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By D. M. MacLean

THE property of Howey Gold Mines, Limited, is situated at Red Lake, Ontario, one hundred and seventy-five miles east of Winnipeg and eighty miles north of the Canadian National railway. The mine has been a continuous producer since April, 1930, and, at present writing, a total of 3,042,690 tons has been hoisted, giving a production of $6,422,858.55, for a grade of $2.32 per ton. From 1,064,477 tons mined during the past two years, however, the yield has been only $1,389,607.03, or $1.41 per ton (gold at $20.67). Present output is at the rate of about 1,470 tons. per day. THE ORE-BODY AND WALL-ROCK: The Howey ore-body is part of a quartz porphyry dyke, which has. intruded an area of greenstone. The dyke strikes north 65° east, and its dip varies from 85° to the south at the surface to practically vertical below the. 1,000-foot horizon. Both along the strike and on the dip, the width of the dyke varies from 25 to 200 feet, the widest portion occurring below the 1,000-foot level. To the east of the ore-body, the dyke increases in width and finally splits into tongues of porphyry enclosed in greenstone, diorite, and congloJ11erate. To the west, it passes into the adjoining property, its width at the boundary being 100 feet. The rock in the ore-body is hard to drill, but, because of numerous horizontal slip-planes, it breaks well when blasted. This characteristic makes it possible to break large breasts or benches with a relatively small number of holes. The ore broken in this manner is consequently quite coarse, a large part of it requiring secondary breaking.

Jan 1, 1938

By D R. Seaman, B Adamson, F Burns, B A. Seaman, P Manton

The Telfer concentrator, located in the Great Sandy Desert of Western Australia, consists of a dual train gold/copper operation processing ore from one underground and, currently, two open pit mines with differing mineralogy. The flotation circuit of each train was designed to operate in several modes depending on the feed mineralogy. The majority of ore mined at Telfer is processed in a sequential mode where copper minerals are first floated into a saleable copper concentrate followed by the flotation of an auriferous pyrite concentrate which is treated in an on-site hydrometallurgical plant (carbon-in-leach (CIL)). Gold is recovered as a gravity product within the primary grinding circuit, to the copper concentrate, and to a lesser extent, the CIL circuit.Since Telfer was re-opened, with a new concentrator, in 2004, the processing plant has struggled with poor copper concentrate grades, partially due to the excessive entrainment of non-sulfide gangue minerals in the copper flotation circuit and, more recently, due to composite copper particles produced when processing ore from a supplementary satellite pit that has not previously been processed through the new Telfer concentrator. Gold recoveries in the CIL circuit have also been below industry standard. This paper presents the implementation of recent changes made to the circuit to address these performance issues. The reconfiguration of the circuit has involved the installation of the following major equipment items: two ISAMillsÖ in ultra-fine grinding applications (one in the copper circuit and one in the pyrite circuit), two Jameson Cells to improve fine gangue rejection and a bank of 5 + Outotec TC30s to recovery copper and gold from the reground pyrite stream. The equipment was purchased direct from vendors and an engineering firm contracted to design and install the multi-vendor reconfiguration upgrade.CITATION:Seaman, D R, Burns, F, Adamson, B, Seaman, B A and Manton, P, 2012. Telfer processing plant upgrade - The implementation of additional cleaning capacity and the regrinding of copper and pyrite concentrates, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 373-382 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By J A. van Niekerk, J G. Jardine, J W. Olivier

The Runruno Gold Project is located on the island of Luzon, approximately 200 miles north of Manilla in the Philippines. The mine is an open cut operation and uses the proven BIOX® and carbon-in-leach (CIL) processes to recover gold, and the ASTER™ process for detoxification of the CIL residue prior to discharge to the Residue Storage Impoundment (RSI). Work to date has defined a mineral resource of 1.39 million ounces (Moz) of gold, and the operation will produce 96 700 oz of gold per annum over a mine life of 10.4 years. The BIOX circuit is designed to treat 140 000 t/y of concentrate with a design capacity of 404 t/d of concentrate at a design sulfide sulfur grade of 17% S2-.The Runruno BIOX Plant is the first application of the Outotec BIOX Generation III design principles, focussing on ease of operation and maintainability. During development and implementation, the project team focussed on identifying opportunities to optimise the capital efficiency while not compromising on the operability or overall efficiency of the process or the equipment. The BIOX plant also incorporates the latest developments in the design of the BIOX agitators for more efficient mixing and gas dispersion. This paper will discuss some of the critical aspects and decisions taken during the development and implementation of the BIOX Process at the Runruno Gold Project. The paper will highlight some of the factors affecting the commissioning process as well as the improvements seen through the introduction of the Generation III BIOX design principles. CITATION:van Niekerk, J A, Olivier, J W and Jardine, J G, 2017. Implementation of the BIOX® process at the Runruno Gold project, in Proceedings MetPlant 2017, pp 218–228 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

