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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). Part III reviewed the large-scale demonstration of the MT-DEW-SX process at Bagdad, Arizona. Key features of the process were the use of superfine grinding of the concentrate (to a P98 of 12 to 15 µm and a P80 of 6 to 7 µm), pressure leaching at 160ºC with 1,380 kPa (200 psig) oxygen overpressure, DEW to produce LME Grade A cathode, recycling some of the lean electrolyte to the pressure leaching step, and treatment of a lean electrolyte bleed by solution extraction (SX). Recycling of 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 for pressure leaching. This paper (Part IV) discusses the development and design of a full-scale commercial application for the Morenci operation in Arizona.

Jan 1, 2007

By Lorena Cristina Amorim Moura

As coquerias enfrentam um grande problema que é a oxidação do carvão. Este fenômeno as afeta diretamente, pois deterioram as propriedades coqueificante do material, impactando na síntese do coque metalúrgico. Portanto, gerando perda de valor econômico, uma vez que as propriedades coqueificantes são fatores que determinam a atratividade e o custo do carvão. Sendo assim, torna-se necessário o uso de medidas para retardar o efeito da oxidação, garantindo a menor perda possível, desde a extração do carvão mineral da mina, até o carregamento nos fornos de coqueificação. Neste estudo em particular, definiu-se uma equação para previsão do decaimento de fluidez, que é a principal propriedade afetada pela oxidação, e matéria volátil de carvões em pilhas a céu aberto. Foi também desenvolvido o estudo do efeito da aspersão de uma camada polimérica para minimizar os decaimentos de fluidez e matéria volátil.

Oct 30, 2017

By Wayne Phillips, Anatalia Silva, Robert Henderson, Tondo. Luis

"Kinross’ Paracatu Mine has 20 years of operational success as one of the lowest grade milloperated gold mines in the world. At year end 2005, Paracatu’s Proven and Probable Reserves were 1.18 billion tonnes at a grade of 0.40 g/t Au, containing a total of 15.2 million ounces of gold.In 2005, the plant processed 17 Mt of ore and produced 180,519 ounces of gold at a cash cost of US$274/oz. An investment of US$470 million has been approved to expand production to 61 Mtpa in 2009 which will extend mine life to 2036. During the period from 2009 to 2013 the project is expected to produce an average annual output of approximately 557,000 ounces of gold at an average cost of sales of approximately $230 per ounce.The soft, friable ore containing readily leachable gold associated with sulphides lends itself to simple processing. The process flowsheet consists of crushing, grinding, gravity recovery, flotation, concentrate leach and carbon adsorption to produce bullion bars. This paper describes the current operation, the deposit’s unique metallurgical features and the future expansion plant that has been designed to optimise recovery of gold.INTRODUCTIONRio Paracatu Mineração (RPM), a wholly owned subsidiary of Kinross Gold Corporation, operates the Paracatu mine. The mine is located in Brazil, 230 km south west of Brasilia in the north west portion of the State of Minas Gerais. The city of Paracatu, which has a population of 83,000 people, is just 2 km south of the mine."

Jan 1, 2007

By M. Gaumont, F. Robichaud

"Agnico Eagle Mines Limited (AEM) is a Canadian-based gold producer with operations in Canada, Finland and Mexico. In 2010, AEM produced its first gold bar in Nunavut, Canada as it started its Meadowbank operation. It is also in 2010 that AEM acquired the Meliadine property, which is located 25 Km North of Rankin Inlet, Nunavut, Canada. The Meliadine gold project is an advanced exploration and development project, comprising of workers camp, underground and open mines, a processing plant and all the services facilities and infrastructures required to sustain operation in a remote arctic environment.Pending formal board approval, production start-up is planned for Q3 2019 and the process flowsheet is based on an ore processing rate of 1.1 million dry tonnes per year (3,000 dry tonnes per day from underground mining) for the first three years, and 1.98 million dry tonnes per year (5,000 dry tonnes per day from both underground and open pit mining) for the remaining years at 92% process plant availability.To the end of 2015, more than 45 metallurgical test programs have been conducted on the Meliadine deposits. Based on the results of these programs, an optimal gold circuit was designed, comprising of crushing, grinding, gravity separation and cyanide leaching with a carbon-in-leach circuit (CIL), followed by cyanide destruction and filtration of the tails for dry stacking. The assumed gold recovery for the reserves averages 96.0% at a 7.44-g/t gold average mill feed grade."

