and known domes and in areas contiguous to salt domes in the Gulf Coast region of Texas and Louisiana. Early drilling on the flanks of the domal structures disclosed incompetent 3/ shales, which flowed into the hole when attempts were made to drill through them. Often these shales seized the drill pipes and presented with equipment then in use, an insuperable barrier to deeper drilling. The obstructing incompetent shales came to be called ""heaving"" shales by drillers who attempted to drill through them. Formations of this type have hampered the penetration of the drill bit in many area in the Gulf Coast region to such an extent that the drilling of wells through heaving shale has become a major problem."

Mar 1, 1942

The interaction of flotation collectors with sulfide minerals takes place at the solid - solution interface. The electrochemistry of the processes which affect this interface are discussed. The interaction of xanthates with sulfides is an electrochemical process, xanthates being electro-oxidised to chemisorbed xanthate and dixanthogen. The role of oxygen is to provide a cathodic process to allow the anodic oxidation to occur. The hydrophobic condition of the mineral surface is brought about by the presence of the oxidised xanthate species. The action of reagents which can activate or depress the flotation of sulfides is discussed briefly.

Jan 1, 1971

By Yves-Laurent Turcotte

Notre conférencier, Monsieur Yves L. Turcotte, Vice-président et Directeur général chez Promaintech Novaxa est diplômé en génie industriel de l?Université du Québec à Trois-Rivières et détient une maîtrise en gestion de projets de l?Université du Québec à Montréal. Il est une véritable sommité canadienne dans le domaine de l?amélioration de la performance des organisations. Provenant d'entreprises manufacturières et de services, il possède plus de 20 ans d?expérience en tant que développeur de technologies, conseiller et formateur auprès d?entreprises. Il a à son actif la réalisation de mandats dans plus de 400 entreprises. Il est reconnu pour sa grande capacité d?analyse et pour trouver des solutions novatrices et profitables aux problèmes des organisations les plus complexes. Aujourd'hui, il dirige Promaintech Novaxa, une division de DMR, qui a célébré son dixième anniversaire en 2006. Cette organisation ayant des places d?affaires dans la région de Montréal, Québec et Vancouver compte plus de 50 professionnels et a une carte de visite dans 16 pays. Les axes d?intervention sont le Management, la Productivité, la Fiabilité, l?Innovation et l?Amélioration Continue.

Feb 1, 2008

By T. W. Camm

"As engineers, we are trained to use logical, rational problem solving to insure our mines operate at maximum efficiency. We tend to use the same technical approach to design safety into all mining systems. This works well for machines, but not so much for the human component. Recent insights in the field of behavioral economics provide useful ideas for addressing the fact that we are driven by emotions more often than by rational thought. Understanding the nonrational aspect of human behavior is an important piece of any safety system design. INTRODUCTION The most common economic model is based on humans making rational decisions; that given the proper information, we will make a logical, rational decision based on what is best for ourselves (Ariely, 2009, p. xviii). In many cases this is an accurate description of how we make decisions. As an engineer, I was trained to apply the precision of mathematics and logic to solve problems. As an engineering professor, I now teach this approach to bright young minds preparing them for a life of professional effectiveness as practicing engineers. That said, we are not only rational. Daniel Kahneman, winner of the Nobel Prize in Economics, describes a model for how we think (Kahneman, 2011). System 1 is the part of our mind that is fast, intuitive, and emotional; while our logical, slower, and deliberative mind is System 2. According to Kahneman’s model, System 1 runs automatically, most of what you think and do originates in System 1. System 2 takes over when things get difficult, including the application of math and logic, and the resolution (or avoidance) of conflict. As engineers, we would typically assume that we operate in System 2 mode most of the time. This is where the model becomes useful, for Kahneman points out two important aspects of the dynamic between the two systems in our mind. First, System 1 has biases, systematic errors that lead to answering questions with an easier answer (rather than a right answer) before System 2 is engaged. Second, we can be blind to the obvious, and also be blind to our blindness. Complicating things further, System 1 cannot be turned off (Kahneman, pp. 24-25)."

