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Lead Removal from Contaminated Soils with Chelating Agents

Sep 13, 2010

By E J. Hofmann, J E. Hofmann, A J. Hofmann-Fritz

"With its Head Quarters in Perth, global heavy engineering company Hofmann Engineering is one of the largest family owned engineering companies in Australia. The company has pioneered a number of new manufacturing processes and design improvements for components of large comminution equipment.Some of these innovations are: Innovative design improvements of high pressure grinding roll (HPGR) forged steel tyres. Hofmann Engineering has developed unique patented tungsten carbide stud and edge protection designs which improve wear life and introduce quick and cost effective replacement options to further extend the life of the tyre. Development of forged fabricated mill heads using rolled and welded high tensile steel plate as an alternative to cast conical mill heads. Establishment of Australian capability to manufacture and export up to 42 ft. (12.8 m) diameter SAG mill shells. Techniques for fast track, product improved replacements of cracked or damaged mill gears, including in situ profile & wear measurements of girth gears using portable coordinate measuring machine (CMM) technology, forged rim steel and induction hardening technology. Gear and pinion mechanical drive designs to 24 MW or higher for SAG mills of 38 ft. to 42 ft. (11.6 m - 12.8 m) diameter as reliable alternatives to gearless drives.The paper presents case studies from the Australian heavy manufacturing facilities of Hofmann Engineering on large, high powered equipment for both the domestic and export markets.CITATION:Hofmann, E J, Hofmann, J E and Hofmann-Fritz, A J, 2013. Australian innovations in high pressure grinding rolls and large grinding mill manufacture, in Proceedings MetPlant 2013, pp 141-151 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 15, 2013

By Milton Camino

El presente texto describe los antecedentes geológicos del yacimiento orogénico El Gigante, el cual presenta una mineralización filoneana del tipo relleno de fracturas asociada a estructuras de un lineamiento principal NW-SE. posicionándose como una de las franjas metalogenéticas de oro más importantes de la región y del mundo. De forma que se busca difundir los últimos resultados de la exploración a través de los nuevos descubrimientos en profundidad y los nuevos sistemas de vetas al borde Este del Batolito De Pataz. Así como formular un modelo que integre geología, mineralogía, cronología y geoquímica del yacimiento El Gigante, que permita mejorar el entendimiento de los procesos de formación de los yacimientos orogénicos de la franja metalogenética de Pataz y oriente al descubrimiento de nuevos recursos minerales.

Oct 21, 2015

The mining industry has recognised for some time the importance of supporting programs which serve to educate the Australian public about the socio-economic benefits of mineral resource development. More recently, industry leaders have realised that the future development of the industry will depend on attracting sufficient young people to commit to a career in the industry. Apart from lending support to the traditional education institutions in Australia, the industry now has the opportunity to participate in the development of education programs in museums. Whilst historic, mining-related theme parks such as Sovereign Hill and Coal Creek in Victoria serve very effectively the objective of relating past mining activities to the socio-economic development of Australia, there still exists the need to provide a facility which, under the same roof, excites interest in geology, mining, mineral processing and the role of minerals and energy in modern society. The redeveloped Geological and Mining Museum (the "Mining Museum"), which is located in The Rocks area of Sydney, meets this objective. With the central themes of formation and transformation this new Museum, which aims to be the best of its type in the world, will use modern museum exhibit techniques and the resources of the Minerals and Energy Information Centre to educate the community including teachers and school children. In the best tradition of museums, outstanding mineral and other collections will complement a comprehensive range of interactive, high technology exhibits which will include a number of exploratory "hands on" facilities. Australian companies are joining with Government to fund this exciting new museum. There is still a need for industry professionals to realise that a modern "mining" museum is no longer just a repository for objects of mining heritage but is also an important centre which serves as an important educational and public relations interface. The Education Section of the new "Mining Museum", which is linked closely with the new Minerals and Energy Information Centre, will be working closely with appropriate mining-related Tertiary institutions to develop specific career programs aimed at secondary students who wish to pursue a career in the mineral resource industries.

