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By R. Plassart, F. Laigle

"As a powerhouse, a transformer or a valve chamber, large underground caverns are a major element of hydropower plant. On the contrary to galleries and shafts which are linear and long underground structures, large caverns are designed with often complex geometries and large spans. Moreover, as these caverns are generally located on the foot of the hydraulic scheme, the high overburden is often responsible of a high stress state. Thanks to current experiences in France and around the world, the Hydro Engineering Centre (CIH) of EDF has defined great principles in the design of caverns leading to a more general methodology. The project of Tehri in India is an example of difficult ground, with in the same time a high overburden, a ductile material and an important schistosity. These physical realities are attempted to be approached in numerical modelling thanks to a constitutive law with softening behaviour and an oriented criterion integrated in the continuum model. As a result, a flexible support is advised, based on a high density bolt system and a thin lay of shotcrete. This methodology has been developed in the case of Gilboa in Israel, except the schistosity which has not been observed in situ. At last, the example of Gavet (France) illustrates a discontinuous case of numerical modelling for a good quality but fractured rock mass.PRINCIPES ET METHODES DE CONCEPTION DE GRANDES CAVERNESHYDROELECTRIQUES SOUTERRAINESRESUME Les grandes cavernes souterraines abritant les turbines, les transformateurs et certaines vannes sont des ouvrages majeurs dans les aménagements hydroélectriques. A la différence des galeries et des puits qui présentent de longs linéaires, les grandes cavernes sont des structures à la géométrie souvent complexe et avec des portées conséquentes. De plus, ces cavernes étant généralement situées en pied du circuit hydraulique, la grande couverture rocheuse peut se traduire par un état de contraintes important. Forte de ses expériences récentes en France et dans le monde, le Centre d’Ingénierie Hydraulique d’EDF a identifié de grands principes de conception des cavernes permettant l’élaboration d’une méthodologie plus générale. Le projet de Tehri en Inde est un exemple de terrain difficile, présentant à la fois une forte couverture, un matériau ductile et une schistosité marquée. Ces réalités physiques sont approchées au mieux grâce à la prise en compte dans les modélisations numériques d’une loi de comportement radoucissante avec un critère orienté intégré dans un modèle continu. Les résultats ont conduit à privilégier un soutènement souple basé sur un boulonnage systématique relativement dense associé à une fine couche de béton projeté. Cette méthodologie a ensuite été reprise pour le projet de Gilboa en Israël, exception faite de la schistosité puisque non observée sur site. L’exemple de Gavet (France) enfin permet d’illustrer un cas de modélisation numérique discontinue d’un massif rocheux de bonne qualité mais fracturé."

Jan 1, 2015

By C. H. Bucknam

Net carbonate value (NCV) characterization methods for acid generation potential measurement originated from studies on the Carlin Trend during the 1990's and have been subsequently standardized through cooperation of the Acid Drainage Technology Initiative Metal Mining Sector and the American Society of Testing and Materials International. The paper describes the evolution and standardization of the NCV methods, the importance of mineralogy in interpreting the results and application of the methods to implementation of the Global Acid Rock Drainage (GARD) Guide.

Jan 1, 2011

By J. Holtzhausen

"An analysis of operating costs for underground mining operations in the current global economic climate considers the financial burden for a ventilation system to be in vicinity of 30–50%. These operating costs are often overlooked by management teams in the greater scale of things when looking to save money in the procurement phase. This oversight to operational costs can be as little as the effective delivery of ventilating air to the work zone. One of the biggest opportunities for substantial savings and improvements can be realized in the selection of a quality vent duct that is suitable and fit for purpose. The key component to the selection process for quality products is a solid selection criterion that is followed during the tender process. This allows the management team to filter out unsuitable suppliers and products. The case study identifies some of the key components that were considered in the procurement and selection process for lay-flat ducting products. These included the characteristics and strength of the materials. The selection criteria also considered a ducted performance comparison that offers the best aerodynamic performance with some of the following components. • Airflow at Duct Face (m³/s or cfm), Fan Pressure (Pa), Air Power (kW or hp), Assumed Fan Efficiency, Annual Running Costs, K – Factor or Lambda, Leakage Factor, Joining Method and available Duct Lengths with weights. • Critical components considered were the current Testing standards available for: o Bursting Strength AS 4878.5, Mass AS 2001.2.13, Tensile Strength AS 4878.6, Tensile Strength AS 2001.2.3.1, Tear Strength AS 2001.2.10, Tear Strength AS 4878.7 • Other key considerations were: o Warranty Claim, Damage claims, Local storage / operations, community engagement and relationships, current testing data, previous issues, after sales service with technical assistance, etc. Hidden costs associated with product failures and operational stoppages are often not quantified during the tender process. Buyer beware. INTRODUCTION The largest constraint underground mining operations currently face are their operating efficiencies and electrical costs. The overall cost of an operations ventilation system and its components requires more focus to identify what opportunities exist to maximise efficiency and effectiveness. This tender process may not always be clearly understood and it should be broken down into fewer components to achieve quantifiable results."