Jan 1, 2016

By D. Bois, P. Keating, J. Lemieux, M. A. Vallée, M. Allard, R. S. Smith, L. Z. Cheng, M. Chouteau, D. K. Fountain

"As part of a larger research program, a number of MEGATEM airborne electromagnetic (EM) test flights were flown over the Gallen massive sulfide deposit in northwest Québec. A particularity of this test site is that a major part of the ore body was extracted before the MEGATEM survey. Therefore one of the purposes of this study was to verify the ability of the system to detect the remaining massive sulfides below the water in the open pit. The open pit is also surrounded by a metallic fence, and a power line is present in the vicinity. A large part of the case study involved accounting for the impact of infrastructure and acidic water on the survey, which will help in the interpretation of airborne EM responses in complex exploration situations.The Gallen deposit was also previously flown with the INPUT and GEOTEM airborne EM systems before the major exploitation period. A comparison between the results from the different survey results allows estimation of the physical properties of the Gallen deposit, which is a relatively poor conductor.A new method for removing the power line signal shows amplitudes with a smaller residual associated with the emanating fields, and more compact, cleaner responses associated with induced currents. This will make it easier to identify bedrock conductors close to power lines"

Jan 1, 2007

By Klaus Stoss, Bernd Braun

The sinking and lining of a large mine shaft with 8.0 m i.d. and 1,133 m total depth is described in detail. The ground freezing method was applied to safely sink the shaft through unstable, waterbearing strata. Following a brief introduction to the geological and hydrological conditions and the owner's shaft requirements, is the general technical concept to sink and line the shaft. Particular emphasis is put on the lining system which has to provide stability and absolute watertightness for the lifetime of the shaft, even though mining takes place in its immediate proximity. Machinery and equipment used to execute the work are mentioned and commented. Furthermore, the excavation and lining of the large filling stations using rock anchors and shotcrete are described. Details on performance rates are given.

Jan 1, 1983

By J. L. Ellenberger, G. S. Esterhuizen, T. Miller, M. M. Murphy

A limestone mine in Ohio has had roof instability problems that have led to massive roof falls extending to the surface. This paper describes a collaborative study of these events undertaken by the National Institute for Occupational Safety and Health and the mine owners. The study focuses on the roles that weak, moisture-sensitive floor and weak bands in pillars play in a general instability that led to roof falls at this mine. The NIOSH Stone Mine Pillar Design software (S-Pillar) does not include analysis for weak floor or weak bands and recommends that when such issues arise they should be investigated further using a more advanced analysis. It is important to recognize that without the impact of the floor or weak bands, the calculated inherent stability factor for these pillars is within the recommended design range. Therefore, to further investigate the observed instability occurring on a large scale at the Ohio mine, FLAC3D numerical models were employed to help determine the failure mechanism. Roof-to-floor convergence monitors were also installed in the areas predicted to have further instability. This case study will provide important information to limestone mine operators regarding the impact of weak floor causing the potential for roof collapse, pillar failure, and subsequent subsidence of the ground surface. This recent case demonstrates that weak floor can be a significant factor in pillar stability and should be assessed during the design stage of the mine.

Jan 1, 2015

By E. O. T. Simpson

"IntroductionAS COMPARED with coal mines in the United States, and even with some of those in eastern Canada, the coal mines of western Canada, generally speaking, :have made little progress toward mechanization at the working faces. So far as Vancouver island is concerned, there are three main reasons for this : ( 1 ) in some areas, conditions• easy for hand-loading but unsuitable for mechanical loading make high outputs per man •possible by the former method; (2) faulting of the coal seams in ..some areas precludes long-term planning and the introduction and efficient use of expensive equipment; (3) thinness •and other characteristics of the seams in many areas favour hand-loading.No. 8 MINENo. 8 mine of Canadian Collieries (Dunsmuir), Limited, is located in the Cumberland sub-area of the Comox coalfield on Vancouver island about 90 miles west-northwest of Vancouver. The geological structure of this coalfield has been described by J. D. McKenzie. The seams occur in the Comox formation, a subdivision of the Upper Cretaceous Nanaimo Group. The formation is of near-shore origin and was laid down on an irregular surface of' older rocks. The irregular generally have a northeasterly dip, modified by gentile folds and by a •few large, and a number of smaller, faults.Four seams have been worked in the Cumberland area and all vary in thickness and in the amount and number of interstratified bone and rock •bands."

