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By M. Connell, S. Bedrossian

Alkali cracking followed by chloride-based leaching is one of the prominent methods for rare earth element processing. Regeneration of the leach lixiviant, namely hydrochloric acid, is a critical operation in the process. A number of different process routes are available for recovery of hydrochloric acid from chloride solutions. The objective of this paper is to discuss various recovery routes and analyze the impact of several input variables on the variable operating cost.

Jan 1, 2014

By M. Maeda, H. Sasaki

Dissolution characteristics of metals vary significantly when they form alloys with other elements. Because hydrometallurgical processes are essential in separation and refining of non-ferrous metals, it is important to study behaviors of alloys in aqueous solutions. The authors have studied dissolution characteristics of precious metals in acid solutions using electrochemical measurement. When precious metals are alloyed with Zn, its dissolution is promoted by an increase in surface area caused by the preferential dissolution of this metal. The electrochemical study also revealed that precious metals dissolved from some alloys at unusually negative potentials; the underpotential dissolutions are explained by activations of these metals in the dealloying.

Jan 1, 2014

By A. Suzue, T. H. Okabe, Y. Taninouchi

Methods for the physical separation and enrichment of platinum group metals (PGMs) from autocatalyst scrap were studied in order to develop an environmentally friendly and efficient recycling process. In general, an autocatalyst has a honeycomb-structured ceramic substrate that is coated with a catalyst layer containing platinum (Pt), palladium (Pd), and rhodium (Rh). Therefore, physical separation of the PGM-containing catalyst layer directly from the ceramic substrate is favorable for upgrading the autocatalyst scrap. In this paper, the authors present a scrap-upgrade process consisting of electroless iron plating and magnetic separation techniques. Iron was plated on the surface of a catalyst sample used to represent an autocatalyst, which was then crushed and magnetically separated. The Pd in the catalyst sample was successfully extracted and concentrated in the magnetic powder. Under certain conditions, the process increased the Pd concentration by a factor of 4 and recovered 89% of the Pd in the autocatalyst sample.

Jan 1, 2014

By Lindsay A. Robertson

The long term management of acid generating tailings at mine closure is a common issue, however, management of ARD is significantly impacted by local conditions, including climate. Acid generating tailings, over time, will produce acid rock drainage (ARD) if left exposed to water and air, which both contribute to the sulphide oxidation process. The long term closure of tailings storage areas is a concern from both environmental and engineering perspectives, with long term acid generation and dam stability the main risks. Several approaches can be taken to minimize ARD from tailings facilities using cover systems. Three tailings facility cover case histories, in areas of net positive water balances, were investigated using unsaturated flow modelling software to determine the long term potential for limiting ARD by increasing saturation of the tailings and decreasing oxygen ingress. Each case study demonstrates the importance of integrating the tailings dam engineering into tailings cover closure design. Model predictions are compared to measured saturation levels to assess the accuracy of the calculations.

May 1, 2011

By M. Bertrand

Oxalic precipitation is usually applied to process radioactive wastes or to recover actinides from a multicomponent solution. Precipitation reactions being highly sensitive to many operation parameters, the computer simulation appears to be a very effective tool to forecast the evolutions of the system subjected to various operating conditions. This study focuses on the tetravalent uranium oxalate precipitation modelling which combines population balance and hydrodynamics. Both experimental and numerical studies are carried out in order to analyse the reactor design influence on the precipitate characteristics. The simulations taking into account primary nucleation and crystal growth are in agreement with experiments.

Aug 1, 2010

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

Weathered crust elution-deposited rare earth ore is a specific rare earth resource in China that is rich in middle and heavy rare earths. From surface to bottom, the weathered crust elution-deposit rare earth ores can be divided into humic layer, completely weathered layer, partly weathered layer, and bedrock. The exchangeable rare earth ions mainly exist in the completely weathered layer and partly weathered layer, and the exchangeable aluminum ions mainly exist in the humic layer. A novel solution injection method for use in the in-situ leaching technology of weathered crust elution-deposit rare earth ores was put forward based on the different distributions of RE3+ and Al3+ in the four layers. Avoiding the humic layer, only the completely weathered layer and partly weathered layer were leached by controlling the height of the leaching solution liquid level. In this way aluminum, the primary impurity in the RE leaching solution, can be decreased and the purity of the RE product can be improved. Meanwhile, the choices of available leaching reagents were broadened and the possibility of landslide disasters could be reduced.

