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By O. G. Olvera, D. G. Dixon, E. Asselin, L. S. Quiroz

Dissolution rates of chalcopyrite (CuFeS2) were calculated using electrochemical impedance spectroscopy (EIS). The calculated dissolution rate decreased by a factor of 3.2 after the electrode was passivated. The results presented in this work indicate that the reduction of Fe3+ was the rate-controlling step for fresh CuFeS2 electrodes while the transport of cations within the passive film limited the dissolution rate for the passivated electrode. The transfer of cations at the electrode/electrolyte and passive film/electrolyte interfaces did not affect the dissolution rates of the fresh and passivated CuFeS2 electrodes, respectively. The catalytic effect of pyrite (FeS2) on the dissolution of CuFeS2 continued after the passivating treatment. The contact of fresh and passivated CuFeS2 electrodes with different FeS2 particles resulted in increased dissolution rates, due to an increase in the reduction rate of Fe3+.

Jan 1, 2014

By Güney

"An investigation carried out to determine the tendency of coals to heat spontaneously in terms of time-temperature curves coupled with the resulting oxidation products in an adiabatically controlled laboratory setup is described. Tests were made at differing moisture conditions, including oxidation and also oxidation with either adsorption or desorption of water vapour on coal.From the experimental evidence, there is reason to believe that the oxidation of coal, although an important factor, is not the predominant one in the development of spontaneous heating. In addition to the temperature increase in coal and the gaseous products evolved due to auto-oxidation, the process is accelerated by adsorption and retarded by desorption of water vapour on coal."

Jan 1, 1971

By A. M. Esteves

This paper offers an overview of local content policies and practice in the mining sector. Specifically, the paper aims to answer the question of how national and regional governments, industry and civil society can work together to seek an optimal outcome while pursuing their diverse objectives. The paper begins by defining local content and its scope at the subnational level. Specific recommendations for the design of local content policies to mitigate social, economic and governance risks are developed. The document then offers some recommendations regarding the role of partners in design, implementation, monitoring, and enforcement of local content policies.

Aug 1, 2013

By G. B. Harris

It has long been appreciated that chloride chemistry has a number of advantages over the more traditional sulphate route for both extracting and separating metals. Modern materials of construction, coupled with the development of a more cost-effective and efficient hydrochloric acid regeneration technology mean that chloride-based processes are now more competitive and attractive. Such processing routes are able to recover more of the contained metal values in a feed, including iron in a benign and/or marketable form, and particularly the so-called rare and rare-earth elements which are increasing in demand in our electronic age. These factors, therefore, add appreciably both to the overall economics of a project, but also offer a much more sustainable approach to our dwindling natural resources. Additionally, chloride-based flowsheets can be much more environmentally-friendly, offering practical alternatives to two of the biggest headaches faced by the industry, namely cyanide usage and the generation of red muds. This paper presents a brief theoretical background, focusing on the latest developments of ferrous iron oxidation and the low-temperature, selective hydrochloric acid regeneration process, which is the key unit operation for any chloride flowsheet, and discusses in general the advantages of the chloride approach. Several recently-developed flowsheets, which have been tested at the miniplant level, are presented for gold, base metals, titaniferous magnetites and lead-silver ores wherein the advantages of considering a chloride approach are highlighted.

Jan 1, 2014

By Robert J. Mitchell

A general approach to mine backfill design, including laboratory testing procedures, is outlined in this paper. Relationships between certain design parameters are developed and the effect of other factors is discussed. It is concluded that the inclusion of backfill design calculations at an early stage of mine design can often produce over-all design economies. Not only are the data needed for backfill plant and tailings disposal area design, but also the pillar recovery method and over-all mine stability are dependent on the attainable fill properties.