Jan 1, 2015

By Sean Gallagher

This report was written in an effort to provide better control measures for low back pain (LBP) and low back disability in the mining industry. There are numerous factors associated with development of LBP, many of which can be effectively controlled while some cannot. Better job design is promoted as the best method of reducing cases of LBP and can also reduce the disability (i.e., lost time from work) associated with LBP when it happens. The report draws attention to what is currently known about LBP, what the causes are thought to be, and discusses recent back injury trends in the mining industry. Research describing unique physical demands in mining, such as the capabilities and limitations of working in awkward postures, is also presented. Methods that can be used to prevent initial LBP episodes are provided, including facilities design and layout for materials and supplies, use of mechanical-assist devices, improved design of lifting tasks, and better seat design. Methods of reducing the disability associated with LBP (including workplace design, proactive return-to-work efforts, communication, and management commitment) are also discussed. The report concludes that control of LBP and disability in mining requires a comprehensive approach to limit the repetitive loading that can occur on the low back due to manual materials-handling tasks and exposure to whole-body vibration (WBV). Specific recommendations include the following: ? Successful LBP prevention efforts require a proactive program that has strong management commitment and incorporates employee involvement. ? More efficient supply handling systems and use of mechanical-assist devices can greatly reduce exposure to hazardous lifting tasks. ? Lifting tasks should be designed to minimize low back stress. Tools to evaluate and redesign lifting tasks are presented. ? Improved seat design can reduce exposure to WBV and improve posture, leading to reduced LBP risk. ? The disability associated with LBP can be reduced. Getting the worker back on the job as quickly as possible is in the interest of everyone involved.

Sep 1, 2008

By S. P. Narayan

The hot deformation behavior of Pure Mg and Mg-0.29Ce alloy were studied by isothermal hot compression tests in the temperature range of 250 - 500°C and strain rate range of 10-3 - 102 s-1 in a computer-controlled 50kN servo hydraulic universal testing machine (UTM). The results show that the flow stress of Mg pure and Mg-0.29Ce alloy increases with strain rate and decreases after a peak value, indicating dynamic recovery and recrystallization. Process efficiency was increased by nearly 10 to 12% by addition of Ce in Mg. Mg pure exhibits instability zones between 250-275°C at 10 ? 102 s-1 and 400¬500°C at 101 ? 102 s-1 temperatures and strain rates respectively, rest is the safe deformation zone. Wherein, Mg-0.29 Ce exhibits two low efficiency zones from 250 ? 300°C at 10-2? 10° s-1, 400 ? 500°C at 101 ? 102s-1 and high efficiency zone at 450 ? 500°C at 10-3? 10-1s-1. 4D process maps were generated for the above said alloys which illustrate contours of power dissipation and instability in the 3D space of strain rate, temperature and strain.

Jan 1, 2011

By Esperidiana A. B. Moura, Elizabeth Carvalho L. Cardoso, Glauson Aparecido F. Machado, René R. Oliveira

Plastics global annual production exceeds 250 million tons and more than 40% of the total plastic production is used as packaging materials. In recent years polymeric materials derived from biomass have received great attention due to scarce petroleum resources and environmental concerns. PLA is one of the most extensively studied bio-based and bio-compostable aliphatic polyesters; nevertheless, high brittleness and low toughness limits its application. Blending PLA with PBAT (Poly(butylene adipate-co-terephthalate)), an aliphatic-aromatic copolyester, was the solution found due to its high toughness and biodegradability. Differences between PLA and PBAT solubility parameter values lead to the formation of immiscible blends as well as reduction in their mechanical performance besides a poor morphology; so, 5% of pre-irradiated PLA and a previous compatibilized PLA/PBAT (EcovioTM) were added to PLA/PBAT blends in order to improve miscibility phases. Investigations were accomplished on phase morphology (SEM), mechanical properties, thermal behavior and X-ray diffractions (XRD).

Mar 1, 2017

By Z. Sun

Imposing a strong magnetic field is considered to be an attractive method to prepare materials with aligned or textured structures due to its intrinsic properties, e.g. non-contact and easily controllable. However, the nature of the strong magnetic field effect still remains unclear and further research is needed. In the present paper, the effect of a strong magnetic field on the solidification of a hypereutectic Al-Cu alloy was investigated. After magnetic field treatment, the primary phase was aligned parallel to the magnetic field direction. Meanwhile, the eutectic micro-structural constituent became elongated and thinner. A theoretical analysis was conducted to have a better understanding of the phenomena. During solidification, the magnetic Faraday and dipole-dipole interaction forces are considered to decrease the solute pile-up in front of the solid-liquid interface and modify the eutectic cell formation. The alignment of the phase is due to the shape magnetic anisotropy and crystal magnetic anisotropy.