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 Tom Shumka

INTRODUCTION ?This bull gear inspection technique was developed to provide more accurate data and faster inspection times than current techniques used today. ?Eddy Current Array (ECA) is a non-destructive testing technique that provides the ability to electronically drive multiple eddy current coils, which are placed side by side in the same probe assembly. Each individual eddy current coil in the probe produces a signal relative to the phase and amplitude of the structure below it. ?This data is referenced to an encoded position and time and represented graphically as a C-scan image. Most conventional eddy current flaw detection techniques can be reproduced with ECA inspections; however, the remarkable advantages of ECA technology allow improved inspection capabilities and significant time-savings.

Oct 1, 2010

By Marcel M. Djivre

The paper will outline the methods and test procedures including the evaluation criteria currently used at the Materials Testing Laboratory (MTL), Sudbury, Ontario, Canada, a laboratory approved by the Ontario Minister of Labour for the purpose of testing or examining mine shaft ropes or other hoisting appliances. Also for Canadian mines the paper will suggest proposed criteria to be used at MTL for the evaluation of ropes used in "ultra-deep" single-lift shafts. Most of the methods and test procedures currently used at MTL were adopted during the revision of the CSA Standard G4, Steel Wire Rope for General Purpose and for Mine Hoisting and Mine Haulage to be published most likely in year 2001. In this latest or sixth edition of CSA Standard G4, a new Clause 14 has been added outlining the requirements for in-service destructive testing of steel wire ropes for mine hoisting applications. The existing fifth edition of CSA Standard CAN/CSA -G4-92, which is intended for the manufacturing of new ropes, includes requirements for raw materials and construction features for round strand and flattened strand rope, and locked coil rope in bright and galvanized finish.

May 1, 2001

By Ajit K. Sinha

"Electromagnetic surveys were conducted over the Yava sandstone-hosted lead deposit in Nova Scotia to evaluate the usefulness of such surveys for detecting and mapping sedimentaryhosted metallic ore deposits. Both transient and multifrequency systems were used for that purpose. The deposit consists of three zones of disseminated galena which also contain minor amounts of pyrite and sphalerite filling the interstices of the sandstone grains. Each zone overlies a basement depression and is separated from the adjacent zone by an intervening basement high. A conductive shale layer underlies the galena-rich sandstone formation at all three zones.Because the concentration of galena (3070 to 4% ) and other sulfides is too low to affect the resistivity of the sandstone formations for detection by ground electromagnetic (EM) methods, the strategy for our survey was to look for areas of basement depressions and the presence of conductive shale in those depressions by EM depth soundings. The presence of the galena-rich sandstone formations could be inferred because of the close association of these two features with the deposits in the Yava area. Both transient and multifrequency EM systems were successful in mapping the basement depressions and detecting conductive shale at the three known mineralized zones. The technique, therefore, seems to offer good prospects for mapping similar stratabound sedimentary-hosted sulfide deposits."

Jan 1, 1993

By J. Gillies

"Extraction of Gold in Ketone from a suitably prepared sample of sulphide or siliceous ore or concentrate permits a rapid and accurate determination by Atomic Absorption. Mill test products and exploration development samples are acid-treated to effect complete dissolution of silver, copper, zinc, lead, molybdenum and iron present. Interferences in the determination of molybdenum are described. Results by Atomic Absorption are comparable to those afforded by other acceptable methods.INTRODUCTIONDuring recent years much has been written and discussed concerning Atomic Absorption Spectrometry as a technique for determining the concentration of metallic elements. We would, however, recommend a perusal of the paper presented by J. C. Ingles at the annual meeting of Canadian Gold Metallurgists held in Ottawa, January, 1966. The paper was published in the August, 1966, issue of the Canadian Mining Journal, and contains general information on Atomic Absorption.The purpose of our paper is to present certain specific method procedures for the determination of several precious and base metals normally present in Mine, Mill and Smelter products. Of necessity, analytical results should be as accurate as the most suitable available method permits, whether for metallurgical balance, settlement purpose, ore beneficiation programs, or exploration property development. The success of such programs is relative to the accuracy, speed and economics of the analysis. It is obvious, therefore, that in presenting our paper we consider the technique has achieved the desired evaluation."