By E. Asselin

Passivation of Fe-Ni-Co alloys during the Caron leach process is thought to result in low cobalt recoveries in ammoniacal ammonium carbonate solutions. A brief review of the available thermochemical data for the (Fe, Ni, Co)-NH3-H2O systems has been undertaken. The stability of the Co(II) and Co(III), Ni(II) and Fe(II) am-mines was examined through the use of speciation and Pourbaix diagrams at 298 and 333 K and at 6 M total ammonia. Increasing the temperature reduces the stability fields of the ammines and generally constrains the thermodynamic window for the leach. The Fe(II) ammines are only thermodynamically stable under reducing conditions. Polarization experiments show that these ammines are unlikely to form if oxygen is present. Fe-Ni-Co alloy passivation may be alleviated by careful management of potential.

Jan 1, 2011

By Elizabeth Anne Semon

The marketability of a large volume bulk material is significantly effected by transportation costs. Hence, it is essential for anyone that deals with minerals or mineral wastes to be able to reliably estimate bulk transport costs. The three types of bulk overland transportation modes that will be discussed are truck, railroad, and pipeline. Contract and private carriage are the two types of truck transport generally suitable for movement of bulk commodities. Contract carriers are those transportation firms that service a limited number of shippers and geographic points, and carry a restricted number of commodities. Private carriage consists of control over drivers and equipment by the shipper, ownership or lease of the transport equipment, and shipment of commodities related to the primary business of the shipper.1 A combination of private and contract carriage may also be used. Depending on the size and regularity of the shipment, rail offers single car, multiple car, or unit train service to move bulk minerals. Both long and short distance pipeline transportation has been shown economically and technically feasible for many different solids such as, mine and quarry products, coal, chemicals, copper concentrates, phosphate rock, and sewage sludge. 2

Jan 1, 1973

By J. E. Castle

The essential foundation upon which to build an effective marketing program in industrial minerals is the ability to produce competitively mineral products meeting precise customer specifications and to ship them promptly and on schedule. Without this prerequisite, all the other factors in a second marketing program-creative sales management, energetic solicitation, advertising, technical service, new products, etc.are without meaning. The primary image to be created in the mind of customers is that of the reliable and prompt supplier of mineral products at competitive prices and of standard, uniform quality. With this favorable image implanted, it becomes possible to integrate the other essential factors into a strong marketing program; and without this image, little can be accomplished. After having .made provision for the basic product ion position outlined, there are then two fundamental considerations in the design of a successful marketing program for industrial minerals. The first of these is that the number of potential customers for the typical industrial mineral product is, relatively small, and indeed compared to the number of customers for consumer products, the number is actually minute. The second consideration is that the customers for industrial minerals are manufacturers and producers rather than consumers. These two factors lead to a necessity that the marketing program be specifically and uniquely tailored to fit the individual mineral product to be sold and to conform to an existing pattern of distribution.