Jan 1, 2010

The mining industry to the lay mind is one which appears peculiarly dangerous, partly because the accidents which take place are usually of a very tragic nature, and partly because other, industries claim victims more from disease than fromviolence, and their fatal nature is not advertised to the same degree so that in spite of this idea of unusual risk, it is a fact that mining will compare favourably, as regards vital statistics, with nearly all other trades requiring special training.Neverthelessthere are a larger number offatal and serious accidents occurring year by year than one would like to see, and could the deaths which take place by accident be eliminated, it is safe to say that mining would become one of the most healthy of all species of skilled labour. If we examine the accidents appearing yearly in the reports of the Mining Departments of the various colonies, it will be at once admitted that many of them need riot, and in many cases ought not to, have occurred.It is, therefore, the object of tbis essay, to pass under review the ordinary precautions which should be adopted to minimise, as far as possible, the dangerous factors whereby fatalities are brought about.

By Edwards A. B

A suite of specimens from the newly developed Black Star copper ore body at Mount Isa was made available for mineragraphic study by the Mount Isa Mines, Ltd. The specimens were selected as representative of the different phases of mineralisation found in the ore body, rather than with a view to furnishing a complete cross-section of it; and the examination has been carried out with a view to ascertaining (1) the nature, extent and association of the arsenic, antimony and possibly bismuth, minerals in the ore, (2) the mode of occurrence of silver in the ore, and (3) whether galena and sphalerite occur in minute forms well below the sIzes readily observed in hand specimens.Analyses of the January to June, 1944, mill head composites show that the proportions of the elements Ag, As, Sb and Bi in the ore are as follows:Ag 0.000013 = 0.35 oz./tonAs 0.024Sb 0:002Bi 0.0005The copper content of the mill heads ranges from 3.5% to 4.75%, the lead content from 0.03% to 0.08,% and the zinc content from 0.09% to 0.23%.MINERAL COMPOSITIONThe specimens range from massive sulphide ore, consisting of areas of chalcopyrite, pyrrhotite, and rarely sphalerite, from 1 to 3 cm. across, to fragments of extremely finely banded pyritic shale in which no minerals other than pyrite are visible. The gangue associated with the massive sulphides is chiefly dolomite, and sometimes white quartz. The pyritic shale fragments show evidence of shearing and faulting on a micro-scale, the fractures sometimes being filled with sulphides and vein minerals.The ore minerals found in the polished sections are pyrite, arsenopyrite, marcasite, sphalerite, chalcopyrite, valleriite, chalcostibite, galena, dyscrasite, jamesonite, magnetite, gold, graphite and rutile.Pyrite (FeS2)Pyrite occurs chiefly in two forms according to whether deposition took place along the bedding planes or along the intersecting faults and fractures. Deposition of pyrite along the bedding planes of dense, thinly banded shales ha,s produced a metasomatically altered shale in which the pyritic bands are from 0.02 to 0.03 mm. wide, and alternate with bands...

Jan 1, 1945

By T. G. Sieber, T. D. Tiemann

The extraction of quartz from siliceous iron ores by dissolution in sodium hydroxide solution has been described in detail in AIME Transactions. l923 data reported covered the temperature range from 230-416°F, where a continuous increase in the amount of silica extracted with increase in temperature was found. It is the purpose of this paper to describe some unexpected results of more recent work exploring principally the range of 500600°F where higher rates and greater amounts of silica extraction were antici-p ted. In brief, the experimental procedure consists in digesting the ore under pressure in solutions of sodium hydroxide, filtering the suspension and weighing and analyzing the dried residue for iron content. The amount of extraction is calculated from the weight loss or from the iron analysis of the residue and that of the original ore.

Jan 1, 1969

By Linli Wu

During the measurement of contact angle, a misty band was observed near the substrate. Hsien-Nan Ho and Shinn-Tyan Wu thought this was because the oxygen atoms on the interface migrate to the droplet surface to form an oxide band near the substrate. But from our experiments misty band appeared before the drop reach to the substrate. Theoretically speaking, the oxygen partial was the same everywhere in the vacuum furnace. So there was no condition to provide enough oxygen forming oxide. This appearance would be explained more reasonably with the optics principle. Most reflected light would be absorbed by the substrate and the light cannot reach the observation area, so the misty band formed.