Jan 1, 1989

By Craig Naudé

"An enhanced gravity concentrator was installed in conjunction with an Intensive Leach Reactor at the Sadiola plant in Mali last year and commissioned in Dec 2007.There has been much debate over the years as to the effect of gravity concentration on overall plant performance. The late Dr Laplante suggested that for every 10% of gold recovered by gravity, there was a corresponding 0.1% to 1% additional overall plant recovery. The results at Sadiola are consistent with this hypothesis with an overall 4% gain in plant recovery.With total gold recovery of 12% in the gravity section, grades are increased from 3.54g/t in the gravity feed to an average of 2 600g/t in the concentrator feed to the in-line reactor. The recovery of gold in the in-line reactor is in excess of 98.5%.This paper discusses the background to the project, the laboratory testwork prior to the equipment selection, the operational results of the system, as well as the benefits of the future application of high mass yield centrifugal concentrators in base metals, sulphides and industrial minerals. Bench scale, pilot scale and plant practice examples are also presented.INTRODUCTIONBesides picking nuggets off the ground or out of riverbeds, gravity concentration is arguably one of the oldest methods of recovering gold. In circa 6000BC people discovered that gold can be found behind the rocks and in depressions of creek beds. By placing rocks in a stretch of channel with the proper slope the first sluice is built, probably around 4,000 BC, and this method is still practiced today."

Jan 1, 2009

Disasters are often tragic outcomes of high-risk technologies such as mines. In Australia, more mines are being developed every day, and the risk of disasters is ever increasing. No matter how effective our conventional safety devices are, there is a form of accident that is inevitable. These relate to accidents that result from æinteracting failuresÆ in a way that could not be foreseen by the designers. In so-called ætightly coupled production systemsÆ (processes that happen very fast, such as on a high producing mine) the risk is even higher and our risk controls mostly introduce some sort of a technological fix. While we are at the one hand attempting to control the risk, we are also introducing another level of complexity. Are we really controlling the risk? This is one of the fundamental questions that will be addressed in this paper: Do we have the ability within the mining industry and other industries to effectively prevent these catastrophes, or are we, on the contrary, faced with an increasing risk as a result of increasing complexities of our technology, management systems and practices. This paper will contend that perceived improvement in risk control is an illusion of activity, and that the likelihood of mining catastrophes may be exponentially increasing. Although the paper focuses on the mining sector many aspects may be applicable across a range of industries. This paper will further contend that we are applying the right solutions to the wrong problems. Our focus is technological and procedural, while our problem is one of production cultures ripe for error and failure.

Jan 1, 1999

By R. H. O. Wagner

"This paper describes the bench testing, pilot plant studies of alternative flowsheets, to determine the feasibility of gold recovery, by carbon in pulp extraction, in the Schumacher Mill gold flotation tailings. The economics were calculated based on pilot plant recoveries and actual industry operating costs.The economics of the carbon in pulp treatment of the gold flotation tailings were not justifiable. The economics of desliming the gold flotation tailings followed by carbon in pulp treatment were marginal, but favourable. INTRODUCTIONPamour Porcupine Mines, Limited is a gold, silver and copper producer located in Timmins, Ontario. In 1983 the head grade of Pamour's gold ores averaged nine one hundredths of a troy ounce of gold per short ton.Pamour operates two area mills to concentrate the gold ores. Free milling gold ores are processed at the Pamour One Mine mill, whereas the refractory carbonaceous gold ores, and complex gold, silver, and copper sulphide ores, are processed through the Schumacher Mine mill.The complex Schumacher mill feed ores do not all react favourably to flotation methods, consequently this study was commissioned to investigate the feasibility of the carbon in pulp cyanidation of the Schumacher mill gold flotation tailings. These tailings contain ten to fifteen percent of the gold in the mill feed. During the study period, the average grade of the Schumacher mill flotation tailings was nine one thousandths of a troy ounce of gold per ton, or one quarter of a gram of gold per metric tonne."

