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By R. E. Dye

IF gold mining is to assume, or it might be better said to resume, a place of ' importance in the national economy of this country following the present war, then one must accept the thesis that gold will maintain the place it has for many generations held in the minds of men as a substantial and lasting emblem of material wealth-a metal in exchange for which men have always been ready to give up the possession of their worldly goods. The thought bas been advanced by some that gold is not necessary as a basis for exchange, that it has no real value anyway and, therefore, the world would wake up some morning to find that no one wanted gold and that, over night, its possession bad in some way ceased to be desired. Holding an equally extreme view there are those who advance the idea that, following the war, gold will in some mysterious way enjoy a fantastic increase in value. Neither of these extreme views can be successfully supported. To presume that by legislation or by general agreement gold would be or could be, over night, dethroned to the position of common stone is wholly beyond the realm of any possibility. The thought that this could come to pass is advanced by, and is attractive to, only those peoples who do not have gold and do r:ot have the means of producing it. To believe that the fundamental value of gold will suddenly change is likewise fantastic. I refer to the fundamental value, not the dollar price, of gold, for it cannot be denied that, with the colossal war expenditures now being made and with the huge national debts which are being piled up, there is a possibility, indeed per-haps a likelihood, that the dollar price .of gold may be revised upward. For the purpose of this discussion, however, that possibility is irrelevant and need not be considered.

Jan 1, 1943

By M. Azzaz

In this paper, we report on new mechanical tests, at high temperatures, performed with a supposed better aluminium nitride (A1N) material, containing fewer oxygen. Our purpose was twofold: (i) check whether creep resistance is modified and hopefully enhanced and (ii) determine the elementary mechanisms controlling plastic deformation through transmission electron microscopy (TEM) observations of deformed samples up 10% strain in compression at elevated temperatures (1823-1923 K) under constant stress in the range 150¬250 MPa. Stationary rates are lower by an order magnitude than those previously measured in MN with higher oxygen content. All dislocations imaged by TEM look undissociated, which clearly relates the formerly observed wide dissociation to oxygen in excess.

Jan 1, 2004

By Fathi Habashi

Teaching mining, metallurgy, and geology preceded that of the other engineering disciplines. The first School of Mines was founded in 1756 in Potosi (Fig. 1) in New Spain (now Bolivia), 38 years before the first Polytechnic School (École Polytechnique) was founded in Paris. The schools of mines were also pioneers in the teaching of chem- istry. The teaching staff at these schools cre- ated the basic literature on metallurgy, mining, and geology. They analyzed and dis- covered numerous minerals and discovered the metals tungsten, beryllium, chromium, uranium, zirconium, vanadium, indium, and germanium. The history of some of the first schools is given together with biographies of some of their distinguished teaching staff.

Nov 1, 1997

By Geoffrey C. Streeton

A continual objective of mine operations is to reduce ground control costs without compromising the overall safety or performance of the installed ground support. Any change in the ground support regime must not result in a less secure or safe workplace. The due diligence required to implement a change in rockbolting practice is extensive, particularly when the new bolting system has not been used at any other mining operation. Factors such as yield, shear strength and embedment strength must all be investigated to gain an understanding of how the rockbolt can be expected to perform. This paper also discusses the substantial cost reductions and efficiency gains which can be achieved through the introduction of the Jumbolt rockbolt.

May 1, 2001

By B. Arsenault

Aluminum coatings can provide galvanic cathodic protection for several metals and alloys, In order to be a suitable protective solution on structural components, the mechanical integrity of the component must be preserved, In particular, fatigue properties are a challenge for thermal-spray protective coatings on mechanical structures, To address the issue of the fatigue integrity of 7075 aluminum alloy with an arc-sprayed protective coating, different surface preparations prior to arc spraying were considered, In the present work, a feasibility study was performed using laser ablation as a surface-preparation technique before or during arc spraying of coatings, This was collaborative effort between the LERMPS laboratory in France, the National Research Council Canada and the Royal Military College of Canada, Both fatigue and adhesive properties of aluminum coatings were evaluated in relation to substrate-surface-preparation techniques including laser ablation (Protal® process), grit blasting and shot peening. Results indicate that a combination of key conditions, including the use of nitrogen as the arc spray gas, shot peening, and proper laser energy density for ablation, provide high fatigue resistance of metallic coated 7075 alloy substrates. Specimens prepared under these conditions show a similar fatigue resistance to uncoated substrates.