Jan 1, 1962

By T. T. Read, T. L. Joseph, F. H. Royster

In a preliminary study of the beneficiation of iron ores conducted by the Bureau of Mines, one of the authors (T. T. Read) found it necessary to ascertain, if possible, how much effect a decrease in the silica content of an iron ore has upon the cost of making pig iron from the ore. In the beneficiation of iron ores the most important impurity to be removed is usually silica, and the amount that can be expended on a beneficiation process to reduce the silica content of the ore is obviously determined by the amount of increase in the value of the ore after beneficiation. The price that can actually be obtained for a beneficiated ore is, of course, a matter of negotiation between the seller and the buyer, but since the relative value of different grades of iron ore must be chiefly based upon the cost of making pig iron from them, an approximation as to the effect which decrease in the silica content of ore has upon the cost of snaking pig iron is an important guide in estimating what probable average gain will result from subjecting an ore to a beneficiation process. A search of the literature failed to reveal any detailed statement on this important topic, but fortunately the data are at hand to permit making an approximate calculation of the probable effect. For the purpose of the calculation assume three iron ores with the following composition (natural):

Jan 1, 1924

By Charles M. Wilk

"Solidification/stabilization (S/S) treatment is used to treat hazardous wastes for disposal and in the remediation/site restoration of contaminated land . SIS is also an increasingly popular technology for Brownfield (industrial property) redevelopment, since treated wastes can often be left on-site and to improve the soil for subsequent construction. This paper discusses the applicability of the technology to various wastes, basic cement chemistry relating to SIS, tests used to design treatability studies and to verify treatment, basics on implementation of the technology in the field , and examples of SIS use at brownfield sites, including a former wood preserving site, former manufactured gas plant sites, a former electric generating station, and a shopping mall development.INTRODUCTIONSolidification/Stabilization (S/S) is a widely used treatment for the management/disposal of a broad range of contaminated media and wastes; particularly those contaminated with substances classified as hazardous in the United States. The treatment involves mixing a binding reagent into the contaminated media or waste. The treatment protects human health and the environment by immobilizing contaminants within the treated material. Immobilization within the treated material prevents migration of the contaminants to human, animal and plant receptors. SIS treatment has been used to treat radioactive wastes since the 1950s and hazardous waste since the 1970's (Conner 1990). SIS continues as a cornerstone treatment technology for the management of radioactive waste, hazardous waste, and site remediation and Brownfield redevelopment."

Jan 1, 2005

Over five decades ago Kitchener et al. in England and La Mer and Healy in the US were advancing our understanding and application of flocculants, primarily related to water treatment and filtration of sludge. This paper identifies the beneficial uses of flocculants in the mining industry and revisits some less common applications. Flocculants are used in unique ways in the mining industry: (a) to increase the effectiveness of sediment ponds to achieve discharge compliance; (b) to eliminate air emissions and costs associated with concentrate drying; (c) to reduce soil loss by applying a flocculant to erodible soils, and reducing wind and water erosion; (d) to remove/thicken metal precipitates in acid rock drainage treatment; and (e) to enhance clarification and thickening in mineral processing. The mechanism of how flocculants, coagulations and potentially-determining ions function is described and how their use can be controlled and optimized. The potential toxic effects of flocculants and coagulants when used to achieve effluent permit discharge compliance for suspended solids is discussed. A review of numerous best management practice (BMP) guidelines for the design and operation of sediment ponds treating mine site runoff to remove total suspended solids (TSS) and turbidity revealed an absence of a predictive methodology to address regulatory discharge compliance for TSS concentration, turbidity and flocculant-induced toxicity. An essential component of pond design is the need to determine whether flocculants and/or other settling aids are required based on the site-specific soil particle size distributions upslope of the pond. Procedures are provided to predict the need for settling aids and estimate pond discharge quality and downstream impact for TSS, turbidity, toxicity and sub-lethal toxicity. The need to develop BMP guidelines are discussed for (a) the application of flocculant to surface soils to reduce erosion, (b) the application of flocblocks to increase the ?sediment control? aspects of erosion and sediment control, as part of the mine site erosion control plan strategy and (c) the application of flocculant to silt socks to treat mine site runoff.

