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By Liu Liu

In the recent 10 years the rapid development of Chinese steel industry has attracted the attention of the world. The technological progress of converter steelmaking has played an important role in this process. First of all, slag splashing has been extensively adopted by Chinese steel companies in various sizes of converters from largest to smallest ones, and even including those using special hot metal containing V and Ti. Remarkable metallurgical results have been achieved. Up to now the average converter campaign life has reached nearly 10,000 heats, and the longest exceeds 30,000 heats in three melt shops. Based on this process, the long-life combined-blowing converter steelmaking technology has been developed. Slag splashing has been used to form a gas permeable "slag mushroom" on the top of bottom nozzles to protect the nozzles. In order to keep the effective bottom blowing, furnace bottom thickness control technique has been developed to prevent the furnace bottom growth. It makes the service life of bottom nozzle the same as the converter campaign life (average 10,000 heats and longest > 30,000 heats). The complete combined blowing was ensured through out the furnace campaign. Concentration product [C][0] is in the range of 0.0023 ~ 0.0030%, the T.Fe in the slag is lowered by 4 ~ 6%, and the [0] in steel is decreased by 100 ~ 250 ppm.

Jan 1, 2004

By Karl J. C. Harries

"11.1. INTRODUCTIONA royalty is the most common form of interest retained by an owner who is disposing of his property or by a joint venturer who ceases, voluntarily or otherwise, to participate in the joint venture.1 Rarely does a non-participating party have a direct interest in the property and/or assets of a project, except during the period when a non-participating joint venturer may be having his interest diluted.2 In fact, it is most unwise to permit a non-participating party to have such an interest. It may give rise to significant problems that could prevent or substantially delay the development of an orebody and require a considerable amount of time, effort, and money to correct.3In negotiating a royalty, it is important to be aware that there is no law or convention that says, “You just don’t do that in a royalty agreement.” As with any agreement, inventiveness and flexibility on the part of the negotiator are not just assets, but virtual necessities. It is also for this reason that it is essential to read the royalty provisions, particularly the definitions, fully and carefully, especially if you are the recipient. On the other hand, if your inventiveness and flexibility cause your accountant to question the advisability of one of your ideas, pay close attention to him.4 He will, no doubt, have had experience with many royalties, and no competent professional adviser disparages a client’s ideas without good reason. Besides, he will probably be the person who will be determining the royalty or certifying the determination of it. At the very least, he will be auditing your general financial statements, which must, of course, reflect the royalty determination. Heeding his advice not only may make the determination easier but also will probably save you money in professional fees later on. Nevertheless, do not simply accept his comments or recommendations without understanding what they mean, why they have been made with respect to your royalty agreement (sometimes professionals have comments that they make as a matter of course and, even though they may be valid, you should require them to be justified to you), and how they will affect your royalty determination.It is surprising how many corporate payors insist that their standard royalty provisions5 be used as a matter of policy, thereby effectively tying the negotiator’s hands. It is even more surprising, and to professional advisers frightening, how many of the senior employees who insist that such a policy be adhered to, virtually without variation, do not know what is in the standard provisions and would be hard-pressed to explain them to a property owner. If standard provisions are appropriate, by all means use them, but do allow experienced and sensible negotiators some flexibility and make sure that everyone within the corporation who may have to use such provisions – negotiator and supervisor alike – knows what they contain and why they are as they are. For example, there are often good and convincing reasons to describe a deduction in a certain way or to include a certain specific type of deduction. On the other hand, quite often the answer to the question “why?” is that “it has always been there”; this is, or should be, an unacceptable answer. In any event, if you, as the negotiator, appear to know what you are talking about, are familiar and comfortable with your royalty provisions, and are backed up by your boss with the same words or reasoning, a property owner cannot help but be satisfied that you are knowledgeable, even if he still does not agree with your provisions. Finally, if you do use standard provisions, make sure that they are reviewed and updated regularly."