Jan 1, 1984

By Z. Lin, M. Isac, R. I. L. Guthrie

The kinetic and thermodynamic efficiencies of chromium recovery from the slag in an AOD process during the slag de-oxidation period with ferrosilicon is a complex process affected by slag basicity, temperature, the dissolution kinetics of the reducing agents, and intermixing of the slag/metal/alloy addition phases within the vessel. The present work focused on a study and simulation of the fluid dynamics and mixing behaviour of ferrosilicon additions in the AOD process for the production of stainless steel. In order to visualize the mixing behaviour, a two dimensional slice model of an AOD vessel was first built and filled with ZnCl2solution and then covered with silicone oil in order to represent the bulk liquid steel and slag phases, respectively. The injection of argon/oxygen process gases was simulated using air or helium. Particle trajectories and intermixing of the phases was monitored with a high-speed camera. To simulate the 75FeSi additions, glass spheres were used. A three-dimensional version of the AOD model was then constructed in order to confirm the adequacy of the slice model. Similar particle mixing behaviour was observed. Both models demonstrated that the ascending gas/liquid plume created two asymmetric mixing zones: a smaller rapidly re-circulating mixing zone adjacent to the side-wall locating the tuyere(s), and a larger mixing zone in the main part of the vessel. The process efficiency during the reduction period is governed by the thermal behaviour of ferroalloy as well as the mixing efficiency in the main large mixing zone. To enhance the recovery efficiency for chromium, small Fe-Si particles are suggested, given their wide distribution within the slag phase, and their large interfacial areas and rapid melting times for Cr2O3reduction from the slag. Keywords; modelling, ferrosilicon, chromium oxidation, AOD steelmaking.

Jan 1, 2004

By Brad Hewitt, Jeff Belke

"Murrin Murrin Operations has not had a successful beginning. Numerous reliability and operability issues many of which are the result of design decisions have been addressed through mechanical and operational changes and the CCD circuit is no exception. Four design aspects of the CCD circuit that have caused and continue to cause operational problems are:1. the inclusion of solution neutralisation gypsum in the CCD circuit feed which was designed solely for HPAL residue without proper investigation of its impact on the achievable underflow density and resulting wash efficiency;2. the decision to construct the thickener base from thickened solids;3. the lack of redundancy in the overflow, underflow and tailings pipe work; and4. the lack of thickener operational flexibility in the central rake-lift and feedwell dilution system.In November 2002, the lack of operational flexibility in the rake-lift and the feedwell dilution system through mechanical modification as follows:•, CCD1 has a modified rake mechanism that now allows central vertical lift of 600 mm;•, CCD1 has forced dilution using the Outokumpu Turbodil® technology and replacing the E-Duc® technology of Eimco;The decision to install, the installation and the results of the CCD1 rake-lift mechanism and feedwell dilution system are discussed in this paper. The installation was justified on improved operational robustness and an increase in the in the underflow density of 1 per cent (per cent w/w). At approximately the same time process modifications in the solution neutralisation circuit were implemented and these changes altered the rheology of the slurry reporting to CCD1. Since the modifications to CCD1 and the solution neutralisation circuit, the CCD circuit has averaged a 2 per cent improvement in the circuit underflow density.The CCD1 modification was completed on time and mechanically has performed well. From a risk point of view, the central rake-lift and Turbodil®dilution system add a degree of freedom and robustness to CCD1 operation that has extended the range of operational confidence. In this respect, the modification has been a success and is complementary solution neutralisation improvements."