Aug 1, 2013

By Ralf Winterberg, Axel G. Nitschke

"Macro synthetic fiber reinforced concrete or shotcrete is seen by many design engineers as offering a viable alternative to steel reinforcement in tunnel linings. The technology is now commonplace for primary and permanent ground support in both mining and civil tunnel applications. It has for instance become the standard form of reinforcement in the Australian mining industry, and has been used for a majority of permanent tunnel linings in recent tunnel construction in Norway. Similarly, macro synthetic fibers are becoming a standard solution for the initial lining in the USA.The use of macro synthetic fiber offers innovative solutions, yielding robust and sustainable tunnel lining designs. Citing recent research and actual projects, this paper presents state-of-the-art design considerations for fiber reinforced tunnel linings relating to structural and long-term performance. Topics include seismic resistance, crack width control, corrosion and durability, as well as sustainment of performance with age.INTRODUCTIONMacro synthetic fiber reinforced concrete (MSFRC) and shotcrete (MSFRS) has reached maturity as an engineered material and is widely used in all forms of tunnel linings, for temporary as well as permanent ground support in both, mining and civil tunnel applications. In the Australian underground mining industry, it became the standard form of reinforcement, where 2014 literally marked the end of steel fiber use in shotcrete [1], and has been used for over 80 percent of permanent tunnel linings in recent tunnel construction in Norway. Similarly, macro synthetic fibers are becoming a standard solution for tunnel initial linings in the USA. Recent examples in civil tunneling are the Devil’s Slide Tunnel and Caldecott Fourth Bore Tunnel in California or the Anacostia River Tunnel Intershaft Connector Tunnel in Washington D.C. In addition, an increasing number of tunnels are adopting shotcrete permanent linings using macro synthetic fibers. Examples include the A3 Hindhead tunnel near Guildford in the UK and the North Strathfield Rail Underpass in Sydney, Australia [2, 3]."

Jan 1, 2016

By J. D. Forrester

In striving to develop this discussion about "Manpower for Industrial Mineral Industries" two fundamental classes of manpower are encountered. These are: 1) The Labor Force, comprised of unskilled and semi-skilled, nonprofessional personnel who participate in conducting economic, mineral deposit operations and; 2) The Professional People involved in the science, engineering, and management of such industrial enterprises. The commentary given here will be directed primarily to a review of the characteristics of the second or latter class. To pursue successfully a career as a scientist or engineer in today's industrial and social complex, it is necessary that technical knowledge must have been acquired by training and study in an institution of higher learning. Also, to act effectively, the individual must have achieved some degree of specialzation, although this element often is developed to most notable degree by post-graduate exposure and experience. In addition, and especially in the case of "management," it is desirable, indeed it is even necessary, that an individual recognize and appreciate the fundamental humanistic-sociological controls, and their nuances, as these elements exist to shape his total environment.

Jan 1, 1969

By Descarreaux. Jean

"The Abitibi volcanic belt was sampled along a cross section extending from Matagami to a point east of Rouyn. A few samples were also collected in Louvicourt township, Quebec. The major elements were determined for 344 samples, and rock names were defined using normative minerals. The analytical data were studied by means of variation diagrams. The Abitibi volcanic belt is characterized by rocks belonging to both the tholeiitic and calc-alkaline magmatic series, but they show some differences as compared to some typical reference series, particularly those from Japan. Basalt is the predominant rock type and accounts for 44 per cent of the sampled outcrops. The volcanic rocks are relatively poor in K2O and TiO2. Regionally, the volcanogenic copper-zinc mineralization is associated with the calc-alkaline volcanic sequences. Locally, within such sequences, some types of abnormal deviations from the averages are recognized only in association with the copper-zinc mineralization. The anomalies are ascribed to hydrothermal alteration consisting of the introduction of MgO and removal of N a20; enrichment in K20 is also observed where zinc mineralization predominates. Examples of such anomalous zones show that, in places, this alteration phenomenon can be quite extensive. Petrochemical characteristics can be used as geochemical ore guides in exploration programs."

Jan 1, 1973

By Dennis D. Fischer

The second underground coal gasification experiment conducted by ERDA's Laramie Energy Research Center at a site near Hanna, Wyoming, was completed on July 30, 1976. During the experiment production reached 0.32 Mm 3/d (12 Mft3/d) of 6.9 MJ/m3 gas (175 Btu/ft 3 ). Approximately 6100 tonne (6700 ton) of coal were gasified during the experiment. Energy return ratios of 4.5 to 5.3, cold gas - thermal efficiencies of 76 to 89 percent, and overall process efficiencies of 65 to 74 percent were achieved during the second Hanna experiment. This paper describes the experiment and the results obtained with emphasis given to the determination of the energy recovered relative to energy consumed in conducting the test. Data from this determination are compared with previously published data from the first test conducted at Hanna during 1973-1974.

