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As a bubble travels through the pulp region of a flotation cell, it will collect the most hydrophobic particles of an intermediate particle size range, this being the primary source of true flotation selectivity. Despite its role on bubble-particle attachment, however, particle hydrophobicity is still missing a mathematical definition that can be used for plant simulation. In this paper, particle hydrophobicity is defined in terms of the induction time necessary for attachment and then linked to the mass of collector adsorbed per particle. This allows particle hydrophobicity to be written as a function of density of collector adsorption as well as particle size and mineralogy. The model is calibrated from the experimental measurement of the flotation rate constant. Liberation data from an industrial flotation rougher is used for model validation. It is demonstrated that the model can describe a broad experimental dataset by means of a minimal number of parameters. Main industrial application is in simulating the effect of the chemical environment upon plant metallurgical performance.

Jan 1, 2006

By J. Chelsey Dawson

In presenting a thesis on this subject it is advisable to explain a few of the reasons for its seeming incompleteness. World progress has brought us to a position where approximations are not only to be condoned, but regarded as absolute essentials. Production in anticipation of demand is always accompanied by mistakes on the part of the producers. Only through trial and sometimes erring hypotheses may there be evolved the true course and theory upon which the steady triumphant march of world-wide industry depends. The average person likes to have everything placed ?before him in a clear and convincing manner. It is the impossibility of doing this which, in many cases, arises to confound the writer on shales. All that one can do is to present, as lucidly as possible, the known hypotheses' and theories on the subject and leave the reader to study and work out the truth for himself. Many theories have been advanced on the origin of oil-shales ; some may be correct in certain instances and not in others; however, the writer will attempt no decision as to which are and which are not correct, but .will merely point out the relative merits of each. The figures given for reserves of oil and shale in different countries are only approximations and give but a rough idea of the true conditions.

Jan 1, 1925

By J R. M Hutcheson

Advocate Mines Limited came into initial production on June 30, 1963, with an annual capacity in excess of 60,000 tons of high-quality chrysotile asbestos fihres, thus strengthening Canada's position in world production. The history of this development is traced from discovery through initial exploration, financing, orebody delineation and evaluation, pilot-plant production and product evaluation, construction of the plant, construction of deep?-sea shipping facilities, provision for a closed shipping season, and provision for the remoteness and for the lack of services, through to realization of full production capacity. The many unique aspects of the project are given special attention, particularly in the light of the first year of full-capacity operation. The marketing of the products in a highly competitive world market is reviewed, with special emphasis on product evaluation, quality control and the shipping of high-quality products to consumers throughout the world. C ANADA'S newest asbestos producer, Advocate Mines Limited, is located at the north end of the Burlington Peninsula, White Bay District, Newfound-

Jan 1, 1965

By G. E. Agar, W. B. Kipkie, R. A. Tenbergen

"This paper describes the successful pilot plant testing of a flowsheet, developed at Inca Ltd.&apos;s J. Roy Gordon Research Laboratory (JRGRL), for improved separation of the constituent minerals in a bulk copper-nickel concentrate.The flowsheet utilized the fact that xanthate concentration on the mineral surfaces is the most important variable affecting the high lime separation and that reduction of the xanthate concentration could be affected by an oxidative conditioning stage.When the adsorbed xanthate was reduced to a suitably low level, chalcopyrite and pyrrhotite could be floated to leave a high-grade nickel concentrate as the residue. Sodium cyanide was added to the froth product 10 depress pyrrhotite and any remaining pentlandite. The temporary depression of chalcopyrite by the sodium cyanide was overcome by introducing a conditioning step following cyanide addition . The advantages of the flowsheet; improved copper-nickel separation, operation without heating of the pulp, production of both high-grade nickel concentrate (29.5% Ni, .26% Cu) and copper concentrate (<0.5% Ni, 30% Cu) were all realized.IntroductionLaboratory test work undertaken at Inco and described previously(1) has demonstrated the importance of low xanthate concentrations on the mineral surfaces in the copper-nickel separation at the Copper Cliff mill.It was determined that oxidation of the separator feed (a cleaned bulk concentrate, grading about 11% Cu and 11% Ni) to lower the xanthate concentration on the mineral surfaces prior to separation significantly improved the quality of the separation (CI 4)*, particularly when no cyanide is used, but also when cyanide is added. As well, it was found that the oxidation permitted a pentlandite-pyrrhotite separation - the oxidation step brought about a decrease in the flotation-rate of pentlandite leaving pyrrhotite and chalcopyrite largely unaffected. Consequently, it was possible to produce a highgrade pentlandite product (30% Ni, 0.3% Cu) at ~83% Ni recovery , as well as a high-grade copper concentrate (0.5% Ni, 30% Cu at -96% Cu recovery)."