Jan 1, 2005

SOME months ago a Committee on Deep-level Mining was appointed [by the Government of the Union of South Africa] to consider the possibility of gold mining being carried on at a depth below 8,500 feet. The Committee consisted of Sir Robert Kotze (Chairman) , Mr. H. S. H. Donald (Government Mining Engineer), and Mr. H. R. Hill. The Committee has now made a report which was tabled in the House of Assembly on March 1st. The Committee reported that the tonnage of ore locked up in the deep level areas of the Central Witwatersrand is enormous, and in the 30 miles between Roodepoort and the East Rand Proprietory Mines has a value of about £200,000,000. The Committee says that, with good ventilation, the present system of wet mining, possibly with some modification and with the aid of refrigeration, may be carried to 10,000 feet, but that greater depths will require the adoption of dry mining. "A vigorous campaign of practical experiment into the possibility of dry mining should be initiated, and the Committee recommends to the Government the appointment of a committee of experts, consisting of representatives of the mining industry, the Mines Department, and the medical profession, with the Government Mining Engineer as chairman. The Committee suggests the provision of £30,000 for the first year for the investigations and experiments contemplated, which could best be carried out by an organization which might be styled 'The Rand Mining Research Institute' and constituted somewhat on the Jines of the South African Institute for Medical Research" . The Committee suggests that this committee of experts should arrange for experiments to be made with dry mining in one of the deepest mines, and investigate ventilation, refrigeration, support of workings, and the physiological problems connected with mining. "We emphasize the necessity of treating this whole question as one of importance and urgency. The investigations should be prosecuted with the utmost vigour and should not be delayed at any time for want of funds or for any other reason. If they are not done thoroughly and quickly, the whole scheme might just as well be left severely alone.

Jan 1, 1945

By K. H. March

In the present very highly competitive condition of the bituminous coal business, it is becoming increasingly apparent that coal mines which do not lend themselves to efficient mechanization cannot long survive. It would seem that those mining operations best fitted to survive the struggle for existence are burdened with the considerable capital and maintenance cast of carefully selected mechanical and electrical mining equipment. The ever changing conditions of coal mine operations require equipment which is adaptable to a variety of uses; and investigation of the mechanical and electrical equipment in most mines will show that the operating duty of much of this equipment is considerably different from that duty for which it was originally selected. And it would appear that one of the essential qualifications for a successful mine management is a marked ability to get satisfactory operating results from equipment which has been transferred from some other operation, rebuilt, rearranged, or in some way adapted to the job at hand. As a striking example of such mechanical ingenuity, many of us recall that the first longwall jigging conveyor used in Nova Scotia was built in Sydney Mines from odds and ends in the scrap pile at a total cost of less than $50.

Jan 1, 1930

By M. Mirnezami, J. A. Finch

The McGill component of the consortium contributed detailed examination of the electrokinetic properties of the constituent minerals, primarily pentlandite and serpentine. Mineral specimens were derived from an ore sample; mineralogical examination showed the serpentine was predominantly clinochrysotile, a fibrous mineral responsible for much of the flotation separation problem. The study included design of a novel sedimentation potential measuring device to classify the surface charge of the ore and electrophoresis measurements on single and mixed minerals which progressively approached flotation conditions. The sedimentation potential measurements provided a general association between surface charge and the visual state of aggregation as a function of pH. The electrophoresis experiments started with single minerals in a background of indifferent electrolyte and progressed to mixed minerals in a background of supernatant derived from an ore sample. The single mineral tests supported the suspected electrostatic interaction, i.e., hetero-coagulation, at flotation pH 9-10. The mixed mineral tests demonstrated this interaction and also revealed hetero-coagulation with Mg(OH)2 precipitates, derived from the supernatant. This interpretation was confirmed by optical and electron beam imaging. A series of agents, CMC, polyphosphate, soda ash, EDTA, were examined to disperse the system. To accommodate the small mass of single mineral available a novel turbidity measurement using a UV/Vis spectrophotometer was introduced. Selected conditions were used in contact angle and small-scale flotation tests.