Jan 1, 1977

By A Woodley, G Keir

The mining industry faces concurrent pressures of reducing water use, energy consumption and greenhouse gas (GHG) emissions in coming years. However, the interactions between water and energy use, as well as GHG emissions have largely been neglected in modelling studies to date. In addition, investigations tend to focus on the unit operation scale, with little consideration of whole-of-site or regional scale effects.This paper presents an application of a hierarchical systems model (HSM) developed to represent water, energy and GHG emissions fluxes at scales ranging from the unit operation, to the site level, to the regional level. The model allows for the linkages between water use, energy use and GHG emissions to be examined in a flexible and intuitive way, so that mine sites can predict energy and emissions impacts of water use reduction schemes and vice versa. This paper examines whether this approach can also be applied to the regional scale with multiple mine sites.The model is used to conduct a case study of several coal mines in the Bowen Basin, Australia, to compare the utility of centralised and decentralised mine water treatment schemes. The case study takes into account geographical factors (such as water pumping distances and elevations), economic factors (such as capital and operating cost curves for desalination treatment plants) and regional factors (such as regionally varying climates and associated variance in mine water volumes and quality).The case study results indicate that treatment of saline mine water incurs a trade-off between water and energy use in all cases. However, significant cost differences between centralised and decentralised schemes can be observed in a simple economic analysis. Further research will examine the possibility for deriving model up-scaling algorithms to reduce computational requirements.CITATION:Keir, G and Woodley, A, 2013. Regional trade-offs between mine water and energy use - a water treatment case study, in Proceedings Water in Mining 2013 , pp 21-28 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

By T. L. McCall

CHANGES in mining practices have evolved so quietly and unobtrusively that perhaps we scarcely appreciate how truly startling these changes are unless we cast our minds back so as to compare the past with the present. Such retrospection is, indeed, necessary when attempting to forecast the future, for it is only by carefully reviewing the past that we can hope to obtain an indication of what the future may hold in store. In this instance, it is not necessary to delve into the very early history of . coal mining, as our purpose will be served if the last three or four decades are reviewed, a period that is still fresh within the memory of many of us. These earlier days might be termed the selective period of mining, for at that time the coal resources of the world had not been tapped to anything like the extent they are at present and this condition enabled the owners and operators to exercise selective powers and only mine such seams of coal as could be most easily reached an worked at the lowest possible cost and which, at the same time, would suit the requirements of the market. Carrying this thought of selective mining still further, the miner, who was then an artisan skilled in all the branches of his calling, was able to select or discard such parts of the seam he was working that the co al sent out of the mine was acceptable to the consumer with just the barest minimum of preparation. Compare these conditions with the? conditions prevailing today, when coal seams of medium height, good quality, and readily accessible have been largely depleted and the operator has been compelled either to carry on his operations under much greater depths of cover where the coal is more costly to win, or else to work seams of lesser height or of poorer quality.

Jan 1, 1938

By A. H. Anderson

THE travelling grate coking process was developed by Shawinigan Chemicals, Limited, at their Shawinigan Falls plant. The first production unit went into operation a month prior to the outbreak of the war. Since then a substantial part of the coke used in the manufacture of calcium carbide has been produced by this process. In the following will be given a short account of the development work, a description of the process and the equipment, a discussion of the properties of the coke, the economics of the process and its future possibilities. EXPERIMENTAL WORK The carbide industry is a large consumer of coke, one ton of commercial carbide requiring for its production 1,200 lb. This coke must meet certain specifications in order to be acceptable. It should have a low ash content, preferably below 8 per cent, and the sulphur and phosphorus content must not be above specified limits. The size of the coke is also important. If it is too large it has to be crushed before it can be used in the furnaces, and if it is too fine it may have to be screened and briquetted. In addition, it must be dry. Although it was generally possible to purchase coke, including petroleum coke, and coke fines, in the quantities required, it became increasingly more difficult as time went on to obtain coke of a suitable quality at an attractive price. It was therefore natural for us to look to coal carbonization as a means of basing the supply of the fundamental raw material for carbide manufacture on something more solid than the shifting conditions of the coke market.

