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By Y. Y. Yemelyanov, S. S. Gudkov, A. V. Boldyrev, A. V. Bogorodskiy, S. V. Balikov

"A series of tests to optimize pressure oxidation- carbon-in-leach process (POX-CIL) of goldbearing flotation concentrate with the addition of sodium chloride and activated carbon were carried out. Flotation concentrate which was generated during primary ores concentration from a large Russian deposit was used for these tests. The tests were performed with different concentrations of sodium chloride. It was found that the required sodium chloride concentration for gold leaching was 5 g/L. The tests performed with different additions of activated carbon showed that the amount of activated carbon should be at least 6% of the concentrate mass. The rate of sulfides oxidation was 67.7–99.8 %. The highest gold recovery was 98.6 %.INTRODUCTIONThe majority of gold-bearing ores are recommended to classify as amenable to cyanidation and refractory. Processes at elevated pressures and temperatures have become increasingly important in base metals hydrometallurgy (Lodeischikov, 1999, 2007; Naboichenko, Shneerson, Kalashnikova, & Chugaev, 2009; Thomas, 2005).Current pressure autoclaves – cyanidation flow sheets are capital intensive due to numerous circuits and the use of environmentally-unfriendly sodium cyanide. The use of halide-based lixiviants during pressure oxidation of precious metals can be a promising technique for refractory sulfide goldbearing mineral raw material hydrometallurgical processing (Fleming, 2002, 2007, Kotlyar, Meretukov, & Strizhko, 2005).In this paper, we presented the results of the research on finding the optimum process parameters of pressure oxidation using an adsorbent for a refractory gold-bearing concentrate. A proposed flow sheet involves (Bogorodsky, Yelelianov, & Balikov, 2012):1. Gold-bearing sulfides oxidation followed by precious metals dissolution and the formation of gold and silver chloride complex;2. Reaction of the precious metals chloride complex with a carbon-based adsorbent;3. Precipitation of precious metals onto the adsorbent by EW and smelting of cathode precipitates into Dore bullions.This process allows POX of gold-bearing sulfides, precious metals dissolution and their precipitation on the adsorbent to be executed in one single vessel. This study found that the most suitable lixiviant was sodium chloride. Fleming (2002) suggested that in the presence of a halide-based reagent (e.g. chlorine- ion reaction), the dissolution of gold during POX is achieved according to reaction 1:"

Jan 1, 2016

By R. D. Brown

Higher employer costs and increased employee benefits will result from the current sweeping revisions of the un-employment insurance system now receiving consideration before Parliament. The new legislation, the Un-employment Insurance Act, 1971, will substantially increase the unemployment insurance costs of many employers through an increase in the level of employer contributions -generally, employer contributions will go to 1.4 times employee costs -as well as by extending coverage to many classes of employees now exempt. Under the new legislation, executives, technicians, teachers, institutional workers and others will be covered, and eligible for the higher benefits which it provides. For the first time, absence from work because of illness or accident may qualify individuals for unemployment insurance benefits.

Jan 1, 1971

By S. K. Dimitrov

?Ellatzite Med? is one of the biggest mining companies in Bulgaria, processing about 12,000,000 t of ore per year. Waste materials left after extraction of copper concentrate are deposited in tailings dam ?Benkovski 2?. The hydraulic structure is built according to the downstream method, through hydrocyclonization where the downstream batter and the body of the wall are formed by the separated coarse sand particles of the separated tailings. In connection with the prolonged concession of Ellatzite Med and the enlarged capacity of Benkovski 2, the tailings dam has expanded on to the surrounding terrain. To guarantee a normal hydrocyclonization and build up of a tailings wall during waste deposition from the ore mill, the technological scheme of the hydraulic transport system of Benkovski 2 has been changed.