Jan 1, 1979

By D. M. Richards

"IntroductionThe Highland Valley Copper partnership was formed in July 1986 as a logical result of a mine with a large ore reserve but a small mill, and a mine with a large, modern mill but dwindling ore reserves. The original partnership of Cominco and Rio Algom was expanded in January 1988 to include Highmont Mining Company. During 1988/89 the Highmont mill was moved 7.5 km to adjoin the Lornex mill, becoming the Highland mill in the process, with a nominal capacity of 130 000 tonnes per day.The mine is located near the town of Logan Lake, 220 km northeast of Vancouver, British Columbia and 55 km southwest of Kamloops. The map in Figure 1 shows the general area. Kamloops is a major service centre and is served by two railways, two major roads and a regional airport. The mine site is situated between 1200 m and 1600 m above sea level on the Thompson Plateau. Principle activities in the area, in addition to mining, are cattle ranching and forestry. Ore reserves at the beginning of 1996 totaled 533 million tonnes at a grade of 0.42% copper and 0.008% molybdenum. Ore is mined from two pits — Valley, 3 km northwest of the mill; and Lornex, 1 km southwest of the mill. With 78% of the reserves, the Valley pit is the focus of activity.In order for Highland Valley Copper to remain competitive with a very low grade ore reserve, it has been necessary throughout the mine’s life for new technologies to be embraced as they become available. These have included such diverse technologies as in-pit crushing and conveying, large mechanical drive trucks, computerized truck dispatch and oneman survey instruments. During the next few years, it is planned to introduce two further technologies that are relatively new to both the world at large and the mining industry in particular. These are namely Global Positioning Systems (GPS) and Geographical Information Systems (GIS), both of which are expected to have a major impact on the way mining is carried out in the years to come."

Jan 1, 1997

By A Frydrychewicz, J. Mirza, J. Lipkowski

The objective of this work was to understand the mechanisms of action of additives, such as thiourea, that enhance gold leaching in thiosulfate solution. The leaching reaction and surface passivation were investigated using linear sweep voltammetry. Leaching currents were determined using analysis of current-potential curves and the mixed potential theory. The gold-electrolyte interface was further characterized with surface enhanced Raman spectroscopy. The results show how thiourea prevents formation of oxysulfur compounds, which passivate the gold surface. Other molecules such as 3- m ercaptopropionic acid and L-cysteine were also studied as possible additives to prevent passive layer formation.

Jan 1, 2011

By Selwyn G. Blaylock

I.-THE HISTORY OF THE SYSTEM TO trace the history of the development of the Co-operative Committee System in The Consolidated Mining and Smelting Company of Canada, Limited, one must look backward about twenty years. In 1915 and 1916, the first years of the W ar to really affect Canadian life, there were sixteen hundred men working in the Trail plant. These men were, on the whole, a splendid body of men and pa trio tic to the core. They were almost one hundred percent organized, ninety-five percent of them be-longing to the Union of the Western Federation of Miners. Most of the tradesmen belonged to their craft unions as well. For example, there were ? local machinist, steel workers', electrician, boiler maker, bricklayer, and carpenter unions. The Company had always maintained an open-shop policy and refused to enforce membership in any union, but recognized the right of every man to belong to unions. The only exceptions have been the I.W.W. and the One Big Union. Both of these organizations have always been fought by the Company. By 1916, membership in the Western Federation being practically 100 per cent, the Company recognized this organization's authority to make agreements, and a wage and hour agreement was drawn up and signed by the Company and the local officials of the Union, and ratified and signed by the Head Office of the Union in Denver, Colorado. This agreement was for the duration of the war.

Jan 1, 1936

By T. G. Joseph, E. Lampard

ABSTRACT: Surface mining operations must manage variability from within their operations as well as variability imposed upon them by external forces. A framework to manage both internal and external variability through the continuous review and adjustment of a mine plan during active mining lifetime operation is introduced, to minimize lost production and maintain operational safety. The observational approach of “observe, evaluate, interpret, predict, and adapt” is employed as the backbone of this approach. Although written with a surface mining operation in mind, the framework outlined in this paper would be equally applicable to any mining or processing operation.

Jan 1, 2011

By S. Banisi, A. Haji-Zadeh, A. R. Hasankhoei, M. Maleki-Moghaddam

At the concentration plant of the Gol-E-Gohar Iron Ore Company (Iran) three 9m × 2.05m AG (Autogenous) mills (fixed speed) are used in parallel in a dry operation. The test works conducted in a scale down mill with a diameter of 1m indicated that conventionally used "deflector" type liners did not provide efficient environment for grinding. In this research, to improve the grinding efficiency, a new design using low profile end liners incorporating radial ribs of proper height was investigated. In order to determine an appropriate liner design at different operating conditions, a 100cm×10.8cm model mill was used for experimentation. The special design of model mill made it possible to increase the radial ribs height in steps of 6mm up to 18.5mm. The transparent end of the mill enabled accurate trajectory determination by image analysis. The results indicated that the new lower height profile deflectors and 15.5mm-height (14.5cm in industrial scale) radial ribs improved the mill performance while avoiding excessive pressure drop across the mill and wear on the liner. The image analysis showed that the use of new liners increased the distribution of coarse particles across the mill cross section from 28% to 35%. A new liner design was proposed by decreasing the number of liners in each slice from 5 to 4 pieces. The thickness of the inner head liners reduced from 45cm to 30cm and the outer deflector liners replaced by radial ribs. The distance between the feed and discharge inner head liners increased from the original 115cm to 145cm which increased the effective length of the mill by 26%. The new design reduced the weight and volume of end liners by 9% and 23%, respectively. It was predicted that the new liners design increases the mill throughput by 10% and reduces the metal consumption by 20%.