Jan 1, 1944

By V. Budinsky

In recent years the global mining industry has addressed its social and environmental responsibilities and numerous factors have contributed to this. Corporate Social Responsibility (CSR) is an important part of mining company strategy for practical implementation of the goals of sustainability, transparency, accountablity and good relationships with stakeholders:- investors, employees and communities. A key stakeholder for all mining companies is the local community which is affected by the mining operations. Companies must identify the emerging social and environmental trends, study the interests and concerns of various communities, address their needs and maintain a positive relationship. The CSR programmes of Czech coal mining companies are focused on surrounding community initiatives and sustainable responsible business. Mining in the Czech Republic is subject to strict rules and regulations and supervised by the State Mining Authority. Mining projects undergo rigorous approval procedures which encompass all operational measures at the different planning levels ? such as public participation in the authorisation process for mining projects, the application of the Environmental Impact Assessment Directive, environmental sustainability programmes, innovative solutions and flexible options offered by the mining company. One very important part is the preparation of the mining-technology preconditions and developing the integrated planning process in which all socially and politically relevant subjects in the mining operation surroundings are included. In an in-depth debate, all stakeholders may jointly develop the concept, in accordance with democratic principles. The optimally conducted dialogue process needs broad communication bases, including setting up theme-related joint taskforces, together with good moderation and the highly qualified support of technical experts. Using a case study of Severoceske doly a.s. Chomutov (SD Company) and the Czech Coal Group ? Czech leaders in the extraction of brown coal, this paper aims to examine the community development approaches and the CSR effectiveness of large scale mining companies. This paper brings a review of CSR and other such voluntary initiatives in the mining industry's proactive steps to contribute to societal well-being in a meaningful way. Key studies are provided by the projects ? Region with Better Perspective?, ?Stop Dust for Healthy Brezno Village?, ?Clever Heads for the North? and ?Coal Safari?. CSR issues are managed throughout all stages of the mine operation and beyond, long after the mine closes (e.g. post-closure programmes of new landscape, alternatives for reclamation including generation of lakes in former surface mines, conceptualization of industrial heritage). Communities need to be given the opportunity to help themselves through participation in CSR projects rather than being recipients of financial gifts from the company. A fair balancing of interests is the basis of any successful cooperation.

Aug 1, 2013

Alluvial diamond deposits covered with a thick overburden cannot be explored effectively and mined profitably with the available conventional techniques. A novel directional drilling technique has been developed and site trials have been conducted at the De Beers Namaqualand Mines situated at the western coast of South Africa. This paper describes the technique developed as well as the results of the site trials. The main task of the project is to develop a tool and a supporting system to achieve a remote exploration and ore extraction method for inaccessible alluvial diamond deposits. The project involves the acquisition of a system, commissioning on-site and evaluating the information obtained during assessment. The project consists of the design -of certain tools and instrumentation for the system, investigations and desktop studies as well as development of the system's logistics. The operating philosophy of the system is based on the keyhole surgery principle. In this study a pilot hole was drilled first, starting from the surface with an inclination to reach deeply seated diamondiferous gravel layers, followed by drilling into a more or less horizontal gravel layer for a certain length and finally pointing-upwards reaching ground surface at a predetermined exit point. The pilot drill bit was then replaced with a larger diameter reamer/mining tool and an HDPE tail pipe was attached behind the reamer. The drill string was retracted back to enlarge the guide hole and flush the excavated ore to the surface through the tail pipe. The material flow in between the sections of the system was' carefully measured to assess and record the gravel recovery rates. Several horizontal holes were drilled at preplanned drill paths to reach and follow the ore layer and the Ore extraction was achieved by means of a reamer/mining tool. Principles of the concept have been proven viable in this investigation.