Jan 1, 1985

By J. A. C. Ross

Introduction To enlighten those who may be wondering where anyone could find sufficient data to write a paper on underground concrete work, the author would like to explain that, at Copper Mountain, we have found it necessary to line numerous headings with a layer of concrete in order to keep them in a safe and serviceable condition. The majority of these headings are scram drifts and ore-pass raises. This paper will therefore deal, in the main, with the methods of and reasons for placing concrete in these headings. During recent years, radical changes have been made in the methods of mining ore at the Copper Mountain mine. After considerable experimenting, a mining system has been developed making use of diamond drills for primary breaking and transfering such broken ore through scram drifts with slusher hoists. With the advent of scram drifts, it soon became apparent that some substantial means of reinforcement and protection for the scram drifts themselves would be necessary. Since the orebodies in this mine are cut by numerous dykes or faults, and often both, it was anticipated that some means of support would be required where headings necessarily passed through these incompetent zones. Further, as experience was gained, scram drifts were driven into pillars and in close proximity to old workings so as to recover the maximum amount of ore. In such places, the ground is often severely fractured, either as a result of previous mining or from the effect of excessive rock pressures.

Jan 1, 1950

By Peter N. Calder

The orientation of planes of inherent weakness (joints) with reference to an excavation in rock is the critical factor determining stability. The purely frictional 'residual' strength remaining following the breakdown of initial cohesion is the only strength which can be counted on to resist sliding for the long term. A simple method of resolving driving and resisting forces in three dimensions along joint intersections 'undercut' by the excavation is presented. Contrary to the case of slope failure in soils, it is shown how significant changes in the slope angle sometimes have no effect on the degree of stability pre-sent in rock slopes. Wall control by reorientation of the slope, the use of cable bolts and water diversion are briefly discussed.

Jan 1, 1970

By Dale A. Walters

The thermal recovery of bitumen reservoirs by steam assisted gravity drainage (SAGD) is often designed to maximize the operating pressure. In general, the benefits of higher operating pressures are higher steam temperatures that maximize the reduction of oil viscosity, potential permeability enhancement associated with lower effective stress and shear dilation, and a larger pressure window to allow flexible control of the producer. This is especially important for shallow reservoirs where the pressure window for injection and production is smaller. Higher operating pressure can reduce thermal efficiency (due to heat losses), but the other benefits usually compensate. The limitation of the maximum operating pressure is then based on maintaining caprock integrity. Thus, shear and tensile failure mechanisms must be quantified and managed. This paper presents a geomechanical analysis of caprock integrity for SAGD operation. Both analytical and numerical approaches are used to investigate the modes of caprock failure. Main factors in the analysis are the knowledge of the initial stress state and proper representation of the complexity of the geomaterials. Typical initial stress states for northern Alberta are presented showing the potential for low initial minimum total stress and elevated initial shear stress levels. The stress-strain behavior for the sand and caprock materials is discussed focusing on the potential for shear dilation in the sand and shear strength behavior in the caprock. Elasto-plastic constitutive models used to represent the sand and caprock are presented and compared using numerical analysis. The increase in pressure and temperature alter the stress state and disturb the soil matrix. This disturbance results in shear dilation of the sand matrix creating regions of enhanced permeability and porosity. Also, the transfer of stress and strain to the caprock causes dynamic stress changes and, therefore, dynamic behavior of shear and tensile failure conditions. Calculations are presented showing the stress paths associated with SAGD operations, suggesting better design of lab testing programs and the implications for shear dilation in the sand and shear failure in the caprock.