Jan 1, 2003

By A. Warczok

Metal losses in discard slag are the main factor determining overall recovery. The metals are present both in dissolved form and as matte or metallic inclusions, varying in size from 2 to 1000 µm. Pyrometallurgical slag cleaning usually consists of heating the slag, reduction of oxides and settling of matte/metal droplets. Heating the slag decreases viscosity and accelerates reactions. Reduction of magnetite liberates inclusions and facilitates co-reduction of dissolved metal oxides. A significant amount of the matte and metal is present as very fine metallic inclusions, too small for settling. The coalescence of these matte or metal inclusions is required to remove them from the slag. The developed new concept of slag cleaning combines DC furnace technology with an extra magnetic field for vigorous slag stirring, enhancing mass transfer to the reductant surface, accelerating the rate of reduction, and destabilizing the emulsion of matte or metal inclusions. Intensive slag stirring increases the probability of collision of inclusions, will accelerate their growth and will therefore improve settling. The process is carried out in a patented DC channel furnace, where the liquid metal or matte layer acts as a cathode and the floating coke bed on the slag surface is the anode. In the first part of the furnace, a superimposed magnetic field induces a Lorentz's force causing the slag to start an intensive circular motion. The next furnace zone does not experience any stirring and is dedicated for quiet sedimentation of the inclusions. A mathematical model of gravitational coalescence combined with forced slag motion showed the possibilities of effective removal of copper matte inclusions. The results of laboratory pilot scale tests of continuous slag cleaning showed fast slag reduction and confirmed the improved matte removal from the slag. Conceptual analysis shows the potential use of the technology in various other non-ferrous industries, like for example nickel plants. It is also possible to use this technique batch wise.

Jan 1, 2007

By M. R. Hudec, M. A. Nikolinakou, P. B. Flemings

"We model the shale response to the large deformations associated with salt bodies, and we identify the implications of the stress changes for hydrocarbon exploration. We employ both the static and evolutionary approach, and show that while the static one can model actual geologic geometries, only the evolutionary approach can provide a detailed description of the stress history of shales, which is essential for predicting stress, porosity, and pore pressure and, more generally, for understanding Earth processes related to salt-hydrocarbon systems.INTRODUCTIONDuring the last two decades, understanding the stress, material behavior, and pore pressure in shales around salt bodies has become increasingly important. The energy industry routinely drills near salt (Beltrão, Sombra, Lage, Fagundes Netto, & Henriques, 2009; Meyer, Zarra, Rains, Meltz, & Hall, 2005; Seymour, Rae, Peden, & Ormston, 1993), because a significant number of hydrocarbon reservoirs around the world are found in layers dipping away from salt diapirs.Salt is a viscous material that cannot sustain deviatoric stresses. Under differential loading it flows, changes shape, and eventually relaxes to an isostatic stress state (Urai & Spiers, 2007). Therefore, emplacement of a salt body and its viscous relaxation process may cause significant deformation of the surrounding sediments, perturb their state of stress and create local overpressures (Dusseault, Maury, Sanfilippo, & Santarelli, 2004; Seymour et al., 1993). As a result, drilling near salt is particularly challenging, and problems leading to additional expense or even abandonment are common (Bradley, 1978; Dusseault et al., 2004; Meyer et al., 2005; Seymour et al., 1993; Willson et al., 2003).Historically, salt and the evolution of its cross section to the present day geometry have been studied using kinematic restorations (Rowan & Ratliff, 2012). This approach aims to explain the present geologic section through a sequence of plausible past sections; however, it does not model the constitutive response of the wall rocks, hence it cannot provide any prediction on their state of stress. Similarly, largestrain numerical studies (Albertz & Beaumont, 2010; Chemia, Schmeling, & Koyi, 2009; Goteti, Ings, & Beaumont, 2012; Gradmann, Beaumont, & Albertz, 2009) have focused on the rheological evolution of salt systems without modeling the geomechanical response of the sediments."

Jan 1, 2015

By J. D. Wright

This paper describes current milling practice at Endako Mines Ltd., a molybdenum producer in central British Columbia. The various steps in the crushing, grinding and flotation of the ore are outlined, with emphasis on the metallurgy of the latter operation. Tailings disposal and concentrate assaying methods are also described.