Aug 1, 2013

By T. K. Bose

According to the Intergovernmental Panel on Climate Change (IPCC), the average global temperature has risen over the last century. If this trend continues over the next century, the IPCC projects a significant increase in temperature and a rise in sea level. The changes in climate could adversely impact human health, agriculture, water resources and ecosystems. Most national and international agencies have concluded that our use of carbon-rich fuel is responsible for global warming through the greenhouse effect. In the future, the situation may get worse if the increased need for energy in countries like China, India and Brazil is fulfilled by burning fossil fuel. Advanced natural gas-fuelled vehicles have the potential to reduce carbon monoxide and reactive hydrocarbon emissions substantially compared to gasoline vehicles. Further environmental benefits can be realized by using a blend of natural gas and hydrogen. Such an approach will help create an infrastructure for an eventual transition to hydrogen.

Jan 1, 2005

By C. R. Tang

The respirable dust real-time monitoring equipment export information is complex, and electromagnetic wave wireless transmission is affected largely under mine conditions. The respirable dust concentration information transmission method based on led light equipment is proposed. The respirable dust concentration data of the individual real-time monitoring equipment is encoded to fit the system transmission; the encoded signal is modulated onto the LED mine lamp; the light signal is transmitted by the spatial channel; the signal is received by the receiver to the photoelectric conversion to restore the respirable dust concentration data for subsequent processing. Simulation and verification experiments showed that the respirable dust concentration information transmission method based on led light equipment can achieve the LED miners? lamps visible light wireless data transmission.

Aug 1, 2013

By E. N. Gilje

"IntroductionDURING the past five years, over two miles of shaft sinking have been completed at Falconbridge. As sinking has continued, we have improved our equipment and technique with a resulting increase in efficiency. Throughout this period, all sinking has been done by contracting firms, under our direction and to our equipment specifications, with highly satisfactory results. Since 1949, Riddell shaft mucking machines have been successfully used in conjunction with the •benching method of sinking. Our most recent practice can best be illustrated by describing the method used in sinking No. 1 shaft at the Fecunis Lake mine.No. 1 Shaft, Fecunis Lake MineNo. 1 shaft, consisting of six compartments and measuring 13 ft. 11 l/2 in. by 19 ft. 9 3/8 in., outside timber (Figure 1), will be sunk to a depth of 4,170 feet. It was designed to accommodate two 10-ft.diam. Koepe hoists."

Jan 1, 1955

By D. Furrer, M. Dallaire

The arrival of Image analysis in the last 20 years has changed the world of quantitative metallography. Many standard measurement techniques which were previously manual can now be done with fully automated systems. This reduces subjectivity and operator fatigue and therefore enhances the quality of the statistical results. In many laboratories, Titanium Alloy microstructures continue to be evaluated by traditional methods, where quality of results is subject to operator fatigue and level of experience. Advances in Camera technology have tremendously improved image acquisition. One can often see clearly at 500x what can not be observed at 1000x, allowing for a larger area to be analyzed, without the inconveniences associated with very high magnification objectives. Powerful and versatile Image analysis software combined with a high precision motorized stage gives access to a multitude of applications, which were extremely challenging or impossible until now. Image Analysis tools such as Multilayer Grab, which reconstructs an uneven image into one plane of focus (ex. Observation at high magnification of texture resulting from etching) and Mosaic which builds an image from a number of fields of view (ex. Reconstruction of very large grains at low magnifications) expand even further the power and flexibility of IA systems. This presentation will describe how automated methods are applied to the point count method and grain size measurement. We will show how cameras and software work together to permit quantitative measurements of primary alpha and prior beta microstructures, as well as lamellar alpha plate thickness in titanium alloys.Automated and semi automated quantitative measurements of various Titanium microstrures have been assessed, using the Clemex Vision PE. Examples of the methods and steps used are presented.

Jan 1, 2006

Experimental determination of the response of an AG/SAG mill treating two components of significantly different impact resistance is challenging for two main reasons: firstly, small scale laboratory tests have yet to be confirmed as valid representations of the full scale milling environment, and secondly pilot plant testing requires 10-20 tonnes of ore per scenario which precludes the use of drill core, rendering the process very expensive. In order to mitigate these difficulties, modelling was considered as a potential way forward. However, as the JKSimMet AG/SAG model currently has no capacity to simulate the interaction of two ore types with differing impact resistance, density and/or feed size distributions, an alternative modelling approach was developed. This approach aims to essentially calibrate the AG/SAG process under a set of given conditions, for which survey data and the ore properties of the main components in the feed blend already exist. This paper describes a new conceptual model, which provides a simplified approach for investigating the multi-component behaviour of two ores of differing hardness/SG in a given AG/SAG milling environment, and which can potentially be used for scale-up from laboratory/pilot testwork and geometallurgical estimation of throughput.