Jan 1, 2011

By K. J. Aglias, M. Jeffery, J. V. Simmons, J. A. Johnston, S. G. Fityus

"Shales and mudrocks undergo weathering in the near-surface geological environment, and degradation when directly exposed at the surface. Despite having superficially similar appearances, many shales have very different degradation behaviours. For example, some shales break down readily upon exposure whilst others remain more or less intact. Further, for those shales which break down, the style of degradation can vary greatly. A phenomenon is described where fresh shale blocks that are exposed at the surface undergo rapid breakdown to a fragmented texture which then persists for relatively long times, without further breakdown to finer soil particles. This is illustrated for some coal mine waste rocks. Furthermore, this metastable fragmented texture seems to be particular to each particular type of shale. The paper presents a conceptual model for this physical breakdown of shales which accounts for the differences in fragmental texture that are observed. The importance of several factors including strength, permeability and expansive clay content are identified for their contribution to the degradation behaviour of different shales.INTRODUCTIONShales and MudrocksThe term shale is applied widely to a class of mudrocks having a range of distinctive but gradational appearances and mechanical behaviours. Mudrocks are sedimentary rocks primarily composed of silt and clay sized particles (Tucker 1982). Mudrocks form in low to very low energy environments such as flood plains, lakes and deltaic environments, where the finest detrital particles are able to settle out of suspension (Reeves et al., 2006; Stow, 2005; Tucker, 2001).Unlike coarser siliciclastic sedimentary rocks, mudrocks do not present with a wide variety of sedimentary structures and textures. The most common texture is a preferred orientation of clays and micas parallel to the bedding plane. This textural component is related to the property of fissility or the ability for such textured mudrocks to split along smooth planes that are parallel to the bedding. Another common structure is lamination, formed by variations of grain sizes and types during deposition, Massive texture describes the situation where no sedimentary structures or textures are apparent (Boggs Jr., 2009; Tucker, 2001). The term shale varies between sources and contexts, with Reeves et al. (2006) stating that a shale is a fissile mudrock, where “fissility is a property that has developed at a certain stage of weathering”."

Jan 1, 2015

By J. Petit, P. Girard, A-M. Gilbert, D. Faucher

L&apos;annee 2000 a été une année stratégique et significative pour l&apos; Aluminerie de Bécancour dans la réduction des gaz a effets de serre. L&apos; équipe s&apos; etait donne comme defi un jour d&apos;arriver a l&apos;objectif de zero effet d&apos;anode dans les sa11es de cuve (720 cuves au total). Le cha11enge s&apos;averait tres ambitieux car la fa<;on d&apos;alimenter une cuve d&apos;electrolyse pour obtenir son maximum de rendement faraday est de travailler le plus pres possible de l&apos;effet d&apos;anode pour eviter l&apos;embourbement de ce11es-ci. Ceci signifie que techniquement nous a11ons en moyenne, quotidiennement, 12500 fois pres de l&apos;effet d&apos;anode sur !&apos;ensemble de nos 720 cuves qui produisent aujourd&apos;hui environ 405 000 tonnes d&apos;aluminium liquide annuellement. Des 695 kg equivalent en C02 par tonne d&apos;aluminium produite en moyenne annue11ement, de 1990 a 2000, nous en sommes rendus ace jour a environ 35 kg equivalent en C02 par tonne produite. Nous sommes pres d&apos; atteindre notre objectif mais les demiers gains sont plus difficiles a atteindre. Les strategies d&apos;automatisme et d&apos;informatique, incluant l&apos;aspect de !&apos;implication humaine sur les bonnes pratiques de travail sur les cuves d&apos;electrolyse, sont les cles de ces resultats.

Jan 1, 2006

By Silvio E. Kruger

Real time measurement of wear and corrosion provides crucial information needed to determine an optimal schedule for corrective maintenance and is a powerful tool to maximise equipment availability and reliability. It also leads to savings from optimized spare parts handling and helps to avoid costs of accidents and their negative impact on safety and the environment. This paper presents the technology of ?painted-on? ultrasonic transducers that can be integrated to structures and accurately measure the remaining thickness and therefore determine wear or corrosion losses. These transducers have a small footprint, a performance comparable to other commercially available ultrasonic transducers and can sustain temperatures as high as 400ºC. The application of this technology to mining equipments and its potential benefits are discussed.