Jan 1, 1969

By Jerry Ran

Many large underground mines using the open stoping method have changed their primary applications of consolidated rock fill (CRF) to paste or consolidated hydraulic fill due to considerations of demand in infrastructure and equipment, system reliability, backfill capacity and material sources. However, some smaller or even large mines still use or consider using CRF for backfill purpose due to factors such as capital expenditure, availability or suitability of other fill types or in some cases local regulatory requirements. As demands on CRF applications diminish among major mining companies, there is a lack of recent literature on application of CRF to open stoping in design and operation. There are several methods being used for fill strength design. Results from these methods have been successfully applied to paste or hydraulic fill. However, the design strength for CRF is much higher than that determined by use of these widely accepted methods. In operation, CRF preparation and placement have significant impacts on the quality of placed CRF and therefore the mining performance. This paper reviews the current fill design methods and their applications to open stoping with presentation of the bench marking data, presents fill failure cases and various CRF preparation and placement arrangements and discusses quality assurance and control programs.

Jun 1, 2012

By Karl J. C. Harries

"4.1. INTRODUCTIONThis chapter, although divided into four parts, deals with only two principal topics. The first briefly describes and discusses some common types of property interests and considerations relating to them and the second deals with entering upon privately owned lands and obtaining the consent to do so.It should be noted that the terms “mining rights” and “mineral rights” are used interchangeably. As so used, they include the right to exploit the minerals and dispose of them for the benefit of the owner/lessee. This is relatively common in common law jurisdictions. In some jurisdictions, the two terms have distinct meanings, with “mining rights” referring to the right to work or exploit the minerals and “mineral rights” referring to the minerals themselves.Finally, it must be mentioned that the comments in the Introduction and §§ 4.2., 4.3. and 4.4. are based primarily upon Ontario law and Ontario’s mining and real property systems of registration. They have been included for illustrative purposes.4.2. LICENCES, CLAIMS, AND LEASESIn most jurisdictions, there are several basic types of interests that can be obtained from the state for mining purposes and that are of interest to the explorationist, as opposed to the operator. Different jurisdictions will have variations of these and possibly some extra ones that will address special purposes or local concerns. In virtually every jurisdiction, privately owned property rights are obtained through negotiation between owner and acquiror.Exploration or prospecting licence. This licence grants to the holder the right to prospect over a large tract of land and the exclusive right to acquire mining claims within that tract for the term of the licence. Such licences are usually negotiated documents requiring a minimum expenditure during the first year (often secured by a deposit or surety bond) and minimum annual expenditures thereafter to continue the licence in force up to its full term. The term will rarely exceed four years. The number of claims permitted to be staked will be limited in some way, possibly as to a maximum aggregate area or a maximum number of claims per annum. It is normal for the holder to have to drop part of the licensed area each year, so that the area shrinks annually, although exploration expenditure requirements will usually increase.These types of licences are usually used by governments to encourage exploration of otherwise unattractive or remote areas, such as the far northern parts of some of Canada’s provinces. They do not grant any real property interest in the area for which they are issued, and they will be subject to any claims or property rights that exist in the area. They are contracts with the state that grant certain exclusive rights in return for commitments to carry out work. They may or may not be specifically authorized by statute."

Jan 1, 2003

By Hans Lundberg

An electric survey from a 'plane flown over the ground is much faster and cheaper than an electric survey carried out on the ground. The results are obtained as continuous recordings that are resolvable into both a depth expression and a conductivity effect, so that the indications are easier to evaluate, as well as to correlate from one flown line to the other. The prospecting technique adopted in our electric airborne surveys may be brie fly described as follows: A loop of many turns of insulated copper cable is fastened around the fuselage of the 'plane and connected to a generator supplying a few ampere alternating current, usually of a frequency less than 1,000 cycles per second. Just as the current in the primary coil of a common transformer will induce current in the secondary coil when shorted, the alternating magnetic field from this primary current now induces alternating current in electric conductors that happen to be located in the vicinity of the path over which the 'plane is flown. This induced secondary current in each conductive section of the ground causes, in turn, an alternating magnetic field, secondary field, which disturbs or dampens the normal alternating magnetic field from the primary loop flown by the 'plane. These secondary fields are then picked up and recorded by the help of detecting solenoids, amplifiers, and recorders carried in the 'plane. By closer study of such a secondary field it is possible to localize the secondary current causing it and, thereby, the conducting body that contains the secondary current. In the 'plane are continuously recorded, besides the amplitude or intensity of the field, also the phase, which is a measure of how much the recorded secondary field is out of step with the primary field.