Jan 1, 2016

By A. S. Bayne

WITH the great increase in the use of power-driven machinery in industry, and consequent large-scale operations, the hazards to which , workmen are exposed have become much more numerous than at the beginning of the century. This is especially noticeable in mining. In the past thirty years or so, improvements in methods of excavation and metallurgy have made possible the exploitation of deposits which would have failed to make ore in previous years. This improvement, together with the in-creased use of machinery, has facilitated the mining of tremendously greater tonnages with a marked decrease in unit cost of production. This 'speed up' in mining creates numerous problems demanding close attention of operators and necessitates careful prep;tratory planning, as well as diligent supervision of actual operations. Underground openings increase in size so fast, and all phases of mining, mucking, and transportation proceed at such a rate, that a short period of reduced vigilance on the part of operators . results in disaster, both from the standpoint of safety and economies. Happily, the challenge of increased hazards has been successfully met by a general application of the slogan 'Safety First'. Today, we have large manufacturing concerns devoted entirely to the development and production of safety equipment for the protection of workmen in various branches of industry. Machinery manufacturers, in co-operation with their mining customers, have included the best possible in foolproof devices in the manufacture of hoists, compressors, boilers, electric motors, and equipment of all kinds. Mining companies and private individuals spend thousands of dollars and devote a great deal of time to research with the single object of preventing accidents and combating miners? diseases. Governments throughout the world have written regulations into their statures for the protection of miners and operators. Staffs are appointed to enforce these laws and investigate accidents to ascertain means of preventing them for the future benefit of the industry.

Jan 1, 1938

By G. A. Young

THE Geological Survey was created in 1842 to aid the development of Canada's mineral resources. Although the institution has been in existence for nearly 100 years and has accomplished an immense amount of work, the need for its services remains as great as ever and, indeed, it is difficult to imagine a time when the country will no longer require a Geological Survey. This is so because of the tremendous effort required to make an adequate geological examination of so large an area as is embraced by Canada and partly because what today may seem an adequate geological examination proves, later on, to be inadequate. The ultimate objective of the Geological Survey is to complete the study of all phases of the geology of Canada, that is, to determine how and when the physical features originated, how and when the soils and other unconsolidated deposits were formed, and how and when the solid rocks and associated deposits were produced and assumed their present conditions. When the study has been completed, any only then, will it be possible to make a reliable estimate of the country's mineral resources. This appraisal embraces more than determining the value of already discovered deposits: it also involves attempting to establish what kinds of undiscovered deposits may be present and where they may occur. The estimating of the potential mineral wealth can be clone only after the geology of the country is known. Not until then will it be possible to forecast what types of valued deposits may occur in a district and what types will almost certainly be lacking. A thorough knowledge of the geology of the country is desirable not only to permit estimating the potential mineral resources but also as an aid in locating and developing mineral deposits whether these are of the nature of a bed of limestone, a seam of coal, a reservoir of petroleum, a vein, an irregular body of sulphides, or any other type of deposit.

Jan 1, 1940

By Pierre Sauvé, Alex Makila

"The Camflo stock of porphyritic quartz syenite is an irregular pipe-like body 200 metres in diameter injected along the axial plane of an E-W trending F2 fold, near the contact between the. Kewagama and Malartic groups. The stock plunges 55° to the NE, almost parallel to the fold axis. The stock, exhibiting pervasive, weak cataclasis with numerous, locally auriferous quartz veinlets, is cut by minor faults striking WNW and dipping about 45°NE.Two types of gold ore are distinguished at Camflo: ""porphyry"" ore and ""fault zone"" ore. ""Porphyry"" ore, accounting for 90% of the gold produced, forms wide zones within the stock. The zones are irregular in shape but tend to be oriented E-W in plan view (on a horizontal plane) and are elongated paraliel to the plunge of the stock. These zones are more abundant in the northern part of the stock. Differences between ore and barren porphyry are not obvious. ""Fault zone"" ore occurs outside the stock along minor faults, particularly in differentiated sills offer rodiorite and felsic granophyre. Gold grade is roughly proportional to the pyrite content which in turns depends in part on the original magnetite content of the host rock. Although both types of ore show some correlation between Au and S, the Au/S ratio is considerably higher in porphyry ore.The bulk of the gold is in quartz syenite and in felsic granophyre, the most brittle lithologies at the mine. Presumably, the vertically continuous, pipe-like stock, made up of shattered rock, provided the main channelway for the ascending mineralizing solutions."