Jan 1, 1953

By L. du Plessis

The name FISH (Fully Integrated Sort House) refers to a class of technology deployed at Jwaneng Mine final diamond recovery. The FISH concept is based on three pillars, namely: ?Improved sorting efficiency FISH is based on laser technology, which is more efficient than hand sorting for certain product categories. Laser sorting is based on measuring in-elastically scattered light from molecules and this is referred to as Raman spectroscopy. The Raman scattered light occurs at wavelengths that are shifted from the incident light by the energies of molecular vibrations ?Availability of production information Roller gap diamond size distribution information is generated on line for upstream process optimization ?Improved product security A ?hands-off? philosophy reduces security risk during operation and maintenance of the plant. In addition, a number of lessons were learnt about the application of new technologies in the industry: ?The required human competency profile demanded by new technology should match the available competencies of the operational staff ?An integrated information management system should be fully functional for both production management and diamond control purposes ?Operational feedback must be correctly evaluated to identify design, maintenance, training and operational issues so as to accelerate the maturity of the new technology within the time span of the sustainable operations project ?Project execution and technology maturity risks have to be evaluated and married to ensure risk mitigation by means of suitable project resource and contracting model selection.

Jan 1, 2003

By V. F. Parry

Subbituminous coal or lignite when stored in random riles or in ordinary bins in which the temperature fluctuates and air circulates quickly undergoes objectionable physical and chemical changes, which decrease the utilization value of the fuel and increase its tendency to ignite spontaneously. Slacking takes place, and the heating value decreases. Those changes are accelerated by fluctuations of temperature and by circulation of air through the storage space. When such coals are exposed to the weather they lose moisture rapidly. If evaporation from the surface of a lump proceeds at a faster rate than that at which it is replaced by moisture from the interior, the rate of shrinkage at the surface is greater than that at the interior; consequently stresses are generated at the surface which cause the coal to disintegrate. Likewise, when moisture is absorbed by the air-dried surface the outside layers expand at a faster rate than the interior, which results in further break-down. As these cycles are repeated the lump may disintegrate completely. Therefore, successful storage of low-rank coals depends on control of the factors that influence change of moisture.

Jan 1, 1941

The latest outcome of science is that aII bodies are composed of vibrating atoms or molecules. In almost all mineral bodies when changing from the gaseous or liquid condition to the solid, if the vibrating molecules are allowed free play, they arrange themselves in a symmetrical manner, and at a definite angle to each other: This angle varies with each system of crystallization. In a great many bodies this process may be brought about artificially, and the growth of the crystal watched. The most common method is to dissolve some substance in water or some other liquid, on slowly evaporating the liquid, the substance dissolved will solidify and the molecules will arrange themselves in their particular crystalline form.The element carbon crystallizes in two forms; as graphite in the form of a short six-sided prism', and in the diamond generally as the octohedron in the cubical system of crystallization. Orystalline bodies, as a rule, have plain faces but what is remarkable in the diamond is that in a great many cases the faces are rounded. Its great beauty as a gem when cut, and the high artificial value placed upon it by fashion, as well as its value as a cutting and boring instrument-it being the hardest body in nature-has caused many attempts to be made to form it artificially. These attempts have met with fair success as a scientific experiment, but as a commercial speculation they have been a complete failure. The most noted of these experIments was carried out by Mr. Hannay, of Glasgow.Paraffin spirit with lithium was submitted td prolonged heating in strong wrought-iron tubes securely welded. In most of the experiments the tubes exploded; but in a few cases the experiments were successful, and on cutting open the tubes small crystals of diamonds were found embedded in a black mass.Despretz produced minute diamonds under the influence of a powerful electric current from coal.