Jan 1, 2005

By Catherine Aimone-Martin, Mary-Alena Martell

Whole-structure and mid-wall responses of 33 non-traditional structures to surface coal mine blasting were characterized. Eighty-nine blasts were conducted at 11 mine sites throughout the U.S. to measure blastgenerated dynamic response of structures typically found in the proximity of surface coal mining. Structures selected for this study include log-type, manufactured (single- and double-wide trailers), “mine camp”-type, adobe, and stone. Traditional acoustic microphones, t&axial (ground) and single component (structure) velocity transducers were used to record airblast, ground motions, and structures response time histories with a common time base. Wall crack displacement gages were used to record static and dynamic movement of existing drywall cracks. The relative responses of selected “atypical” structures to blast vibrations and nonblasting causes of structural stress, including natural forces, environmental effects, and human habitation, are compared. The purpose of this study is to document and compare vibration characteristics of structures that were not included in previous studies conducted by the U.S. Bureau of Mines and others in establishing the widely adopted safe level blast vibration criteria in the U.S. An important objective of this study is to outline an evaluation process including structure uniqueness relative to cracking susceptibility.

Jan 1, 2002

By Glenn Kosick, John Starkey, Glenn Dobby

"A practical new test has been developed for SAG hardness determination. Using two kilogram samples of minus one inch diamond drill core or crushed muck samples, the Starkey SAG Test has been shown to give accurate predictive information which directly relates to on-stream SAG mill performance. Typical results and test criteria are discussed in the paperAchievements to date include:• Identification of hardness profiles and the location of hard and soft zones in a large ore body.• Accurate prediction of the hardness of a bulk sample by using an adjacent diamond drill hole.• Derivation of a plotted curve relating pilot plant power to laboratory relative hardness.• Demonstration that for every test done to date, the Starkey SAG Test produced a product size distribution identical to that produced in a pilot plant or full scale plant SAG operation.This test can now be used for blast hardness monitoring and short term control of mine production in existing plants and for identifying the proper locations for bulk samples in new projects. In addition, new SAG mill design can now be rationalized in a low cost way to eliminate unforeseen production shortfalls.IntroductionThis paper is presented to introduce the Starkey SAG Test, a practical new laboratory tool for measuring the relative hardness of small ore samples in a semi-autogenous grinding (SAG) environment. The test was first designed for use on diamond drill core samples during the prefeasibility stage of new mining projects, to provide new information about the ore body at reasonable cost. It is a new tool and does not replace existing pilot plant test requirements.The test will also be useful for throughput prediction in existing SAG plants by assisting in short and long term mine planning, where forecasting of metal grades and milled tonnage is used to control mine profitability. Because in-plant hardness testing has previously been unavailable on small samples, this test offers exciting possibilities for SAG mill operations where hardness variation is or could be a problem.The Starkey SAG Test provides the following benefits to the mining industry"

Jan 1, 1994

By R. Duval

El presente texto se basa en la estadística clásica del muestreo que indica los lotes de materiales minerales al granel y de yacimientos mineros a los ingenieros. Este sistema describe las fallas que afectan los resultados de los muestreos cuando se emplea métodos, sin las debidas precauciones. Así también se muestran los tres principios esenciales que son la base del muestreo simple al azar, donde se funda toda la teoría estadistíca del muestreo

Jul 1, 1971

By Antonio De Biase

In October 2006, a 7m Double Shield TBM, boring through very poor volcanic formations, was pushed back by fluid mud, which presence had not been detected during previous field investigations, due to the high covers characterizing the majority of the tunnel axis. The present work describes the investigations made to gain better knowledge of the conditions in front and all around the TBM, the special measures implemented, the exploratory and bypass tunnels excavated, the extraordinary occurrences came true during the execution of these tunnels, the drainage campaigns, the design of the chamber excavated to free the TBM, the dismounting and restarting of the TBM.