Jan 1, 1990

By M. Yamine, R. J. Ring, D. J. Waters

"An experimental program has been carried out by the Australian Atomic Energy Commission to compare the effectiveness of Caro's acid as an alternative oxidant to pyrolusite in the leaching of uranium ores from the Alligator Rivers region of northern Australia. Batch leaching tests on Ranger, Nabarlek, Koongarra and Jabiluka ores showed that uranium extraction was unaffected by choice of oxidant, but that Caro's acid reduced acid requirements by 15 - 25%. Lime requirements for neutralization of tailings liquors were reduced by 20 - 30%.The batch studies were extended to a four-stage continuous leaching circuit with a capacity of 400 gore h-I. Comparative leaching tests confirmed the reagent savings obtained in the batch tests. Following these encouraging laboratory results, lnterox Chemicals Pty Ltd carried out plant trials using Caro's acid. Reagent savings in the mill were similar to, or better than, those obtained in laboratory test work. The trials also established that Caro's acid has a number of operational advantages over pyrolusite.IntroductionUranium is most commonly extracted from its ores by leaching in sulphuric acid. Simple hexavalent uranium oxides and compounds are readily soluble but uranium in the tetravalent form is insoluble and must be oxidized for dissolution to occur. The most commonly used oxidants have been sodium chlorate and manganese dioxide. They act indirectly by maintaining iron as the ferric ion which oxidizes uranium by a surface electro- chemical reaction. An Fe3+ concentration of about 1 - 2 g L-I is usually considered adequate for the effective dissolution of uraninite(1)."

Jan 1, 1984

By Rodrigo Serna-Guerrero, Ted Nuorivaara

"As the demand of raw materials increases in a global scale due to demographic and economical changes, it is necessary to find technological solutions that improve current production processes in an efficient and sustainable manner. The main objective of this preliminary study is to evaluate the properties of foam produced with a cellulose-based molecule as an alterative to commercial frothing agents in flotation operations. There are two potential advantages identified with the use of cellulose-based additives for the proposed application: i) these chemicals can be produced from sustainable sources (i.e., non-edible crops), and ii) cellulose can be functionalized with chemical groups, in order to rationally modify its behaviour. In previous studies dealing with foam stabilization, it has been proposed that some functionalized cellulose species present a self-assembly mechanism at gas-liquid interfaces. Unlike typical surfactant-based frothers, cellulose molecules form networks around the bubbles that act as protective layers to the mechanical stress and to the occurrence of ionic species. This work studied the properties of foams produced in the presence of a partially hydroxylated cellulose molecule (i.e., hydroxypropyl methyl cellulose; HPMC) under various concentrations in a laboratory-scale column. A comparison with a commercial surfactant frother (i.e., Nasfroth 240) is presented, and a rationalization of the behaviour of HPMC in terms of foam properties (i.e., surface tension, bubble size, foam depth) is proposed. INTRODUCTIONThe search for green alternatives to chemicals produced from non-renewable sources has become a topic of major relevance in industry (Choi et al., 2015). As a chemical consuming industry, the mining sector faces now the challenge of adopting new processing technologies and strategies in order to achieve the future demands of sustainability. Evidently, a move towards green chemistry can only take place by identifying substitute molecules offering potential advantages in terms of recovery and grade."

Jan 1, 2016

By J. F. Adams, V. G. Papangelakis

Chemical modelling is becoming increasingly useful in the development, analysis, design, and control of hydrometallurgical processes. The paper presents the development of reliable databases for chemical modelling of selected hydrometallurgical systems using state-of-the-art software, such as OLI. The modelling strategies are also demonstrated. The high pressure acid leaching (HP AL) of laterites, oxygen solubility in the oxidative leaching process of zinc sulfide, gypsum solubility and lead chemistry in mixed sulfate-chloride solutions are presented as case studies. This on-going work attempts to bridge the gap between theoretical research and industry needs. Computational Analysis in Hydrometallurgy 35th Annual Hydrometallurgy Meeting held in conjunction with the 44th Annual Conference of Metallurgists ofCIM Calgary, Alberta, Canada Edited by

Jan 1, 2005

By B. K. Bhattacharyya, Morley. L. W.