Jan 1, 2012

By Xiu-Xiang Tao

This study investigated bio-liquefaction of lignite and its model compounds of thymol, bezioc acid and quinoline by a fungus, Hypocrea lixii AH. It analyzed, during bio-liquefaction, enzyme activity of oxidase, LiP, Lac, MnP and polyphenol oxidase, and degradation products by UV-Vis, FTIR, 13C NMR and GC-MS. The results showed that the bio-liquefaction percentage (by mass) of lignite was up to 44.86 %. The bio-liquefaction products of lignite were mainly aniline, amide, ether, carboxylic acid ketone and ester. The aromatic ring number was 1-3 with an aromatic carbon ratio of 0.328, which indicated rings opening, bonds breaking and oxidation reaction. By considering with the enzyme activity analysis results, it showed that LiP and Lac catalyzed reactions to open aromatic cycles and to break bonds; esterase to break ester bond; and peroxidase in oxidation reaction.

Aug 1, 2013

By D. H. Flather, J. W. Hendry, K. Drover

Black Hawk Mining Inc. has completed a comprehensive program on the prediction and management of acid rock drainage (ARD) at their Keystone Gold Mine (Keystone) near Lynn Lake, Manitoba. The program, initiated in 1994, followed a phased approach utilizing initial acid-base accounting (ABA) results and subsequent laboratory kinetic testwork to define site-specific sulphide oxidation and neutralization consumption rates in waste rock. Net acid generating waste rock at Keystone was defined through the kinetic testwork as waste rock yielding a net potential ratio (NPR) of less than two. A preliminary waste rock management program based on blending of potentially acid generating and acid neutralizing waste rock was advanced. Subsequent refinement of the management program followed the analysis of over 1580 ABA samples collected from individual blast holes during the initial bench development phase of the Keystone pit. Uncertainties in actually achieving adequate blending within the dumps at a mining- scale resulted in the development of a revised waste rock management program based on segregation. Recognizing that any successful management plan requires that the ARD characteristics of the waste rock be identified prior to in-pit blasting, the extensive ABA database was utilized to develop a rapid characterization scheme. By implementing a characterization scheme based on total sulphur concentrations and fizz rating, waste rock could be quickly segregated without delaying the natural flow of ore from the pit. Interestingly, it also became apparent that gold values were strongly correlated with total sulphur, such that traditional fire assays were supplanted with a simple and more cost-effective total sulphur determination. The program highlights the importance and benefits of collecting and exploiting data beyond that necessary to acquire appropriate development permits.

Jan 1, 2000

By T. M. Ruff

A GPS-based traffic awareness and collision avoidance system has been implemented at mines with long, narrow access roads to help avoid accidents involving two approaching vehicles or vehicles following too close. A simple display in the cab of each outfitted vehicle gives an indication of oncoming traffic and a voice announcement indicates the type of vehicle that is coming as far out as 300 meters. Advanced warning of approaching vehicles is increasing driver awareness, especially around blind corners and in adverse weather such as heavy fog, snow, or rain. Speeding alarms have also been implemented and are especially critical as a vehicle approaches reduced speed areas near single-lane bridges or tight curves. A description of the system, safety improvements seen since its introduction, and implementation challenges will be discussed.

Aug 1, 2013

By E. A. Roux

As the first mine-to-metal zinc operation utilising atmospheric leaching, solvent extraction and electrowinning, Skorpion Zinc faces unique challenges and opportunities. One of these challenges is found in the solvent extraction circuit, in which di-ethylhexyl phosphoric acid (D2EHPA) is used as the organic extractant. Although D2EHPA is an excellent extractant for zinc, it suffers from the co-extraction of ferric iron, which is produced during leaching and by the corrosion of the grinding media. This situation is partially mitigated by iron precipitation in the neutralisation step prior to solvent extraction. Unfortunately, some ferric iron still reports to the solvent extraction process. This leads to a slow build up of iron in the organic phase. Chemical stripping is used to maintain the Fe concentration at an acceptable level. In this paper, the efficiency of the iron removal process is discussed.