Jan 1, 1968

By A. Tohn, K. Adham, R. Lu, D. Lemieux

"To remove sulphur, carbon and arsenic from the gold concentrates of Dundee Sustainable Technologies (DST), Hatch has designed a demonstration plant roaster using the fluid bed technology. The fluid bed was selected for its ability to maintain stable temperatures and uniform reaction conditions. Data points from a small pilot plant (operated by DST) were used for setting the parameters of the demo plant roaster.The DST demonstration plant is being built to further prove their patented gold extraction process at an industrial scale. Their gold extraction process is based on halogenation at atmospheric pressure and relatively low temperatures. Before the halogen leaching, most of the sulphur, carbon and arsenic should be roasted out of the feed concentrate.The Hatch fluid bed roaster design includes a moist feed introduction system, simple bed cooling for temperature control, and cyclone fines recirculation. The demonstration plant roaster is planned for construction in 2014, and the performance results will be presented in a future paper."

Jan 1, 2014

By Kadri Dagdelen

Recent trends of the mining project show that there will be more and more mechanized, largescale mining operations with complex process options to make low grade deposits economically feasible to develop. The global optimization of large scale, complex mine operations will become more important for the future mining. To serve the industry?s future needs, the OptiMine® software program is developed based on expertise gained at the Colorado School of Mines (CSM) for more than two decades, by using the special solution methodology based on the Mixed Integer Linear Programming (MILP) technique in the Operations Research (OR). The program has been beta-tested on more than 20 projects as a multi-time period scheduling and cutoff grade optimization tool that handles large scale open pit and underground mining operations involving complex process options, many stockpiles and dumps, blending requirements, and truck hour limitations. In each project, various operational options are evaluated in OptiMine® to develop strategic planning to help defining company?s strategies and directions. This paper demonstrates how the OptiMine® can be used to optimize a large scale, complex production scheduling problem on a case study coming from real world project. The case study describes multi-pit mine production scheduling optimization with pit backfills in such a fashion that acid generating waste rocks are encapsulated to minimize environmental impact.

Oct 1, 2009

By Michael K. Watkeys, Jacobus E. Potgieter, E. Guy Charlesworth, Carl R. Anhaeusser, Roger L. Gibson, Alexander F. M. Kisters

Intrusive features of cupriferous noritoids from the deeply eroded Proterozoic granite-gneiss terrane of the Okiep Copper District in South Africa illustrate the emplacement of basic magmas into a mid- to lower-erustal environment. The small, easterly trending intermediate to basic intrusions of the so-called Koperberg Suite display a wide variety of geometries, occurrence and emplacement modes, including dike-, sill- and plug-like bodies. Coeval granulite-facies metamorphism, partial melting and ductile deformation of country rock gneisses during intrusion of the basic magmas led to emplacement and dilation processes of the intrusions which differ significantly from those described for dikes and sills at shallow crustal levels. Regional tectonic stresses are largely negligible due to very low differential stress [( )] during deformation and intrusion, which permits emplacement at high angles to the principal compressive stress and which follows favorably inclined structural anisotropies. Dilation of the basic intrusions is largely determined by compositional differences of host rocks and occurs by thermal erosion, i.e., assimilation of wall rock gneisses. Low length-to-width ratios of basic to ultrabasic dikes and predominantly diapir-like outlines of mesocratic bodies are indicative of low viscosity contrasts between the mafic magmas and high-grade metamorphic host-rock gneisses. Buoyancy-controlled ascent of the basic to intermediate intrusions is expressed by a broad compositional zoning of basic bodies with respect to the granite-gneiss stratigraphy. Various intrusion modes within the stratigraphic column of the granite-gneiss sequence reflect a lithological and structural stratification of the seemingly homogeneous granite-gneiss terrane.

Jan 1, 1994

By P. D. P. Hamilton

IT is perhaps obvious to most individuals who are interested in the mining industry that a producing mine has been subjected to several phases of engineering attention. In this paper it is the author's hope that a thoughtful survey of these various engineering phases will emphasize certain points of value and interest which may sometimes be overlooked. The points which we will bring out are being made in an analytical sense and are not in any way a reflection on any individuals or organizations which might see in these illustrations a similarity co chair particular conditions. In other words, we are drawing on our general experience to illustrate the points which we chink are worthy of mention, and which we believe are of a type sufficiently frequent co be emphasized. It is well co point out chat, in this paper, we are not concerned with the relative importance of such theoretical questions as to whether or not a geologisc is more important than a prospector, or the office manager than the surface foreman. We are, however, interested in analyzing the various types of engineering experience required in the bringing of a mining enter-prise from the early prospect stage in co-production, and their importance to the project as a whole. In order to simplify our analysis of the subject, it has seemed best to outline a simple mining organization. In using the terms 'industry' and 'business', we feel chat frequently those engaged in mining do not always appreciate that mining is actually an endeavour, or a business, which has the same economic fundamentals as any other business. In the mining industry, the field and producing engineering are counter-parts of the research and production phases of any other type of business. Once this is realized, it is fairly obvious that mining, like any other industry, is a matter of economically acquiring raw materials, processing them, and finally marketing the resultant commodities as favourably as possible. The points may be discussed in a little more detail as follows.