Jan 1, 2019

By Dani J. Alldrick, Alastair J. Sinclair, Colin I. Godwin

"Abstract - The Stewart mining camp has a long history of precious and base metal mining. The camp is abundantly mineralized, with more than 200 widespread, varied, vein prospects, deposits and orebodies. These show wide variations in the mineralogy of ore, gangue and alteration assemblages, and wide variations in textures and structural settings. This report establishes the timing of the different metallogenic epochs and suggests a specific exploration application for systematic lead isotope analyses.Galena lead isotope ratios from a range of mineral occurrences indicate that all these varieddeposits formed during two main mineralizing events. Lead isotope data from the Stewart mining camp do not provide absolute ages for the formation of mineral deposits, but the relative distributions of data are consistent with dates determined in other studies. One ore-forming episode occurred in the Barly Jurassic and the other in the Middle Eocene. Both metallogenic epochs were brief, regional-scale phenomena. Sorne deposits from the younger mineralizing episode were em­ placed adjacent to or superimposed on the older deposits.Field and laboratory studies show that the two metallogenic epochs are characterized by different base and precious metal suites: Barly Jurassic gold-silver-zinc-lead-copper; and Middle Eocene silver-lead-zinc. Therefore, showings of different ages have different base and precious metal potentials and deserve different exploration emphasis. Lead isotope studies provide a reliable, cost-effective method for evaluating the age and commodity potential of small or recently discovered mineral showings and for setting exploration priorities on properties with several varied mineral occurrences . The determination of the age and metal potential of a prospect at an early stage of exploration may govern the urgency, intensity or even the necessity for further exploration work."

Jan 1, 1993

By Omero Alonso-Gonzalez, Sergio Haro-Rodriguez, Ricardo Solis-Rodriguez, Francisco Alvarado-Hernandez, Juan Antonio Gonzalez-Anaya, Héctor Rene Vega-Carrillo

"Precious metals are currently associated with refractory minerals such as telluride (Calaverite, Sylvanite, etc.) and selenium (Naumannite Ag2Se), which are difficult to dissolve through traditional methods, therefore it is necessary to perform a pretreatment (oxidative or roasting) preceding the process of leaching by cyanidation. In this preliminary work the aim was to study the use of solvent extraction to remove tellurium and selenium ions from a synthetic cyanidation effluent, with the purpose of recycling the cyanide back to the process. For the extraction of these anions, TeO32- and SeO42-, tallow trimethyl ammonium chloride (Quatarmina TPR) and hexadecyl trimethyl ammonium chloride (Amine F) were studied as extractants, using nonylphenol as a modifier in the organic phase (trimethylpentane). The results show that it is possible to recover 82% of selenium and 10% of tellurium from synthetic solutions containing either 20 mg/L Se or 20 mg/L of Te, respectively The Se or Te mole ratio to cyanide was 1:4.INTRODUCTION In relation to extraction of precious metals, the cyanidation process has been in use for over a century and despite environmental and toxicological problems it remains the most widely used and economical process available. In the late 90s, there were great efforts to recover gold and silver from refractory ores, which is difficult to do by simple cyanidation. To improve gold recovery from tellurides and selenides that occurs in some new mines, the ores are pretreated by roasting. This is one of the most effective ways of rendering refractory gold ores leachable as well as being a fast pretreatment process compared with bio-oxidation or pressure leaching (Aylmore, 2001). The most important tellurides minerals are Calaverite (AuTe2) and, Silvanite (Au, Ag)2Te4). In the case of selenides, minerals include Naumannite (Ag2Se) and Aguilarite (Ag4SeS) (Ostroumov et al., 1989). Examples of deposits containing telluride include La Bambolla Mine (Sonora, Mexico), Cripple Greek (Colorado, USA), and Kalgoorlie (Western Australia) (Aguayo et al., 1996). The main purpose of this work was to explore the feasibility of using quaternary ammonium salts such as: tallow trimethyl ammonium chloride (Quatarmina TPR) and hexadecyl trimethyl ammonium chloride (amine F) to extract tellurium and selenium anions from aqueous synthetic cyanidation effluents, so that the cyanide solution could be recycled back to leaching process. The tests were performed on synthetic solutions similar to those found in a mine: 20 mg/L Te as TeO32-, 20 mg/L Se as SeO42- and mole ratio to cyanide was 1:4. using an alkaline medium with pH ranging from 8 to 12. Two aspects are evaluated in this paper:"