Jan 1, 2006

By M. B. Mansur, A. S. Guimarães, A. J. M. Santanilla, D. C. R. Espinosa, J. A. S. Tenório, R. A. Pini

The separation of Ni and Co from sulphate medium containing Mn, Mg, Cu and Ca was carried out by solvent extraction. The object of this study was to investigate the synergistic effect using phosphinic acid (Cyanex 272) and carboxylic acid (Versatic 10) and their mixtures in kerosene. The extraction percent of each metal ion was found to increase with increasing pH and extractant concentration. Co was preferentially extracted over Ni under the same extraction conditions. The separation factors of Ni/Co increased with the use of the synergistic systems investigated.

Jan 1, 2014

By Chris Twigge-Molecey

Demand for metals will continue to grow as global population numbers and prosperity levels steadily increase. Consequently, there will continue to be a need to design and construct new metallurgical plants. Business success in general requires projects to be financially successful and return appropriate value to their owners. However, in the metals industry, private and public sector financing sources have become very sensitive to the perceived inability of projects to contain costs and meet other business objectives. Thus, the capital for projects has become more difficult and expensive to obtain. It is instructive to note that Ernst and Young (2011) identified that: “Delivery of predictable project results bestows competitive advantage and market confidence to those corporations who successfully instill this discipline”. The implication for future projects is that they must be systematically developed to minimize perceived risks—and more importantly—to demonstrate that the risks are managed to achieve the business case. Then, provided that the project has been developed in a well-structured way, project success can again be defined as a project with: a final cost within 10% of the budget approved at the end of FEL3, when the project is properly defined and the permit conditions are agreed upon; a start-up date within three months of the definitive, scheduled startup date; production levels at 85% of design capacity within a year of starting commercial operation; production meeting the target environmental restrictions; and with zero lost time accidents during construction and startup. The plant design is one of many integrated activities required to achieve these objectives. This book represents a valuable link between the existing engineering literature that encompasses a wide range of engineering fundamental textbooks and design manuals and the project management literature such as the Project Management Body of Knowledge, or PMBOK® (Project Management Institute, 2014). It is evident throughout this book, that the design team is a small but essential part of a much larger project team comprising the project management, construction management, and construction contractor staff. Design activities must be regarded and managed as part of the integrated whole, with two fundamental links throughout the design process:

Jan 1, 2015

By G. J. Arseneau

Mineral resource statements are reported as tonnage and grades. While great care is placed on generating a reliable estimation of grade, the determination of bulk density for resource estimation is often overlooked. Often mineral resource statements are prepared using a simple average value of bulk density. While a simple average estimate of bulk density can be appropriate for some deposit types, an over simplistic estimation of bulk density can result in serious errors in tonnage estimates and consequently to an over or under estimation of metal content. The construction of a reliable bulk density model requires an adequate bulk density database in order to develop a good understanding of the variability of bulk density with grade and geology. A reliable bulk density database is also essential in determining the appropriate modeling technique to minimize the errors in mineral resource statements caused by incorrect bulk density determinations. This paper summarizes bulk density measuring techniques and draws on examples from various deposit types examining the basic principles of bulk density modeling and domain construction for each deposit type. Examples are presented of simple bulk density domains and more complex grade variable bulk density domains with a discussion of best approaches for minimizing errors in density estimation.

Aug 1, 2013

By M. Dupuis, V. Bojarevics

It is well known that horizontal current density in the metal pad contributes greatly to the generation of MHD driven bath-metal interface wave. It is possible to compute very accurately the metal pad current density using a very detailed finite element model [1], but a MHD model must be compatible to this level of mesh refinement and to recalculate the current distribution at each time step, including the full busbar supply system. The accuracy of the instability prediction of the cell depends on the accuracy of the metal pad current density calculation. This study presents the comparison of the metal pad current density calculation of the detailed finite element model and the MHD-Valdis model for different metal pad heights and ledge thickness. It also presents the corresponding cell MHD stability predictions.