Jan 1, 1938

By H. E. (Buzz) Neal

"Abstract - The Labrador Trough contains world-class iron deposits which have been mined since 1954. The direct shipping of Knob Lake ores were mined at Schefferville from 1954 to 1982. Concentrate production began in 1961 in the southwest end of the Trough, with three mines currently producing concentrate and pellets at a rate of 35 Mt per year. West and north of Schefferville, several billion tonnes of taconite have been outlined in fine-grained, cherty magnetite iron formation. Several deposits of highly metamorphosed magnetite-specularite iron formation are located west of Ungava Bay. Numerous studies have shown that this medium- to fine-grained iron formation can be beneficated to 66% to 68% iron. In the area from Wabush Lake to Mont-Wright, a medium- to coarse-grained friable specularite-quartz iron formation is repeated by folding to form several large deposits. In this area, three mining operations are located with reserves and resources in the order of 5 billion tonnes.The iron deposits occur within iron formation in sediments in the extensive Proterozoic geosyncline called the Labrador Trough. Several facies of iron formation within the Sokoman Formation reflect variations in chemical composition and depositional conditions. The correlation between the mineralogy and textures is discussed to illustrate the development of different types of iron ores. This band extends for about 1100 km southeast of Ungava Bay through both Quebec and Labrador. Further south, it turns southwest past the Wabush and Mont-Wright areas to within 300 km of the St. Lawrence River. The iron formation is essentially folded and faulted along most of its length. The degree of metamorphism is variable, ranging from intense in the northern and southern portions to greenschist facies in the central portion.The stratigraphy, structure and mineralogy of the producing mines are described along with the history of discoveries. Geological input is required to achieve the strict specifications of the international iron ore market."

Jan 1, 2000

By A. L. Williamson

Bio-mining is a cost-effective, energy efficient and potentially environmentally protective method of exploiting a variety of ore deposits, from high-grade base metal deposits of nickel to lower-grade uranium and rare earth deposits such as are found in the uraniferous quartz-pebble conglomerate beds of the Quirke Syncline, Elliot Lake, Ontario. The effectiveness of bio-mining in Elliot Lake depends on the success of bacterially-influenced dissolution of metals of economic importance. The determination of both the dissolution efficiency and rate controls for uranium and rare earth elements from bio-extraction processes is critical to assess the potential for success of bio-mining along the Quirke Syncline. This poster provides an overview of proton-mediated biogeochemical dissolution of more than 50 elements, including uranium and rare earth elements from samples of the low grade uraniferous ore collected as drill core from the Elliot Lake area. The elemental data is quantified using advanced spectroscopic tools (ICP-MS and ICP-AES) to analyze solutions obtained from a series of environmentally controlled biologically-mediated uranium ore extraction experiments. The findings are being to guide design of larger scale bio-leaching experiments to further assess the potential for success of bio-mining along the Quirke Syncline.