For many years the scrubbing of roaster gas carrying sulphur dioxide has been carried out at the plant of the Electrolytic Zinc Co. of Australasia Ltd. at Risdon, Tasmania, using long horizontal tubes. in which the gas stream crossed a shower of water. In order to provide for increased roaster capacity, it was evident that additional gas scrubbing capacity would be required to prevent pollution of the atmosphere.This provided an opportunity to review the whole operation of gas scrubbing and an investigation was initiated to determine the characteristics of a counter-current type of scrubber. It was hoped that a change to this type of scrubbing would also reduce the sulphur dioxide concentration of the gas delivered to the atmosphere to a negligible amount. This, paper outlines results obtained from an experimental tower which was operated under a wide range of conditions, the packing height, gas flow, water flow, water temperature, and concentration of S02 in inlet gas being varied independently. A description is given of the leading features and operating characteristics of the plant units, which are designed on the basis of the experimental results. Operation of the new scrubbing system commenced on October 5th, 1948.THE PROBLEMThe gas which is handled carries S02 which may vary in concentration from 2% to 5%, and reaches the scrubbing system at a temperature of approximately 180 deg. C. An appreciable amount of suspended material accompanies the gas which has passed the cyclone system.

Jan 1, 1949

By Jackson R. Pressley, M L. Hopkins, R E. Danell, N T. Moxon, Andrew Bowman

Efficient and cost effective blasting is achieved by closely matching the explosive energy to the strength of the material in which it is being used. Although there are many empirical relationships wich approximate this situation complete the blast optimization can only be achieved by quantitatively assessing explosive/rock interactions and explosive performance. The performance of an explosive is essentially governed by its velocity of detonation or the rate at which the detonation wave travels through the explosive column.

Jan 1, 1991

By R. E. Old

Through the use of pressure and production records, formation properties and bottom-hole sample data, the performance of an oil reservoir may be studied analytically to define and evaluate the natural forces acting on and within the reservoir. Use is made of material-halance methods and the equations for natural water encroachment. to estimate reserves. Methods for calculation of pressures are given. A study of the Jones sand, Schuler field, Arkansas, has been made and is given here to illustrate the value of the methods discussed. Introduction With the decreasing rate of discovery of new oil reserves, attention is necessarily focused on the efficient development, evaluation, and production of existing reserves. From the nation's viewpoint, the necessity of conserving resources is obvious. From the operator's viewpoint, the problem is to lengthen the period of profitable operation, in an attempt to increase the return on his investment. To do this the operator must take advantage of the natural forces acting on and within the reservoir. Natural water encroachment, the nemesis of profitable operation in the past, can be and is being harnessed to produce a greater oil recovery during the stage of flowing production. Proper evaluation of water encroachment rates and a fuller under- standing of reservoir behavior dictate the appropriate production procedures. Complacency in hit and miss production is obsolete. Oil production must and will approach the efficiency of other businesses, such as manufacturing. A manufacturer will not place an article on the market until he has fully investigated the processes involved, additional investment in equipment, costs of production, and expected profits. These may be modified by actual experience at a later date, but at least he begins with an idea of expected return. It is just as logical that an oil operator should investigate these same factors during the development and the early period of production of an oil reserve. The complexity of the problems existing in oil reservoirs should not be underestimated. Conversely, they should not be regarded as insoluble. Many completely defy solution, but there are others that can be solved completely or attacked intelligently to yield approximate results. The petroleum engineer has many tools, both figuratively and literally, at his disposal. Physical data such as core analyses, electrical logs, bottom-hole sample analyses, and bottom-hole pressures are accumulated extensively. Advances in the analytics of fluid flow have kept pace with the advances in measurement of physical data. It is the purpose of this paper to show how some of these records may be analyzed to define certain phases of reservoir behavior.