Jan 1, 2006

By M. Greyling, C. Panaou, M. Bellino

Commonly the most frequent method of calculating the overall mass balance of a multi mineral platinum-group metal (PGM) concentrator circuit in Southern Africa has been through the use of spreadsheets, typically Microsoft EXCEL®. While there are some advantages in using spreadsheet based mass balances during the conceptual design phase of the project, their use becomes limited in the detailed design phase of the project. This paper discusses the successful application of METSIM® for mass balancing of a PGM concentrator and highlights the benefits gained during the conceptual and design phase of the project.

Jan 1, 2005

By Claudio Rocha Rosales

"Peñoles is a mining group with integrated operations in the smelting and refining of non-ferrous metals, and is also a chemicals producer. Peñoles is the world’s foremost producer of refined silver, metallic bismuth and sodium sulphate and is the leading Latin American producer of refined gold, lead and zinc. The Met-Mex Peñoles Zinc Plant commenced operations in 1973 with an annual production capacity of 105,000 t/y. Year after year the production has been increased, and at present, the production capacity is 240,000 t/y. In this paper, the leaching process,particularly the operation of the jarosite circuit is reviewed ,specifying process improvements to treat high iron calcines.INTRODUCTIONThe purpose of the leaching process is to recover the metals, mainly zinc,through a series of extraction stages with sulphuric acid solutions, which progressively increase the zinc recovery. After the series of acidification stages,the solution, which is rich in iron, is sent to the jarosite circuit to separate the zinc from the iron (Garcia & Valdez, 1996).The first step of the leaching process is the neutral leach circuit which produces a zinc sulphate solution that is sent to the purification section for the removal of impurities such as cadmium, cobalt and copper, after this solution is sent to the tankhouse to feed the electrolytic cells."

Jan 1, 2016

By J. E. Hawley

"The zinc-lead deposit of the Lake Geneva Mining Company is on lot 7, con. VI, Hess township, Sudbury district, Ontario, about 10 miles northwest of the northern rim of the Sudbury Basin. Though a relatively small deposit, it shows some rather interesting relations to cross-cutting, pre-ore, quartz diabase dykes, which merit description.The deposit was discovered in October 1924 by J. H. Collins beneath iron-stained drift and oxidized sulphides. This proved to be the northwestern extremity of the orebody, the remainder of which extends southeast below swampy ground. Exploration began in 1927. In 1928 a vertical shaft was sunk to 250 feet and a level established at 235 feet. Later the shaft was deepened to 400 feet and new levels opened at 315 and 375 feet. In 1943 an inclined winze was sunk below the vein from the 315-foot level to a vertical depth of 640 feet, and two additional levels were opened at 525 and 615 feet respectively.The geology of the area has been described by T. T. Quirke (1), F. F. Osborne (2), F. J. Alcock (3), and Ralph Tuck (4). Private reports have also been made by Carl Tolman, J. E. Gill, and K. W. Fritzsche. Tuck's paper, covering the work completed to 1930, gives a detailed account of the character of the ore and enclosing rocks.Up to May 1944, when the property was closed, all ore above the 375-foot level and a small tonnage from below this elevation had been removed. Ore mined from 1941 to 1944 yielded the following:"

Jan 1, 1954

By J. Costigan, C. Corless

In 1997, damage as a result of Castrol R40 entering the INCO pressure carbonyl plant carrier gas stream was becoming increasingly severe. The oil in the gas stream was adversely affecting both equipment availability and process control resulting in rising unit costs. The main source of the Castrol R40 was determined to be the carrier gas and low pressure gas blowers. Plant personnel initiated a plan to prevent the Castrol R40 from entering the carrier gas stream by replacing the mechanical shaft seals with Ferrofluidics seals on these blowers. The following paper details a brief case history of the Castrol R40 in the carrier gas including impact on the plant. This will be followed by a technical discussion of the new sealing arrangement that was developed by plant personnel, Roots Blower and Ferrofluidics. Lastly, this paper will update the status of the blower upgrade project and document the results to date.

Jan 1, 2000