Jan 1, 2010

By V. Barranco, K. Yliniemi, A. Hubin, B. P. Wilson, D. Janas, M. Lundström, P. Hannula

Typical copper electrorefining electrolyte contains tens of grams of copper, some nickel and a wide variety of impurities. Some of these impurities comprise trace amounts of dissolved precious metals like Ag, Pd and Pt that currently are not fully exploited. This study presents an electrochemical method to recover precious metals via a combined electrodeposition-redox replacement (EDRR) process, where energy is used only to deposit copper during the ED-step, while the RR-step relies on the spontaneous replacement of copper by the precious metals (i.e. cementation). In order to conduct the recovery successfully, process parameters such as deposition potential (EDE), deposition time (tDE), redox replacement time (tRR) and the number of cycles (n) was adjusted. Investigations performed in synthetic electrolyte (40 g/L Cu, Ag = 10 ppm) proved the possibility to recover a high purity silver. Short deposition times (tDE) were found to result in small Cu particles that provided a suitably high surface area for silver cementation. In addition, experiments performed in real industrial electrolytes containing 44 g/L Cu and 54 ppb Ag (Boliden Harjavalta, Pori), demonstrated that EDRR could attain Ag recoveries of between 46–67% in an energy efficient, additive-free manner. INTRODUCTION The raw materials used in the state-of-art primary and secondary copper smelters contain mainly base metals, but also notable amounts of Ag, Pt and other precious metals. These valuable metals distribute mostly into the copper matte during the pyrometallurgical treatment (Tirronen et al., 2017) and end up into the cast anodes. During the electrorefining stage, metals more noble than copper such as gold and platinum, are not dissolved but enrich into the anode slimes. In contrast, silver may dissolve slightly and thus, minor chloride addition is used to retain silver in the slime as sparingly soluble AgCl. Moreover, other metals less noble than copper may also dissolve, such as nickel. Therefore the electrolytes used in electrorefining typically contain substantial amounts of copper, nickel and even arsenic as well as minor metals such as antimony and bismuth. In the Boliden electrorefinery these were reported to be in the magnitude of 51.2– 60.4 g/L of Cu, 10.9–15.8 g/L Ni, 7.2–15.9 As, 0.2–0.4 Sb and 0.1–0.4 Bi with an associated sulfuric acid concentration of 139–155 g/L (Lehtiniemi et al., 2018). Copper is the most noble of the dominating base metals in the electrolyte and is thus deposited on the cathode as 99.99% purity LME-A grade. Anode slimes are collected and subjected to precious metals treatment e.g. via pressure leaching—selenium recovery— Doré smelting—Ag refining—Au/Pt/Pd leaching and reduction process (Ludvigsson & Larsson, 2003). The Pori refinery, operating in Finland since 1941, not only produces 133 000 t Cu cathode and 2300 t nickel sulphate annually but also 66 t silver, 4.6 t gold and palladium and platinum (in year 2017).

Jan 1, 2019

By J. Ouellet

"ABSTRACTA brief background on in-situ testing of mine backfill, as well as pressuremeter testing is briefly described, and results from an in-situ testing on paste backfill are presented. A series of self-boring pressuremeter tests were done from the top of a backfilled stope in an underground mine. The tests were conducted along a 20-metre vertical line in the centre of the stope. Some 14 tests were performed along this depth. The instrument used was a Camkometer built by Cam Insitu, Cambridge. The instrument proved to be efficient and reliable for underground testing in a cemented paste backfill. The testing program was conducted within the planned schedule with a high success rate. The test done in this study permitted the measurement of paste backfill strength, stiffness and in-situ horizontal stress within the backfill. RésuméUn bref historique des essais in situ dans le remblai minier est présenté. L’essai pressiométrique est décrit succinctement et des résultats d’une campagne d’essai dans un remblai en pâte sont présentés. Un programme d’essais au pressiomètre auto-foreur a été réalisé à partir du sommet d’un chantier remblayé sous terre. Les essais ont été réalisés le long d’un ligne vertical d’environ 20 mètres pour un total de 14 mesures. Le Camkometer de la firme Cam Insitu de Cambridge a été utilisé. Cet instrument s’est avéré efficace et fiable pour tester le remblai en pâte cimenté sous terre. Le programme d’essai s’est déroulé à l’intérieur de l’échéancier prévu avec un taux de réussite élevé. Ces essais ont permis de déterminer la résistance, la rigidité de ce remblai ainsi que les pressions in-situ prévalant dans le remblai."

Jan 1, 2000