Aug 1, 2010

By J. Brent Hiskey

At present, approximately 80 % of the worlds mine production of copper is achieved by smelting and electrorefining. The principle aim of copper electrorefining is to satisfy the large demand for extremely pure copper. It is remarkable that high quality copper cathodes with the required purity (99.99+% Cu, ASTM B115-10) and structural characteristics (i.e. deposit density and morphological texture) are produced from impure copper anodes dissolved in electrolytes containing a variety of impurities. This is accomplished with the proper control of operating parameters such as: current density; temperature; copper and sulfuric acid concentration; agitation; substrate preparation; and the application of electrolyte additives. The basic elements of the electrolysis of copper have not changed significantly over the past 150 years since the early developments of James Elkington. Importantly, our fundamental understanding of the underlying electrochemistry has advanced considerably. This is especially true regarding our knowledge of the mechanistic role of additives during the electrocrystallization of copper. This is a very complex subject and modern electrochemical techniques and the development of surface characterization and imaging instruments has helped immensely in our ultimate understanding of how additives control the deposit structure and morphology. The purpose of this paper is to review the historical development and application of electrolyte additives in copper electrorefining and to examine our current knowledge regarding their use. INTRODUCTION The first transatlantic telegraph cable was completed in August 1858. Regrettably, this cable failed shortly after the initial connections. After several more failed attempts, improvements in materials and copper quality resulted in successful communication between Europe and America on July 28, 1866. In many ways this hallmark event demonstrated the need for high purity copper. The first copper refinery in the world was commissioned in May 1869 in Pembrey, South Wales by partners Josiah Mason and James Balleney Elkington. (Historical Note). The 1865 and 1868 British patents issued to James Balleney Elkington were the foundation for the first commercial production of high purity electrolytic copper (Elkington, 1865, 1869, 1870). This important achievement was made possible primarily by the invention of the dynamo which was based on the fundamental operating principles advanced by Michael Faraday. A symbiotic relationship between copper refining and the dynamo was henceforth established. The dynamo provided electric current for electrolytic refining of copper and the electrorefining tankhouse provided pure copper which was required for the generation and transmission of electricity.

Jan 1, 2019

By J. Kuipers, R. W. Lawrence, P. B. Marchant, W. Brooks, J. T. Chapman

"Bioleach testing and piloting was conducted on refractory gold sulphide concentrate from Austin Gold Venture in Nevada during 1988. The objective of the test programme was to determine the technical and commercial viability of bioleaching as a concentrate pretreatment step prior to gold extraction by cyanidation. Baseline CIL cyanidation typically resulted in < 20% gold extraction from the Austin concentrate. Bioleaching enhanced gold extraction up to 95% using conventional CIL techniques. This paper summarizes the bioleach test programme and results, including pilot plant studies onsite, and describes the commercial design details for a possible retrofit of the Austin flotation tailings leach circuit to accommodate 20 tpd and 40 tpd capacity concentrate bioleach facilities.INTRODUCTIONBioleach testing on a refractory carbonaceous sulphide concentrate from Austin Gold Venture (AGV), was initiated in late 1987 as part of an ongoing programme at Austin to investigate alternatives to concentrate smelting. Preliminary batch biooxidation tests at Coastech indicated that over 90% gold extraction by carbon-in-leach (CIL) cyanidation of the bioleach residue could be achieved, compared with less than 20% gold extraction on untreated concentrate by similar CIL processing.Subsequently, a more rigorous laboratory study was undertaken at Coastech to establish continuous biooxidation operating criteria on a bench scale. The objective of continuous testing in the laboratory was to provide confirmation of enhanced CIL response based on continuous bioleach products and to determine key process operating and design parameters for pilot testing. The success of the laboratory test program led to the installation of a mobile pilot plant at Austin Gold Venture. The plant was operated by Coastech and AGV during 1988 to provide scaleup data and design criteria for commercial design and feasibility analysis. Based on pilot plant operating data, a detailed commercial bioleach plant was designed as a possible retrofit to the existing 1000 tpd CIL plant. Capital and operating costs were estimated to provide a commercial feasibility study of bioleaching as an oxidative pretreatment for Austin refractory concentrate."

Jan 1, 1989

By A. L. Williamson

Bio-mining, the use of micro-organisms to recover elements of interest, is potentially useful for the economic extraction and recovery of ore metals from a variety of ore deposits, including the lowergrade uranium deposits found in the uraniferous quartz-pebble conglomerate beds of the Quirke Syncline, Elliot Lake, Ontario. The metabolism of chemolithotropic bacterium Acidithiobacillus ferrooxidans depends on an ability to derive energy and reducing power from the oxidation of ferrous iron found in a varirty of iron sulphide minerals associated with base, precious metal and uraniferous ores. The characteristics of this bacterium, especially the ability to oxidize both iron and sulphur with an associated high tolerance of low acidity, allow the organism to contribute significantly to bio-mining processes. Under ideal conditions, A. ferrooxidans promotes the oxidation of ferrous iron in low sulphide ore materials, breaking the crystal structure of the ore minerals .releasing protons to the surrounding solutions, thus promoting the dissolution of uranium and rare earth elements, among others. This paper provides an overview of elemental dissolution and release of uranium, rare earth elements and investigates the acid generating potential of the final residues, from a series of environmentally controlled, biologically-mediated uranium ore extraction experiments. The findings will be used to guide in the design of larger scale bio-leaching experiments to further assess the potential for successful bio-mining operations along the Quirke Syncline.

Aug 1, 2010