Jun 1, 2012

By M. R. Campbell

"IntroductionON THE LAST DAY of December, 1951, a half-century of steel production was completed in the open hearth department of Dominion Iron & Steel, Limited, in Sydney, Nova Scotia.During that period, almost every known variation of basic steel making practice was used in working out a steel making process which would overcome the difficult metallurgical problems imposed by the use of Cape Breton coal and Wabana ore.This paper is presented as a brief review of these steel making practices, setting forth the fundamental metallurgical factors involved in their success or failure.Establishing the IndustryThe story of steel production at Sydney is closely interwoven with that of coal. The steel industry owes its inception to a desire on the part of the Dominion Coal Company, which was incorporated in 1893, to improve its marketing position by increasing sales of slack coal and providing a year-round demand for its product. Accordingly, the Dominion Iron and Steel Company, Limited, was incorporated on March 30th, 1899, with Mr. H. M. Whitney -who was President of the Dominion Coal Company -as its first President. The new Company was given powers to manufacture and process iron and steel, and to mine all minerals, including coal.A strong inducement to the industry was the bounty offered by the Dominion Government for the production of both iron and steel."

Jan 1, 1952

By Earle J. Klohn

"The design, construction and operation of tailings dams is rapidly becoming a major consideration for most new mining developments, as well as for many existing operations. In North America, under pressure from public opinion, various government agencies have in recent years enacted legislation covering the design, construction and operation of tailings dams. In British Columbia, comprehensive legislation has been passed during the past year (1971). All of these new regulations may be placed into two broad categories: regulations concerning the safety of the dam and appurtenant structures, and regulations concerning the prevention of pollution. Both types of regulation affect the design of the tailings dam facilities. Consequently, they must be considered jointly by the designer. A good tailings dam design must satisfy the basic requirements of safety, pollution control, storage capacity and economy. To achieve this, 'the design must be based on a thorough understanding of both the geotechnical problems involved and the requirements of the mining development. Obviously, this requires close cooperation between the designing geotechnical engineers and the mining operators. This paper outlines the major engineering factors that should be considered in the investigation, design, construct ion and operation of tailings dams. Basic methods of tailings dam construction are reviewed and the advantages and disadvantages of each briefly discussed. Comparisons are made between the design and construction of conventional water supply dams and tailings dams. Examples are presented of some of the problems that may arise during construction and operation of a tailings dam. The paper also explains the need for basic instrumentation of tailings dams and for carrying out simple field tests and measurements during construction and operation. Of prime importance is the downstream monitoring of surface and subsurface seepage flows. These observations are invaluable where contamination of surface and/or subsurface water may become a contentious issue at some future date. Each tailings dam design must be based on a study of the particular requirements of that project. To make a proper evaluation, adequate data must be available concerning a large number of items•, including such things as: topography, hydrology, geology, subsoil properties, seismicity, government regulations, fineness of mill grind, mill water balance, availability of suitable construction materials, volume of water to be stored behind starter dam, downstream development or liability, and many others. The large number of variables involved in such an evaluation often result in the designer considering two or more alternative designs. Selection of the final design, which is usually based on detailed cost analyses of the alternatives, must be made in close consultation with the owner."