By Michael Michaylov

INTRODUCTUCTICN The coal seams at Bobov dol basin are highly prone to spontaneous combustion in Bulgaria. The risks of endogenous fires (SPONCOM) exist mainly in gob area. During the last 15 years three different technologies for preventing and fighting SPONCOM have been applied in underground mines of this basin: pulp from hard material and water, foam and inerting with nitrogen. On the basis of experimental application of these technologies as well as theoretical and experimental research a new technology - Foam Pulp Technology (FPT) was worked out. It is very effective in difficult to reach places in a gob. BACKGROUND AND THE NEED OF FPT Application of the three methods mentioned above showed advantages as well as some disadvantages, allowing determination of their effective application scope depending on geological and working conditions. Their advantages can be summarized as follows: - Foaming: high viscosity at low density, which allows forming a thick layer; good surfactant wetting properties; excellent effective cooling during evaporation in high temperature zones. - Pulping with mixture of solid particles (e.g., fly ash) and water from surface installation: easy to apply in a mine; low operational and energy costs due to gravity transport from the surface to the gob: good ecological results because the waste material is returned back underground. - Inerting with nitrogen: volumetric action which doesn't restrict the thickness of treated coal pile; easy to apply in a mine; controllable nitrogen delivery depending on fire hazard conditions. Main disadvantages of the same three methods are: - Foaming: rapid disintegration due to intrusion into heterogeneous and porous media and high costs due to the need of frequent large volume foam flows (short foam's life); - Pulping: inapplicable for coal piles with high thickness which is of great importance in the cases of seams with ununiform hypsometry (rapid and frequent changes in a seam configuration) and/or great volumes of coal or ore piles particularly heated to a high temperature; strong dependence on gob floor declination; water draining of the working face area which impedes the movement of supports and chain conveyor's. - Inerting: relatively high costs hardly depending on the rate of face advance (fig.1) in comparison with the other methods; it is difficult to ensure sufficient oxygen at the exit end of the face. This problem is crucial in faces with a high level of methane emissions; accelerating of the oxidation and spontaneous heating of the pile after turning off the nitrogen supply. Inerting should be applied again at higher capacity of nitrogen supply (fig.2) and what is more important, it shouldn't be

Jan 1, 1995

By A. von Röpenack

A forecast of the consequences of our techniques and goods produced, at least a technical assessment will be demanded from us as an industry. The hydrometallurgical winning of zinc is therefore at a crossroads. New processes promise not only better economics, better maintenance of resources and simpler operation, but also more harmony with nature. Pressure leaching promises to eliminate roasting and thus one complete process step. The hematite process solves a difficult and always costly iron problem. HOA opens a possible road to a totally new ,generation of electrolysis. Zinc has a long tradition behind it. Its? importance is as great as ever-. There is still room for new production developments. In my estimation there are good chances for successful new techniques? which will benefit our whole industry. Zinc is a modern and forward-looking metal.

Jan 1, 1990

By A Golsby

Both primary and secondary ventilation is important in underground mining. Secondary ventilation refers to the provision of ventilation to development ends, stopes and services facilities, which constitute secondary circuits tapped off the primary circuit or main through flow of air.An unbalanced primary and secondary combination can cause re-circulation, which is inefficient and potentially hazardous. These inefficiencies extend into operational and other considerations, such as power.Most cost justification analysis covers capital and physical consumables. These analyses are often not comprehensive or holistic. This case study is an example of ‘how to holistically justify’ a secondary ventilation circuit and optimise it to meet all stakeholder needs.This paper particularly addresses the following:how to account for all stakeholders in a secondary ventilation cost justificationthe secondary ventilation componentsthe cost justification outcomes and how to measure themsome of the sensitivitiesthe stakeholdershow to present the justification to meet the stakeholder needssecondary ventilation cost justification.CITATION:Golsby, A, 2015. Secondary ventilation as a value proposition – a case study, in Proceedings The Australian Mine Ventilation Conference, pp 49–54 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By Steve Dillingham

Here in the United States, as well as around the world, pose a daily dilemma - to wash or not to wash. Let’s face it, all trucks, especially our industry work horses - bulk trucks - get dirty. We all know that these units can be very expensive and washing them keeps your business investment looking new, improves public relations, fuels company pride, and facilitates equipment safety and preventative maintenance inspections.

Jan 1, 2001

The following pages contain valuable information about the products and services offered by our advertisers