Jan 1, 2017

By Dave M. Jakelski, Gerhard W. Heinrich, Peter F. Wells, Daniel F. Suarez, Jamie B. Beauchamp

"A need for increased copper concentrate production and for less nickel contamination in that concentrate at Falconbridge's Strathcona Concentrator during 1993 required the installation of a third flotation column and improvements in the operation of the existing circuit. Innovations in wash water distributor and launder design were fundamental in achieving objectives on a new 3 meter diameter column. Minnovex plug-type spargers were tested on a 2.1 meter diameter column in order to reduce maintenance requirements. The paper details the measures taken to enhance column flotation circuit performance and the results obtained.IntroductionFalconbridge's Strathcona Mill receives 10% of the ore feed from a rich copper zone in the Strathcona mine. This ore typically grades 7% copper and 1 % nickel and, because of its high copper content, it is processed in a separate circuit ('C' circuit) which consists of conventional grinding, rougher flotation with the concentrate being treated with lime to pH 12.3 and cyanide followed by column flotation. The columns are operated with mechanical flotation scavengers and the scavenger concentrate is returned to the column feed. Testwork conducted in 1991 showed that the original flotation column (Column 2) could only produce 5.5 mtph of concentrate with less than 0.5% nickel (Figure 1).Between 1991 and spring of 1993, production was increased at times by open circuiting the scavengers. Metallurgical improvements were obtained by improving the wash water distributor of Column 2 and by wash water sprays in conventional cells (1 ). However, the scavenger concentrate assayed 0. 7 -0.8% nickel and was not acceptable for long term operation. When Copper ore production targets were significantly increased for 1993, it became clear that an additional flotation column was required. The new flowsheet employs mechanical scavenger cells on the column tails as in Column 2 circuit (Figure 2). A -parallel configuration was chosen as pulp solids fraction has been shown to be a critical variable and the second column in series would receive a lower density feed."

Jan 1, 1994

The Autogenous milling of ores holds an increasing attraction as the focus moves towards reducing energy usage, both direct and embodied in grinding media. However, most of the early AG mills were converted to SAG for improved stability and increased throughput. This imposes a huge penalty in steel grinding media consumption. The LKAB iron ore operations in Sweden process highgrade magnetite through fully-autogenous milling lines to a final product P80 of about 45µm. The outcomes of P9O AMIRA research surveys, covering a wide range of mill fillings and throughputs and with different feed blends, are presented. Insights are provided on operational strategies, opportunities, the influence of feed size control and balancing the blend of competent gangue and softer magnetite. Areas of importance in the successful operation and control of energy-efficient autogenous circuits are highlighted.