Jan 1, 1972

By D. G. F. Hedley, F. Grant

"In 1958, the Ontario Department of Mines appointed a committee to study the accident situation and mining methods used in the uranium mines in the E1liot Lake district. This committee reviewed the existing knowledge on mine design, pillar support and roof spans and came to the conclusion that scientific knowledge had not yet reached the stage of producing rational design procedures which would reduce the dependence on trial-and-error methods. Since that time, the Mining Research Centre has made numerous stress measurements in two mines to define the pre-mining and pillar stresses. A comprehensive series of tests has been done in the laboratory to measure the compressive strength of the rock; a geological survey of the region has been made to evaluate tectonic stresses; and a survey was done on mining conditions with regard to stable and unstable pillar configurations. This information has been used to evaluate pillar design as effected by pillar width and height, depth below surface, extraction and pre-mining stress fields. The resultant design of pillar widths and corresponding extraction as the depth increased is in line with past and present experience in these mines. The information available on roof stability is still insufficient to design stable stope spans with the same degree of confidence; experience and trial-and-error methods are still required."

Jan 1, 1972

By John G. Henning

Unplanned ore dilution has a direct and large influence on the cost of a stope, and ultimately on the profitability of a mining operation. This paper presents results of a study on the influence of a variety of factors on ore dilution in a blasthole stoping environment. A series of 3-D numerical models were developed and analyzed to examine the effect of mining depth, stope geometry and stope setting within the orezone extraction sequence. To quantify modelled ore dilution from the three-dimensional simulations, the ore Dilution Density (DD) is a term introduced in this study to denote potential hanging-wall overbreak. It was found that hanging-wall overbreak is not significantly influenced by depth alone, and that stopes with large or small axial ratios are more stable than large rectangular stopes. It was also demonstrated that, in addition to stope dimension, the amount of unplanned dilution differed according to stope type. Five stope types were identified, based on their position within a tabular blasthole mining sequence. The methodology presented in this paper can be adopted to develop mine-specific design tools for the estimation of ore dilution associated with a proposed mine design. This can prove extremely helpful in the process of underground mine planning and optimization.

May 1, 2007

By Roland B. Hoag, Roger G. Webber

Sulphate concentration in groundwater is a good measure of the extent of oxidation of sulphides, provided that sulphide minerals are the primary source of the sulphate. A study was conducted near the Eustis Mine in Quebec to determine where and how the sulphate in groundwaters originated. Atmospheric precipitation is the only source of sulphate other than oxidation of sulphides, and in this study area it is equal to 0.01,. millimole per litre. The oxidation of sulphides can be divided into subsurface oxidation (mainly inorganic processes) and surface oxidation (including both organic and inorganic processes) . The maximum sulphate concentration due to subsurface oxidation of sulphides depends on the solubility of 0 2 in water and is 0.25 millimole per litre. Surface oxidation is, therefore, responsible for any amount greater than atmospheric plus subsurface contributions (0.29 millimole per litre). Surface inorganic oxidation occurs in waters with a pH greater than 15 and is controlled by the kinetics of the oxidation processes. Organic (bacterial) surface oxidation is dominant only in acid (pH< 1.5) waters. The bacterial action accelerates the oxidation of sulphides, and large quanttties of sulphate may be introduced into solution.

Jan 1, 1976

By B. Tiryaki, M. Ayhan, O. Z. Hekimoglu

"This paper discusses the aspects of tracking cutters related to the computer-aided design of shearer drums. A comprehensive computer analysis of drum dynamic parameters for multi-tracking tool arrangement is not presently available, as the current computer programs mainly consider the aspects of single tracking. Despite the fact that the single-tracking arrangement is recommended for efficient cutting, some major drum manufacturers have been seen to persistently adhere to multi-tracking, probably due to a lack of information. Further studies in this field are believed to contribute greatly to the current understanding of the computer-aided design of shearer drums.A number of laboratory simulation trials and long-term underground investigations were carried out in detail on tracking cutter arrangement, and an equation required for a computer program was derived. The results obtained from computer assessment of dynamic parameters for drums with multi-tracking arrangement were found to be in accordance with those of the underground trials, indicating the validity of the equations. The procedure adopted for the computer appraisal of the shearer drums designed with a multi-tracking concept, as described in this study, is therefore recommended to be considered in the currently employed computer programs."