Aug 1, 2013

By A. Vervoort

The concepts of geostatistics are commonly difficult to understand for students, even for those with a strong mathematical background. A main problem is certainly the link between the variation of the parameter value in space or time, and the calculated experimental semivariogram as a function of the interdistance, but over the entire area. Another problem is to differentiate between directional and omnidirectional semivariograms and the way they have to be interpreted. Furthermore first time users of geostatistics often do not want to struggle through different books with the whole geostatistical background before using it. Too often this leads to using geostatistics as a black box with all the risks linked to it. That is the main reason that we developed some interactive tools based on the free public domain software R. We aim by developing three different modules to assist individual first time users, but also regular students and teachers to get a feeling of the importance of the various aspects in conducting a good geostatistical study. The modules show directly e.g. the impact of deleting, moving or adding data points, of changing parameters of the semivariogram model and of the geometrical parameters during kriging. The first module allows making the link between the variation of the parameter values in one direction and the calculated experimental semivariogram, and this for different given datasets. The second module covers two dimensional datasets and apart from calculating the semivariogram values, models can be fitted to the calculated data. A distinction can be made between omni-directional and directional semivariograms, including the effect of the tolerance on the angle and lag-distance. The third module focuses on ordinary kriging of point values in two dimensions. The aim of the interactive tools developed is limited to educational purposes only, i.e. to visualize some basic concepts for different pre-selected types of spatial variation. They do not intend to do a geostatistical study on a certain dataset (for this purpose there exists already a broad spectrum of good software packages). The original intention of developing the three modules was aimed at users with no or a limited amount of geostatistical experience. However, these modules seem also very useful to remain critical for experienced users. One should never forget that in a real application one does not have a complete view of the phenomenon studied. The geostatistical interactive modules can be accessed through: www.bwk.kuleuven.be/geostatistics . We compiled a manual to facilitate the use of the modules and to guide the user we formulated several questions to be solved for each module.

Aug 1, 2013

By J. Palarski

Hard coal, mined in Silesia Region as well as in the eastern part of Poland, is a key national resource. In Polish underground coal industry, modern mining technologies have been successfully tested and used in the last 50 years. More than 98% of the coal produced underground is extracted by longwall mining method. Current underground coal mining expands into increasing depths. The use of conventional coal extraction methods ? room and pillar and longwall with caving - is becoming increasingly difficult. The coal mining is modifying existing methods and is testing innovative technologies. Backfill is an important component of modern underground mining operations. In Polish underground mines, backfill is recognized as an integral component for extraction of coal from greater depths in a densely populated environment. The modifying and innovative methods require the use of backfill or grouting of caving to provide structural support in underground excavations and to ensure that the mining operations are safe. Depending on the geological structure, mining conditions and environmental requirements there are several variations of longwall methods used in underground coal mining in Poland, in particular: longwall with caving, longwall with backfill, longwall with grouting of caving area. This paper will discuss the different components of an effective longwall production and filling process of caving area. The paper will give a overview of the current application of backfill technology, focusing on Polish coal mining operations. This paper will also briefly describe how backfill contributes to an innovative method ? underground coal gasification. The paper discusses specific requirements for fill materials and the technology of backfilling for underground coal gasification (UCG) operations and problems of implementation and correlation of backfill parameters with other processes that occur during thermal processing of coal.

Aug 1, 2013

By A. J. Paul Laprairie

"ADVANCE planning of mining methods, from the first development openings to stope layout and pillar recovery, has long been accepted as a normal method of operating a mine. Recently, mine managers have become increasingly aware that advance planning of cost and accounting controls can also be considered a normal method of operation. The use of such controls is wide-spread in manufacturing industries. In mining, the gold mines of South Africa have pioneered, with marked success, in this field and have been closely associated with most of the research and field work in accounting control. Canadian mine managers are also beginning to realize the advantages of using planned costs. The control procedures which subsequently have been introduced at various mines have come to be known by such names as ""Responsibility Costing"" or Budgetary Control"".Budgetary control, the term used in this paper, is based on the concept of decentralized authority with centralized control. ;The control is achieved by measuring results against yardsticks which are in the form of budgets or standards. Bud-gets are made for the future activities of each possible operation as planned by the department head, and attention is directed to variations from this plan. Furthermore, the control process charges to each operation only those costs which are incurred directly for that operation, and which can be controlled by the person in charge. Thus, budgetary control relates results to the officials responsible for those results. Expenditures are analyzed according to the organizational structure of the mine and the people who run it, and not according to production processes."