Jan 1, 2012

By Getu F. Biftu

There is general agreement among scientists that global surface temperatures have been increasing during the past decades. The increase in temperature is postulated to be the result of either an increase in greenhouse gases emission or climate variability (i.e., due to variations in sun or volcanic activity or El Nino and La Nina events) during past decades and may continue to increase. The effects of a predicted rise in the Earth?s surface temperature include an increase in average global evaporation and increase or decrease in precipitation (Bloomfield, 1992; Mann et al., 1991; Vinnikov et al., 1990; Gan 1995; Zhang et al., 2000a). The general circulation models (GCMs) project a global warming due to greenhouse effects of 1.5-4.5°C by the mid 2050s, with the most pronounced changes taking place in northern latitudes (Nicholls et al., 1996). However, similar predictions at a watershed scale or even a regional scale using GCMs are mot possible yet (Arnell et. al., 1996; Georgievskii et. al., 1996; Zhang et al., 2000a). Detection of historic trends, changes and variability in climatic variables is another indirect means of understanding potential future changes or variability at regional and local scales. The main objective of this paper is to review studies related to climatic change or variability and associated hydrologic changes at a regional scale and local scale, particularly those studies applicable to the Oil Sands Region (OSR) of Alberta. This paper identifies gaps in our current understanding of the hydrologic processes that may be affected by climate change; it discusses potential implications to developments in the OSR; and it explores mitigation opportunities including several that have already been implemented.

May 1, 2004

By T. T. Ni

FOR MORE THAN 200 years, the Kochiu district of Yunnan province has been, and it still is, the hub of China's tin industry. The district produces annually from 80 to 90 per cent of that country's out-put of tin, which averages about 9,300 tons a year and places China fifth among the tin producing nations of the world. The tin ore reserves of the country are estimated (1) at 1,873,370 metric tons, of which 1,500,000 tons are in the Kochiu district. The mill of the Yunnan Consolidated Tin Corporation, described in this paper, is the only one of its kind in China. MINING AND SMELTING There are only two tin mines in the Kochiu district operating with modern equipment -the Hsin-Chang and the Lao-Chang, both owned by the Yunnan Consolidated Tin Corporation, a government company. The Hsin-Chang mine has four working levels with cross-cuts 6 ft. by 6 ft. and is equipped with steel mine cars and trucks to haul the ore. The ore is hoisted to surface in a three-compartment shaft and transferred to the mill by a 4-kilometer aerial tram. The Lao-Chang mine has two circular shafts 656 feet apart, each equipped with two cages. Haulage-ways 1,600 meters and 1,000 meters long, respectively, have been driven to the southwest from these shafts and are connected by three cross-cuts.

Jan 1, 1951

By Charles Amoah

Abosso Goldfields Limited has been optimizing the comminution circuit at the Damang Mine Operation for the treatment of 100% primary ore. The optimization process started at a base rate of 343 tph when treating primary crushed primary ore, and was increased to above 600 tph with partially crushed primary ore. Abosso Goldfields engaged Orway Mineral Consultants (OMC) to assist with the optimization process in 2009 and the two companies have been working together since, to further refine the process. Continuous improvement was achieved through crushing circuit modifications, changes in operating processes and grinding control system utilization. This paper discusses the improvements developed for the increase in milling capacity and improvements in final product size.

Jan 1, 2012

By Unkown

To the Membership of the Institute Gentlemen: The Mineral Industry of Canada in 1948 The preliminary estimate issued by the Dominion Bureau of Statistics and tabulated in the Bulletin of January, 1949, indicated that the value of Canada's mineral production in 1948 reached an all-time high of $808,180,216, showing an increase of 25 per cent over the previous record of $644,696,007 established in the preceding year. The output value of metallics was increased by 22.4 per cent; of fuels, by 43.7 percent of other non-metallics, by 19 per 'cent; and of structural materials, by 16.8 per cent. The value of metals produced in 1948 at $483,770,759, was about $87,000,000 more than in the previous year. There were substantial increases in the tonnages of copper, lead zinc nickel, and other base metals produced, but the rises in market prices for such metals accounted for most of the gains in output values. Production of gold at 3,495,403 ounces valued at $122,339,105 indicated an increase in volume of approximately 500,000 ounces and an increase in value of 14 per cent. Despite the benefits provided under the Emergency Gold Mining Assistance Act 1948 the volume of gold produced in the year was still nearly 2,000,000 ounces less than the record of 5,300,000 ounces established in 1941. The value of mineral fuels produced in 1948, at $158,787,255, was 44 per cent above the 1947 total. Coal production at 18,431,250 tons valued at $107,298,757, while substantially higher than in the preceding year was still half a million tons below the record reached in 1942. Striking developments in the Leduc field in Alberta were responsible for bringing the output of crude petroleum in the year to a new high of 12,098,166 barrels, valued at $36,858,959.