Jan 1, 2003

By B. Hohenstein, B. McBain, B. de Jong

"The automated fire assay system (Fast In-line Fire Assay or FIFA) has not found acceptance in the Au mining industry as the lower measurable limit of 0.20 ppm did not allow Au tailings to be measured with confidence. The development of arrested cupellation has overcome this hurdle which was a limiting factor in the FIFA 1 process. In the new automated fire assay process, automated sample preparation, fluxing, fusion and separation of a Pb button are essentially similar to the FIFA 1 process, albeit with some improvements. However, the game-changer is the development and incorporation of arrested cupellation into the automated system, now called FIFA 2. The purpose of arrested cupellation is to reduce the 50 g Pb button to a 5 g Pb button by partial cupellation in a specially developed arrested cupellation system thereby concentrating the Au in the Pb by a factor of 10 and in so doing moving them into higher concentration ranges in the mini-button where they can be read on the spark spectrometer. Results show that concentrations down to 0.02 ppm Au in geological materials can now be determined using arrested cupellation in the FIFA 2 process, an order of magnitude improvement over FIFA 1.INTRODUCTION Traditional fire assay for Au has remained virtually unchanged for 3000 years. It has survived for so long because it is accurate, has relatively low detection limits and is relatively inexpensive. However, it is labour intensive, has a long turn-around time (typically at least 7 hours), is environmentally unfriendly and exposes assay operators to potentially unsafe conditions (toxic fumes, toxic dust and extreme heat from furnaces). The NiS collection method is not as effective for the assay of Au as it is for the PGEs. A rapid, accurate, cost-effective method for the determination of Au and the Platinum Group Elements (PGEs) in geological materials would be a tremendous benefit to mining companies. Many of these objectives have been met by the FIFA 1 (Fast In-line Fire Assay) developed some 15 years ago in which automated methods have replaced the manual procedures which are part and parcel of conventional fire assay. However, concentrations below 0.2 ppm have been very difficult to achieve with sufficient reliability."

Jan 1, 2017

By C. Lambert

It has been shown that contacts between host rock and engineered barriers may be critical in the design of deep radioactive waste repositories. Water is expected to reach the interface zone after the re-saturation of the geological massive and its presence may lead to concrete leaching. Such a phenomenon could increase the interface transmissivity and compromise the confinement of radioactive waste. Recent experimental results from Buzzi et al. (2008) have enhanced how concrete leaching can drastically change the mechanical behaviour of such interfaces. Because of the local loss of strength resulting from leaching, shearing resulted in a degradation of the interface asperities. Similarly to rock joints, intact interfaces exhibit a usual contracting-dilating behaviour. On the contrary, depending on the extent of leaching, the degraded interface can display a fully contracting. This paper intends to investigate the influence of concrete leaching on the mechanical behaviour of host rock-concrete interfaces. The leaching process consists in the dissolution of some of the hydrates of the cement paste, leading to a reduction of the strength and Young&apos;s modulus. A discrete model has been developed with PFC3D where a simplified interface morphology has been introduced using a saw-tooth description of the asperities.

May 1, 2009

En quoi consistent les études de suivi des effets sur l?environnement (ESEE)? Les ESEE constituent une méthode de suivi scientifique que l?on peut employer pour déterminer la santé des écosystèmes aquatiques (qui peuvent être touchés par l?activité humaine) et l?efficacité des mesures de protection de l?environnement. Les ESEE sont des évaluations scientifiques itératives du poisson, de l?habitat du poisson et des ressources halieutiques. Le programme comporte des phases séquentielles de deux à six ans de suivi, d?interprétation et de compte rendu au cours desquelles la fréquence et le type de suivi dépendent des résultats des études précédentes. Le programme des ESEE pour les mines de métaux est fondé sur un accord conclu à l?unanimité entre les intervenants. Les exigences du programme et les guides techniques connexes ont été élaborés à la suite d?une consultation multilatérale à laquelle ont participé les représentants du secteur privé, du gouvernement et des collectivités. Toutes les mines assujetties au Règlement sur les effluents des mines de métaux (REMM), aux termes de la Loi sur les pê ches, doivent procéder à une ESEE dans le cadre de l?autorisation qu?ils ont reç ue de rejeter des effluents. Le REMM a été enregistré le 6 juin 2002 et publié dans la Partie II de la Gazette du Canada le 19 juin 2002 (SOR/DORS/2002-222).