Jan 1, 1960

By M. N. Pons, F. Ferrari, V. Houzelot, B. Laubie, A. Bani, Université de Lorraine-CNRS LRGP

"More than 400 plants in the world are able to accumulate nickel in their aerial parts at concentrations higher than 10 g per kg of dry biomass. Then, nickel (Ni) can be recovered from the biomass of these hyperaccumulator plants. Agromining is a chain consisting in growing such plants and recovering metal and has been developed thanks to the combined know-how of agronomy and hydrometallurgy. Plants can be grown on serpentine soils, containing rather high concentrations of Ni, on sterile heaps or on contaminated soils. This crop enables us to extract Ni from secondary resources, and to improve soil quality by lowering its metal content. For example, Alyssum murale can be grown at the field scale in the Balkans, at yields corresponding to 110 kg Ni per hectare.Hydrometallurgical processes have been designed from the lab scale to the pilot scale to produce nickel salts: ANSH (ammonium and nickel sulphate hexahydrate), nickel sulphate, acetate, etc. and so on. These salts are used for surface treatment and in the paint and chemical industry. Ni salts are prepared from ashes, after plant calcination. Processes are based on the conventional methods of hydrometallurgy: acid leaching followed by different precipitation steps. These processes will be presented, as well as the pilot scale design. A life cycle assessment has been performed and clearly shows the environmental interest of this approach as a potential part of an anti-erosion strategy. An economic assessment has proved process feasibility and the final step is the launching of a start-up. At the moment, the approach is widened to other metals (cadmium, cobalt) and rare earth elements (REEs)."

Jan 1, 2016

By John Lamb

"The French Mine (formerly the Oregon) is 4 miles by road south of the Nickel Plate Mine. It lies on the steep eastern slope of the Similkameen River valley at elevation 4,000 feet, between Cahill and Winters Creeks.The property was discovered in .1901 and bought 4 years later by Messrs. French and Deardorf. It was developed in a modest way by the owners and by several companies until 1947, without success. The spectacular showings of bornite and chalcopyrite in the outcrop drew attention to its possibilities for copper rather than gold. Diamond drilling by the owners in 1947 yielded several high-grade gold intersections and created new interest. In 1949 the property was purchased by Kelowna Mines Hedley Limited. Exploration drilling and geological mapping outlined sufficient ore to commence production in 1950. Except for a few months each winter the operation has been continuous, and to the end of 1954 had produced almost 30,000 tons of high grade ore. The ore is crushed at the mine and hauled 8 miles by truck to the Company mill at Hedley, where it is treated together with the ore from Nickel Plate.Regional GeologyThe country rock consists of brown tuff, flows, limestone, and cherty formations belonging to the Nicola group (Rice 1947) of Triassic age. West of and just below the mine is a large mass of granodiorite which is part of the same body that underlies Nickel Plate Mountain. Bedding attitudes in the mine area are locally complicated, but dips are generally less than 45 degrees. To the south and below the mine the beds stand almost vertical, continuing downward with this attitude for 2,000 feet to Winters Creek. The main granodiorite contact is also steep, conforming to the sedimentary formations, whereas northward towards Nickel Plate it dips gently to the northwest, slightly flattter than the thick westerly dipping pile of sediments above it. The interpretation of this structure by Billingsley (1936) is that the French mine lies near the crest of the large northeasterly trending asymmetrical anticline which contains in its gently dipping western limb the Nickel Plate orebodies. The granodiorite body conforming roughly to this shape seems to occupy the core of the anticline. Sill-like prongs of granodiorite extend upward to the east from the main mass, outcropping over wide areas at the head of Winters Creek (Figure 1). There is a possibility that overthrusting from the west, similar to that on Nickel Plate Mountain, occurs not far below the French mine.An interesting feature of the granodiorite-sediment contact is that where it dips gently westward no alteration exists in the sediments, but where it has a steep front pronounced heat effects are indicated by the presence of a thousand-foot-wide zone of reddish garnet skarn."