Jan 1, 2006

By Warren Howes, A. B. Campbell, W. H. Ode

"INTRODUCTION The mines in the eastern part of the now active region of the Tri-State zinc district of Missouri, Kansas, and Oklahoma have unusually acid water, which during periods of moderate or no rainfall is used in the mills to replace losses from evaporation, seepage, and tailings disposal. Its use has caused difficulties by corrosion of equipment and by interference with flotation.The growing importance of flotation, which requires good water, and the increasing troubles caused by the corrosion of the milling equipment have prompted the Mississippi Valley Experiment Station of the United States Bureau of Mines, in cooperation with the Missouri School of Mines and Metallurgy, Rolla, Mo., to investigate the action of the waters on flotation and to undertake to develop means of obviating their harmful effects.The work was under the immediate direction of W. T. Schrenk, consulting chemist, United States Bureau of Mines, and professor of chemistry, Missouri School of Mines and Metallurgy, and Will H. Coghill, supervising engineer of the ore dressing section of the United States Bureau of Mines.ORIGIN OF ACID MINE WATERSRain water, carrying oxygen and carbon dioxide in solution, finds its way into the pores and crevices of the earth's crust and percolates downward through the rocks. This water and its dissolved gases exert a solvent action on many minerals, the extent of which depends upon the nature of the associated minerals.The iron sulphides are the chief sources of the 'trouble with sulphates and sulphuric acid because they oxidize so freely and contain more sulphur than is required to satisfy the iron when ferrous sulphate is formed. Galena and sphalerite may oxidize to sulphates without liberating acid. A few of the common reactions occurring in the Tri-State mine waters may be illustrated by the following equations:"

Mar 1, 1932

By Dan A. Brown

This paper describes a method of conducting rapid lateral loading tests of deep foundations in which the load is applied to the foundation with a time duration of less than one second. For purposes of this paper the loading is applied using a pyrotechnic loading system commonly referred to as Statnamic. However, the method should apply to any lateral loading system which produces a force time history with a loading duration of 20 msec to 1 second. The test provides a measure of the dynamic and static response of the soil/foundation system and must be evaluated as a dynamic loading. Interpretation of the test includes a simple single degree of freedom (SDOF) model which can account for the inertial effects of foundation mass, system damping, and static foundation stiffness. The results of the test measurements are compared with four case histories in which comparative static load test data are available, including pile group foundations and large diameter drilled shaft foundations.

Jan 1, 2007

Mercury has been used by mankind since prehistoric times. It has been, and is now, widely used in industry and medicine and has unique properties which make direct substitution difficult or impossible. At present its principal uses are for electrical apparatus, control instruments, electrolytic soda preparation, mildew-proofing paints, pesticides, and medical and dental preparations. Deposits of mercury are less common than those of other base and precious metals, but some of the deposits are very large and have been ample to meet the world's past demands. The price of mercury has had many sharp fluctuations, but in general, the limited number of producers has resulted in a more stable price structure than that of many other commodities. The United States has been one of the main producers of mercury, and from 1850 to 1961 produced 3,247,704 flasks. Yearly production since World War I1 has varied from 4,535 to 38,067 flasks. An estimate of domestic resources of mercury producible at various price ranges was prepared for each mercury mine by combining specific knowledge of mercury mineralization with estimates of potential, based on geologic information and past production history. The sum of the individual estimates for each price range is shown in a table. A parallel estimate of nationwide production potential was made from a study of past price and production relationships. These were analyzed by plotting yearly production figures against the previous year's price, expressed in dollars of constant purchasing power. An equation was fitted to the data by mathematical means and was used to extend the curve into areas of higher than historic prices. Potential production rates at various price levels were taken from this graph. The estimated yearly production rates were used to make an estimate of total potential based on the premise that production rates and reserves have a proportionate relationship. The rate of developing mercury reserves during the period from January 1944 to January 1962 is considered, and it is shown that if this rate can be continued, the mercury resources of the United States, at a constant dollar price of $500 per flask, are adequate to support a production of 60,000 flasks per year for 30 or more years. This publication contains a history and description of the mercury industry in every State which has had production and individual descriptions of all mercury properties which have reported significant production. Accompanying tables give the important facts about all known mercury occurrences.

Jan 1, 1965