"The primary purpose of conducting aeromagnetic surveys in mineral areas, and interpreting the data thus obtained, is to aid in the extrapolation of the geology from known to unknown areas-both in a horizontal and vertical direction. This paper describes one of the steps in the process of interpretation which has, in the past, been neglected-that of mathematically or quantitatively treating the data in two-dimensional map form. For this, several techniques are available.These techniques determine the downward and up-ward continuation fields, the second vertical derivatives and the fields reduced to the pole from the total magnetic field data. Second vertical derivatives and downward continuation fields increase the resolution and sharpness in the observed magnetic anomalies and tend to outline the surface traces of causative bodies with a reasonable amount of success in most cases. The 'reduction to the pole' is a mathematical process of calculating the field at the north pole from the observed field so that the un-desirable effects of the dip and declination of the earth's field and of rock magnetization are eliminated.New and accurate means of carrying out these calculations have been developed by the Geological Survey of Canada. In this paper are also presented the results of a method for obtaining the symbol and numerical map of the processed data with the help of the printer associated with the computer. The tedious work of digitizing magnetic field values in a map can be speeded up by the use of a semi-automatic coordinatograph, with the aid of which field values can be accurately transferred to punched cards."

Jan 1, 1966

By William G. Pariseau

"This contribution describes linkage of stress concentration at the face of tabular excavations, for example, longwall coal mine panels, at a meter scale to surface subsidence at a kilometer scale. Joints are considered according to orientation and spacing at an intermediate scale. A new dual-node, dual-mesh technique based on first principles uses a multi-scale technique that allows for computing whole mine surface subsidence while also allowing for computational details of stress, strain and displacement about main entries and pillars, panel entries, and bleeder entries. The technique is implemented in a conventional continuous Galerkin finite element program that has been in use for many years.The advantage of the dual-node, dual-mesh technique is the capability to do a whole mine analysis that takes into account interaction between all sections of a mine where stress transfer over long distances is often the rule rather than the exception while at the same time allowing for details of stress concentration at working faces where caving is initiated and subsidence begins. The technique, outlined recently during ARMA 2014 (Pariseau, 2014), is applied to an underground coal mine in central Utah where mines are developed from outcrops in steep canyon walls. Meshes contain over 10 million, three-dimensional nodes; runtimes are typically overnight, as a practical matter. Results compare favorably with mine subsidence measurements made over a period of several years and show the capability of this new technique to provide useful design guidance for tabular deposits such as underground coal mines. The role of variability or uncertainty in strata properties is illustrated in element safety factor distributions about development, bleeder and main entries and pillars. Such details are new in this contribution. Energy tracking for mine-induced seismicity is also new. Results show a high correlation between number of events and failed elements and suggest a simple index to mine induced seismicity."

Jan 1, 2015

By B. Arlyuk

The complex system has been developed for long-term assessment of world prices and sale volume of primary aluminium when using the analytical model of the market and market supply forecasts as well as economy development in the Western countries characterized by the industrial production indices as correct data of Western World aluminium consumption are absent, The important part of this system is the model developed for forecasting the degree of capacities utilization of smelters and refineries depending on the price level, The model contains a statistic part corresponding to the capacities distribution by the production cost, and a dynamic part determining the deviation from the static depending on the price variation dynamics, The developed complex system has been identified by the actual data of the world prices of smelter grade alumina and primary aluminium, conservation and reactivation of refineries and smelters in the Western countries within the period from 1992 to 2003. The system was used for primary aluminium and alumina price forecasts till 2020.

Jan 1, 2004

By G. M. Scamans

In the past ten years there has been considerable penetration of aluminum automotive body sheet (ABS) into automotive structures. The exponential increase in demand is resulting in major investments in heat treatment and finishing capacity across the globe. Line speed and tonnage throughput is limited by the continuous heat treatment (CHT) floater furnace rather than the cleaning and pretreatment section where electrolytic treatments that offer higher line speeds should come into favour and roll coating of pretreatment should predominate. The capacity limiting surface texturing pass will either be eliminated or moved to the finishing line or a dedicated mill. The key to making aluminum both embedded carbon and cost competitive with steel for more and more affordable classes of vehicles lies in recycling of both prompt scrap and, in the longer term, end of life vehicle scrap. For the first time scrap separation technology is available that can compete effectively with hand sorting and can sort aluminum shredded vehicle scrap into wrought and cast alloys and then into individual alloy groups. The challenge is to use more end of life scrap in alloy formulation whilst at the same time extending the property range in terms of both strength and formability.

Jan 1, 2015