Jan 1, 1949

By A. Bouajila1

Minerals processing organisations will be more and more under intense competitive pressure. Major changes are being experienced with intense respect to resources, processes, production strategies and markets. As result of international competition, only the most productive and cost-effective operations will survive. That is why operators in the minerals industry have always aimed to obtain better performance from their processes along the mineral extraction cycle starting from exploration up to the smelting step if any. A principal ingredient and perhaps the most important one in the process of evolution toward improved productivity is the achievement and implementation of an error-free production synonym of an ignorance-free operation. This is, at the same time, a guarantee for quality, a minimising factor for waste materials production, handling and disposal, and a maximising factor for labour utilisation. The notion of ?error or ignorance-free? -usually identified as a ?made in Japan? manufacturing mythology, will sound, at first impression, like a pious ideal, to be striven for but impossible to attain. Nevertheless, the introduction of measurement and detection technology in the minerals industry along the last century should benefit from the today?s sensors and control systems that explosively expanded beyond their traditional production base into far-ranging commercial ventures. The fastness and spread of those technologies will play an important role in the survival of innovative plants. Their role in information assimilation, and control of operations to maintain an error-free production environment, will help many plants to stay effective on their competitive course. In this paper the feasibility of the zero process ignorance concept as applied to the comminution circuits will be discussed and the challenge behind this ambitious move toward improved productivity will be outlined. Examples of pre-competitive R&D projects started at COREM in order to fulfil this prerogative will be presented.

May 1, 2001

Agenda ? Introduction ? Inmet?s Operations and Closed Properties ? Inmet?s SECA Philosophy ? Inmet?s SECA Framework ? The Business Case for TSM ? Inmet?s TSM Reporting ? Inmet?s 2004 TSM Performance ? Opportunities for Improvement ? What Have We Learned From The TSM Process So Far? ? Summary Introduction ? Inmet has evolved into a strong TSM supporter ? Inmet is confident that TSM can be successfully and cost effectively implemented by smaller companies ? Inmet?s reporting on economic, environmental and social performance was raised significantly in our 2003 Annual Report ? a signal our commitment to good performance and improvement in these areas ? Our 2004 Annual Report has been further enhanced with the inclusion of our TSM performance

Apr 1, 2005

By J. Hoover

"IntroductionThis chapter will discuss the operational and maintenance aspects of a heavy media cyclone circuits as applied to coal processing and using magnetite as the media. It deals with heavy media bath separators in terms of types of media, equipment, circuits, media recovery, maintenance, and product handling. It will detail heavy media cyclone operation and supplement the previously described topics.The heavy media cyclone was first developed in the Netherlands by the Dutch State Mines in 1945. A cyclone plant was not built in North America until 1961. Traditionally, heavy media cyclones have been used to treat size fractions between 1lz in. (12 .6 mm) and 35 mesh (0.5 mm). High maintenance related to heavy media bath separators has recently prompted some plants to crush all raw coal to minus 2 in. for treatment in heavy media cyclones.The heavy media bath separators utilize only the force of gravity to make the separation between heavy and light particles. This requires lengthy retention time which can lower capacity and also is inefficient for finer particles. A heavy media cyclone utilizes centrifugal forces which are 20 to 200 times greater than the force of gravity. This means the separation between coal and the impurities occurs very quickly, therefore a low retention time is required allowing cyclones to have high tonnage capacities. Also these greater forces allow better separation for the finer particle sizes.Heavy media cyclones are now widely used to produce both metallurgical and thermal coal. Work is in progress to reduce magnetite consumption, extend wear life, increase tonnage capacity, improve separation efficiency and automatically control these cyclone circuits."

Jan 1, 1989

By A. Dave Mackintosh

Historical closure data has provided a description of the stress distribution patterns occurring around mine openings and enabled the development of a time ? distance plot predicting the location of the stress peak and its migration away from mine openings with time. Data collected from active mining areas during the 1970?s and 1980?s indicated the peak appeared to stabilize approximately 135m (450 ft.) from openings after four years. The region of high load and accompanying poor ground conditions in which the peak was centred was spread over approximately 45m (150 ft.) to 60m (200 ft.). Recent data from new development headings cut adjacent to 25 year old extraction areas suggests load transfer takes place over a much greater distance and time frame than predicted.

May 1, 2001