Jan 1, 1949

By J. Schick, V. Granger

Nowadays, all French former uranium mining sites are remediated and redeveloped. If needed, mining waters containing radium have to be treated before discharged into the environment. Classical radium treatment consists in a (Ba,Ra)SO4 salt precipitation and radium monitoring was carried out using a time-consuming analysis called emanometry. Three zeolite samples have been tested to remove 226Ra from mining water. In batch experiment, radium was totally (R=100%) and quickly removed after 2 minutes contact time. Continuous sorption experiments were carried out through a vertical column at lab scale. Chabazite is the most efficient zeolite with an 226Ra activity below 0.2 Bq/L until 60000 Bed Volume. Chabazite is always efficient although radium content in material reaches 150 Bq/g. 226Ra uptake was also tested at semi-industrial scale on a pilot plant. More than 3000 m3 were successfully treated with a radium content below 0.1 Bq/L. The environmental impact assessment of Ra-chabazite was characterized by using batch leaching tests made according to the NF EN 12457-2 standard as applied on all wastes. Ra-chabazite stability is excellent during this test: radium leaching is very low, less than 0.005%. A new 226Ra measurement method was developed by ICP-MS for a better analysis reactivity. This new method was carried out in a couple of minutes with a lower sample volume than emanometry. The validation was performed according to the French NF T90-210 standard for the calibration function definition, the limit of quantification, the accuracy and the interferences.

Jan 1, 2020

By A. Scheltema Beduin, H. Oterdoom, A. Haaks, C. Kempe, A. Liedtke

"For the Kazchrome DC Ferrochrome plant, SMS-group specifically designed an electrode column that would minimize downtime. Special features include the possibility for on load electrode jointing, on load slipping, and back-slipping. Electrode consumption is strongly related to furnace load and impedance, and is very low at high loads, which makes the graphite electrode an alternative to consider even in AC applications. The electrode could also be applied in other DC applications, as for example TiO2 slag, the novel Conroast process, or (twin) DC FeNi furnaces, and could possibly be installed during bigger shut downs. This paper will describe some of the design considerations and operational performance data on this novel column in the FeCr industry that could also be of interest for the FeNi or PGM industry if these would continue to develop towards DC technology.INTRODUCTION Every DC furnace has a cathode and an anode. The anode applied is commonly known as the Concast design, though the original design was by ABB who handed it over to Concast, subsidiary of the SMS-group. Some well-known DC furnaces outside the steel industry where the Concast bottom has been installed are listed in Table 1 as well as a few other key design features.Sidewall cooling and some other data have been left out for reasons of space, and being a lesser relevant design feature to this paper. HES stands for Hollow Electrode System, in which feed is charged through an electrode. Table 1 is built up chronologically according to first start-up date. Below comments are given to briefly explain some of the columns in Table 1: •,“Arm” in the “Cathode” column means that the design of the cathode holding and regulating mechanism consists of an electrode arm as depicted in Figure 1. •,Charging is relevant as some operations started with HES charging, whereas recently most new operations have started without HES but only charging chutes, of which at least some are close to the electrode and possibly others installed closer to the sidewall. •,“Dome” in the “Roof” column means that the design of the roof involves a center piece that can be exchanged if worn. •,The optimal roof design still seems to be a topic of debate, where no design is without problems."

Jan 1, 2017

By C Carbonneau

In order to successfully produce columbium pyrochlore concentrates, St. Lawrence Columbium and Metals Corporation had to face two principal problems met in several new operations but possibly made more acute than usual owing to the newness of the project. 1.-The ore is particularly complex, as it is made up of an elaborate intermingling of carbonates and discontinuous ultra-alkaline rock bodies of various ages and types in which no less than seventy mineral have been re-ported. Obvious petrographic or structural controls are lacking. Ore boundaries have to be defined on the basis of assay results and the determination of several minerals which occur in trace amounts. 2.-The pyrochlore concentrates produced had to com-ply with a set of stringent specifications. This fact, combined with the low Cb205 content of the ore, necessitated the use of a beneficiation process that would have to operate at a concentration ratio greater than 100:1. A brief description of the mill circuit is given. Mill stability was obtained through extensive mineralogical study of the mill feed coupled with close geological and engineering control of the mining operations.