Jan 1, 1982

By G. Warren

"In the past, smelting and refining of the precious metals recovered from ore has been generally looked upon as a small and relatively minor component of the business of gold mining. This is not surprising when one considers that the manpower, space and capital components of a gold refinery at an operating mine can be several orders of magnitude smaller than other unit operations at the same location. This philosophy is changing however, as economic and environmental pressure are forcing a re-evaluation of all aspects of gold mining and milling.This paper describes and evaluates three furnace technologies available and used by precious metal operators. The operation of arc, induction, and reverberatory furnaces are discussed and their strengths and weaknesses with respect to capital cost, impurity removal, slag quality, and environmental concerns highlighted.INTRODUCTIONIn the past, smelting and refining of precious metals recovered from ore has been generally looked upon as a small and relatively minor component of the business of gold mining. This is not surprising when one considers that the manpower, space, and capital components of a gold refinery at an operating mine can be several orders of magnitude smaller than other unit operations at the same location. Generally, gold producers will spend a great deal of effort to squeeze the last drop of efficiency out of a leach or grinding circuit via simulation or testwork but will design and build the refinery based upon past practices or industry standards. That past practices or industry standards will provide a functional refinery is undisputed; that this philosophy achieves the efficiencies that are possible or demanded in other plant operations is debatable.Environmental and worker hygiene requirements are considerations as well. Pollution control equipment can become a substantial contributor to both the capital and operating costs of a refinery and furnace selection has a marked influence upon the type and cost of this equipment. Slag characteristics and subsequent processing options available also play a role in furnace selection as precious metal slag losses and the recovery effort can greatly influence the cost / benefit analysis of a particular technology."

Jan 1, 2001

Australia is presently the world's principal producer of rutile and zircon, and also provides a major share of the world's ilmenite. Since 1980, Australia's share of the world's output of these minerals has fallen. Exhaustion of known resources, together with the changing composition of new deposits, is expected to result in Australia's share of the rutile and zircon output continuing to decline. Its role as a major supplier of upgraded ilmenite, that is synthetic rutile, is expected to increase. In 1994, the Bureau of Resource Sciences assessed Australia's demonstrated resources of mineral sands as follows: rutile 14.4 Mt, ilmenite 132.5 Mt, and zircon 21.0 Mt. These resources are located along the coast of Queensland and New South Wales, in the Murray Basin of New South Wales and Victoria, in the southwest corner of Western Australia, and in the Eneabba region, north of Perth. However, some 45 per cent of rutile and zircon resources along the coast of Queensland and New South Wales are not available for mining because of environmental concerns. World demonstrated resources are estimated at 40 Mt (contained TiO2) for rutile, 50 Mt for zircon and approximately 312 Mt (contained T1O2) for ilmenite. Outside of Australia, the most important resources of rutile, ilmenite and zircon are in South Africa (rutile, zircon , and ilmenite in the form of titania slag), Sierra Leone (rutile), India (ilmenite, zircon and rutile), and Canada (hard rock ilmenite). Significant resources of ilmenite occur in Madagascar and Mozambique.

Jan 1, 1996

By John K. Alley, Robert C. Johnson

The primary objective of the research was to grow aluminum borate whiskers or fibers and to determine their properties . Molten salt bath and vapor deposition methods were used for synthesis . Whiskers exceeding 25 mm in length were grown . The best results were obtained by vapor deposition and most of the data presented were determined on whiskers produced by this method of synthesis . Three different aluminum borate compositions ( 4.8A1203 B₂03 , 3.8A1203 B203 , and 2.5A120, B203 ) were identified by X- ray and chemical analyses . The aluminum borates 4.8A1203 B20, X- ray diffraction pattern was indexed . Optical data were obtained on the three aluminum borates . In addition the following whisker properties and growth factors were determined : ideal atmospheric dewpoint for vapor deposition method , near 65 ° F ; temperature range of whisker formation , 1,000 ° to 1,400 ° C for the molten bath method of synthesis , > 1,000 ° to < 1,400 ° C for the vapor deposition method ; whisker growth rates by the vapor deposition method , maximum 12 mm per hour ; raw material vaporization , 50 to 60 percent of the fluoride lost in 1 hour ; tensile strength , maximum obtained 174,162 psi ; melting points , ranged from 1,675 ° to 1,795 ° C.

Jan 1, 1965

By J. H. Van Reenen, H. Thiele, C. Bergman

For some time spirals have been the process equipment chosen to recover metal in the size range 0.15 to 3mm from ferrochrome and silico/ferro manganese slags. Recoveries of metal obtained using spirals are usually about 70%. Spirals are also difficult to control. By combining a novel gate on the Apic pneumatic fines jig with the recently developed Apic classifier, metal recoveries of 76% and grades of over 90% have been obtained for FeCr and SiMn slags in the size range 0.15 to 3 mm. The paper compares classifier operating performance and costs with those spirals for FeCr and SiMn metal recovery from slags. The classifier technology can also be applied to chromite and iron ores and coal fines.

Jan 1, 2004