Nov 1, 2002

By M. Hitch, M. B. Lytle

Resource development conflicts arise largely due to differences in worldview between those who support and those who oppose development. This paper illustrates how societies and civilizations with different worldviews produce different levels of creative and economic energy. A questionnaire was created to build a database of responses to test whether worldview and resource development are correlated. Factor and multivariate regression analysis determined correlations for respondent groupings. Results showed a positive correlation between the respondents\u2019 worldviews and their attitudes toward resource development. Correlations became stronger as the homogeneity of the sample subgroups increased.

Jan 1, 2017

By Leroy C. Stewart

Owing mainly to the use of ethylene dibromide in the production of tetraethyl lead for gasoline treatment, there has been a tremendous increase during the past decade in the demand for bromine. In the United States, production, derived mainly as a by-product from the treatment of brines from salt wells, rose steadily from about two million pounds in 1924 to nine million pounds in 1931. In 1936, production amounted to between 20 and 21 million pounds. Much of the increase during the past four or five years has been due to the operation of the Ethyl-Dow Chemical Company&apos;s plant, which extracts bromine directly from sea water. The process employed by the Ethyl-Dow Company is somewhat similar to that in use on salt-well brines at their plant at Midland, Michigan, but whereas these brines contain around 1,300 parts per million bromine, sea water contains only 65 to 70 p.p.m.-about as much as the waste effluent in the brine process. By intensive research, however, a process was developed whereby a very considerable percentage of the bromine content of sea water could be recovered, and at a satisfactory operating cost. In its essentials, the process consists in liberating the bromine from the sea water by treat-ment with chlorine, blowing the bromine out of the water by a current of air, and finally absorbing it in a solution of soda-ash.

Jan 1, 1938

By J. L. Jambor, R. W. Boyle

"The Magnet Cove barite-sulphide deposit is a raking pipe-like body that replaced and partly filled a large brecciated zone at the junction of two faults at the contact between sedimentary rocks of the Horton and Windsor Groups of Mississippian age. The principal minerals in the deposit are siderite, barite, hematite, pyrite, marcasite, galena, sphalerite, chalcopyrite, tennantite, proustite, pearceite, acanthite and stromeyerite. The mineral assemblage and textural relationships indicate that the minerals were deposited from low-temperature solutions. The source of the elements in the deposit is believed to be the enclosing sedimentary rocks, with connate or ground waters as the transporting medium, and solubility products as the governing factor controlling the abundance and order of deposition of the minerals."

Jan 1, 1966

By F. Hassani, D. O’Donnell, M. Momayez, P. Guevremont

Shotcrete is a practical and economical support system in many Canadian underground mines. Although shotcrete technology has gained acceptance in the mining industry, there are some problems that have emerged with respect to quality assessment and thickness measurement of the liner. This paper presents recent tests performed with miniature seismic reflection technology (MSR) developed and patented at McGill University primarily for thickness measurement of this heterogeneous liner. MSR is also capable of providing information regarding the quality of shotcrete in terms of its mechanical properties such as modulus of elasticity and Poisson’s ratio. Work was performed on site in an underground mine in Ontario, Canada. This paper also presents the results from laboratory tests performed on fiber-reinforced and non-reinforced shotcrete panels that were used to assess the P-wave velocity in both materials. The results of these tests were used in a second site investigation. The NDT thickness measurements showed good agreement with direct thickness measurement such as coring. In addition, the MSR technology has the advantage of being more accurate and more affordable compared to other non-destructive testing (NDT) systems in the market.

Jan 1, 2002