Jan 1, 1965

By Paul W. Shelley, Daniel J. Hodges

The mining industry is undergoing a period of rapid transformative change.  This is the result of the social and financial accountabilities that the industry is faced with because of the world’s desire to cap average temperature increase to 1.50C above pre-industrial levels (UNFCC, 2016).  To limit global warming to 1.50C, greenhouse gas emissions must peak before 2025 at the latest and decline 43% by 2030.  In hard rock mining, comminution is identified as the major energy consumer, being responsible for 40-60% of the electricity use.  It follows that comminution is the major greenhouse gas emission process of the mine.  All effort is being made to radically reduce the carbon emissions of comminution. Grinding media plays a large role in the energy consumption and carbon emission story.  In recent years industry practitioners have attempted to quantify the grinding media carbon footprint.  This paper makes a definitive contribution to that discussion.  The grinding media carbon footprint is quantified in Scope 1, 2 and 3 emission terms in the context of a grinding media supplier.  Major emission contributors, steel, natural gas and electricity are discussed in detail.  The steel industry transition is a key factor. The paper will explore the steel industry transition and its effect on grinding media manufacturing.  The carbon footprint of heritage steel process routes are analysed and compared with the process routes of the future.  Emerging steel making technologies are presented and discussed.  The future of the steel manufacturing and procurement route for grinding media is proposed. This narrative allows for a comparison between the heritage carbon footprint and the future carbon footprint of manufactured grinding media.  Of equal importance is the opportunity of reducing the grinding media carbon footprint in the field.  The paper explores possibilities of reducing the grinding media carbon footprint at the customer site.  Media in use options are presented that take account of the mineral characteristics, the mill dynamics, and the product metallurgy to optimise both carbon footprint and media performance. It is intended that this is a landmark paper in the discussion of the carbon footprint of grinding media.

May 4, 2025

By T. F. Pugsley, D. Gignac

"The historical background to the project dates back to the mid-30s with the discovery of surface sulphide showings in the Cape Smith-Wakeham Bay ultramafic belt. In the mid1950s, orderly exploration commenced with an extensive work program by Asarco, INCO, Lemoine, Falconbridge and Raglan Nickel Mines Ltd. on exploration permits. In 1966, Falconbridge and Raglan Nickel Mines interests merged. Extensive exploration, drilling, under- ground delineation of the Donaldson orebody and the construction of basic infrastructure such as camps, airfield, road links from Douglas Harbour to Donaldson and Katinniq, a distance of 60 km, were completed.Production project design at that time consisted of plans for a 50 000 mt per year nickel mining and concentrating operation, including a 2000 person community and smelter at Douglas Harbour. These plans unravelled in the mid-70s due to high capital costs, poor nickel market conditions and the realization that the Raglan orebodies were not large enough to economically support the construction of green field smelter and refinery facilities for processing Raglan production. Nickel market conditions in the late 70s and early 80swere generally poor, resulting in further delays on production plans.While recognizing the very high potential to discover increased tonnages of high grade(3% Ni) in excess of 20 million tonnes, the project was deferred into the late 80s when a serious re-evaluation of exploration potential occurred and the requirement to prove up additional reserves resulted in an underground exploration program at Katinniq covering the period 1990-1992."