Jan 1, 1943

By R. E. Old

Through the use of pressure and production records, formation properties and bottom-hole sample data, the performance of an oil reservoir may be studied analytically to define and evaluate the natural forces acting on and within the reservoir. Use is made of material-halance methods and the equations for natural water encroachment. to estimate reserves. Methods for calculation of pressures are given. A study of the Jones sand, Schuler field, Arkansas, has been made and is given here to illustrate the value of the methods discussed. Introduction With the decreasing rate of discovery of new oil reserves, attention is necessarily focused on the efficient development, evaluation, and production of existing reserves. From the nation's viewpoint, the necessity of conserving resources is obvious. From the operator's viewpoint, the problem is to lengthen the period of profitable operation, in an attempt to increase the return on his investment. To do this the operator must take advantage of the natural forces acting on and within the reservoir. Natural water encroachment, the nemesis of profitable operation in the past, can be and is being harnessed to produce a greater oil recovery during the stage of flowing production. Proper evaluation of water encroachment rates and a fuller under- standing of reservoir behavior dictate the appropriate production procedures. Complacency in hit and miss production is obsolete. Oil production must and will approach the efficiency of other businesses, such as manufacturing. A manufacturer will not place an article on the market until he has fully investigated the processes involved, additional investment in equipment, costs of production, and expected profits. These may be modified by actual experience at a later date, but at least he begins with an idea of expected return. It is just as logical that an oil operator should investigate these same factors during the development and the early period of production of an oil reserve. The complexity of the problems existing in oil reservoirs should not be underestimated. Conversely, they should not be regarded as insoluble. Many completely defy solution, but there are others that can be solved completely or attacked intelligently to yield approximate results. The petroleum engineer has many tools, both figuratively and literally, at his disposal. Physical data such as core analyses, electrical logs, bottom-hole sample analyses, and bottom-hole pressures are accumulated extensively. Advances in the analytics of fluid flow have kept pace with the advances in measurement of physical data. It is the purpose of this paper to show how some of these records may be analyzed to define certain phases of reservoir behavior.

Jan 1, 1943

By Hubert Gamarra

El presente trabajo señala el proyecto de evaluación y recuperación del molibdeno en la mina Chabuca Sur, perteneciente a BHP Tintaya. El proyecto sigue la metodología de Excelencia operacional (EO) o metodología de mejora continua utilizada en BHP Tintaya S.A y se realiza a corto plazo, con la finalidad de incorporarla bajo un costo mínimo en el stock. Asimismo, se determina una asociación del S2Mo como un pulso tardío de mineralización sin cobre en la zona de alteración argílica de los diques monzoníticos y en el endoskarn.

Sep 13, 2001

By Mohammed Sakr

A Two-Section Helical Pile (TSHP) is a steel pipe with two shaft sections of different diameters and with one or more helix plates near the bottom of each shaft section. TSHPs are used regularly in western Canada as foundation pockets for single and double circuit distribution power line poles. The results of a comprehensive lateral pile load test program and the field monitoring of TSHPs installed in organic soil (muskeg) over soft clay are presented in this paper. A total of nine full scale lateral load tests were carried out, including seven tests using TSHPs with different diameters and embedment depths, and two tests using one-section helical piles. The prime objective of the study was to evaluate the lateral resistance of TSHPs installed into very soft organic soil (muskeg) overlying soft clay soils, to compare their lateral resistance relative to one-section helical piles and to compare the measured and the estimated lateral resistances using p-y curves. In order to provide sufficient soil data for analysis, the subsurface soil stratification was evaluated using two different techniques including; Cone Penetration Tests (CPT) and Portable Soil Probe Tests (PSPT). The two testing techniques were also compared and evaluated. This paper summarizes subsurface soil conditions, pile configuration, helical pile installation procedure, testing setup and results.

Jan 1, 2009

By Xiangjun Zuo

This paper firstly reviewed the state of the art in the recycling of used Printed Wiring Boards (PWB), and then presented part of the authors study on the combustion of PWB powders with and without the addition of catalyst. During the combustion of PWB powders without catalyst addition, there were two obvious exothermic reactions, one at 300-380oC, the other at 450-500oC. With the addition of catalyst during PWB combustion, there were no obvious exothermic reactions, indicating that dehalogenation reactions are not exothermic: The results showed that NaHCO3 and CaCO3 were very efficient to control the emission of Br2 and C6H6, lowering 80% compared to the case without catalyst, Na2CO3 can slightly control the emission of Br2 gas but not for C6H6 gas mission, and NaOH has no any effect of the control of both gases.

Jan 1, 2009