Jan 1, 1996

By J. -C. Parisien-La Salle, D. Blais, G. P. Demopoulos

"In this work the dissolution, precipitation and adsorption behaviour of gold in acidic iron sulphate media containing small amounts of chloride ions is investigated via batch laboratory tests and OLI thermodynamic calculations over the temperature range 25-250°C. Chloride ions may be present in industrial pressure oxidation/pressure leaching (POX/PL) operations due to elevated water salinity levels or due to intentional addition as is the case of the CESL Copper Pressure Leaching Process. Thermodynamic calculations show that AuCl4 - may form depending on the free Cl-/Au ratio and temperature, its stability increasing with increasing Cl- concentration and decreasing with increasing temperature. On the other hand during POX/PL, we know that massive precipitation of iron in various hydrolysis products and compounds occurs. Hence of interest is the question how AuCl4 - that may form during leaching interacts with the iron precipitation products. Gold(III) chloride was found to co-precipitate with iron(III) (oxy) hydroxides and arsenates forming in the autoclave but not with natrojarosite. Upon further investigation it was discovered that activated carbon added in the autoclave (as done in CIL) acts as preferential sink for the mobilized gold, hence opening the potential for the development of a direct cyanide-free gold recovery process in acidic sulphate leach reactors.INTRODUCTIONThe recovery of gold from ores and concentrates has evolved over the years with processing routes becoming increasingly complex. Given the high value of gold, any reduction in losses during recovery operations constitutes an important economic benefit. One such loss that needs to be addressed is the potential solubilisation of gold during pressure oxidation (POX) of refractory sulphidic gold feedstocks. For example, Agnico Eagle Mines reported a loss in gold recovery due to the formation of a gold chloride complex (Garofalo, 2009). Gold is known to form complexes in solution, such as gold(III) chloride, if an excess of chloride ions are present. The fate of such soluble gold chloride during pressure oxidation and the subsequent neutralization of the acidic discharge slurry will determine if gold is lost or recovered in the downstream cyanidation operation. Thus it is of interest to know under what conditions gold chloride may stay soluble or co-precipitate along primary (formed in the autoclave) or secondary (formed during neutralization) precipitates. Furthermore, the mode of co-precipitated gold, such as adsorption on iron compounds, like goethite and hematite (Machesky et al., 1990; Nachayev, 1984); substitution in one of the precipitated phases; or finally chemical reduction to metallic state would have consequences in terms of gold recovery."

Jan 1, 2012

By Alan Bauer

New developments in drilling, blasting and explosives in both open-pit and underground mining operations are discussed, as well as novel surface blasting techniques such as are used in tar sand mining.

Jan 1, 1978

A brief description of the hydro-gen reduction of nickel from ammoniacal solutions by the Sherritt process is given, indicating how this procedure can now be used to coat a great number of materials -particularly powders -with nickel or cobalt, whereby so-called composite powders are produced. The technique for the production of composite powders is described, particularly with regard to the surface activation of noncatalytic powders, whereby it is possible to coat core powders uniformly with nickel or cobalt. The properties of some of the more interesting composite powders, such as Ni/ AI, Ni/WC, Co/WC, Ni/Graphite and i/P, are discussed as well as possible fields of application for these new products. INTRODUCTION DURING the last decade, no-table advances have been made in pressure hydrometallurgy, so that large quantities of three of the more com1r.on metals, copper, cobalt and nickel are now produced on a commercial scale by hydrometallurgical processes.

Jan 1, 1963

By Clemens Kuhnert

"Nickelhütte Aue GmbH is specialized in the recycling of waste materials containing non-ferrous metals. We treat nickel, copper, cobalt, vanadium, molybdenum and precious metal containing materials like spent catalysts, ashes, dusts, grindings, liquids, slurries and sludge's as long as they contain one or a combination of the above mentioned metals. In our pyrometallurgical works we produce non-ferrous metal concentrates suitable for further treatment in our hydrometallurgical plant where we refine Ni-, Cu-, Co- and V-chemicals. Our production is based on synergy effects due to the combination of pyro- and hydro-metallurgy. As an example we can mention our heat recovery system and internal recycling of by-products. Furthermore, the use of alternative fuels instead of fossil fuels contributes to the economic and environ-mentally friendly treatment system.INTRODUCTION Nickelhütte Aue GmbH (NHA) can look back on nearly 400 years of tradition as a pyrometallurgical works and recycling company. The existence since its foundation in 1635 as a blue dye works shows responsible and successful action in the past. Therefore, we see highest customer service, minimization of interferences with nature by closing material cycles and maximized health and occupational safety protection by avoiding injuries and diseases, still as our future duties. These duties are evaluated and monitored by an integrated management system that meets the standards of DIN EN ISO 9001, 14001, 50001 and BS OHSAS 18001. We commit ourselves to the observance of all juridical and customized demands. The management and the department managers perceive their model function. We require responsible action from all employees. To protect the continuity of our enterprise, we will also perform in future continuous improvement of products and their quality, as well as steady progress in the areas of environment protection, health protection and industrial safety. Equally the effectiveness and propriety of the management system is checked and developed regularly. In order to obtain the objectives resulting from this policy, our company determines activities and measures by involving all employees."

Jan 1, 2017