Jan 1, 1950

By A. S. Eve

The detection of magnetic dykes by using magnetic variometers is the oldest application of. geophysics to mining, and is also one of the more simple and certain methods 0f locating such deposits. As a result of recent improvements in the instruments, it is now possible to find the dyke, deter-mine with magnetic variometers its strike and dip', with fair accuracy, and to estimate the approximate depth of overburden when there is no outcrop. The application of electrical methods may be used to distinguish mineral from diabase dykes. The authors have had an opportunity of making surveys with the modern Askania types of vertical and horizontal variometers over magnetic dykes in the Sudbury region. The interpretation of the results has been confirmed by diamond drilling in some cases, and by experiments over models. The variometers used were the standard form of Askania instruments (1). The sensitivity of the horizontal type was 17.2 gammas per division, and that of the vertical variometer double this quantity. To make a preliminary survey of the district, parallel lines were laid off two hundred feet apart running north and south, and readings were taken with the vertical variometer every 100 feet along these lines. This can be done very rapidly, and when an indication of a magnetic deposit is found, the readings may be taken every hundred feet, or less if the size of the deposit warrants smaller intervals. If the deposit is a vein or dyke, the readings along the adjacent lines immediately indicate the strike of the body. Thus the presence and strike of a magnetic dyke, whether of mineral value like the pyrrhotite and nickel deposits of the Sudbury district, or simply a worth-less diabase dyke, is simply and rapidly found.

Jan 1, 1932

By Chunfeng Zhao, Chong Bao, Cheng Zhao, Jiashen Tian, Matsuda Hiroshi

"Based on digital image correlation (DIC) method and self-developed code, the global strain field changing and failure properties of rock-like materials with pre-existing double flaws are experimentally studied under uniaxial compression. By theoretical analysis with linear elastic fracture mechanics (LEFM), the strain approach proves to be practicable to investigate cracking process. Thus, two types of process zone are defined to discuss the specimen’s coalescence evolution at different loading stages. Crack initiation, propagation, and coalescence is a process of zone development and nucleation. DIC strain field results are studied on a meso-level using a strain approach. In the shear coalescence mode, the SPZ (shear process zone) in a bridge area coalesces with each other, while the TPZ (tensile process zone) grows independently. In general, the paper tries to establish the link between microscopic mechanical mechanisms and macroscopic mechanical responses in flawed rock. Further research should be done to study the cracking process and its effect on rock strength in detail by the DIC method.INTRODUCTIONNatural rock contains discontinuities including pores, fractures, inclusions or other defects. The existence of these discontinuities in the rock can decrease the strength and stiffness of the rock and they are a source of initiation of new discontinuities which may in turn propagate and link with other cracks and further decrease the strength and the stiffness of the rock (Sagong & Bobet, 2002). Lots of theoretical, experimental and numerical researches have been done in studying crack initiation, propagation and coalescence in rocks (Hoek & Bieniawski, 1965; Kranz, 1983; Reyes & Einstein, 1991; Park & Bobet, 2009; Gonçalves & Einstein, 2013). But when it comes to multiple pre-flaws, the issue that how the preexisting flaws affect each other becomes complicated and uncertain. The stress field around the tips of flaw can either enhance the impact of single flaw or weaken it. According to the observations have been done before, it is found that the way and function in which these cracks propagate and coalescence depends on the geometric arrangements (Bobet, 1997; Bobet & Einstein, 1998; Wong & Chau, 2001)."

Jan 1, 2015

By Andrukaitis. E.

The increasing use of electronic equipment by the Canadian Forces has increased the importance of electric power. A power source that is packed with energy and yet light, small and durable is the common request of military users. However, this needs to be achieved while also addressing the requirements of safety, reliability and low temperature performance. The potential use of fuel cells in a military environment has become a possibility in several areas in the 21st century. Some examples of power source requirements and the materials related R&D required to give better, higher energy power systems in the future will be discussed.

Jan 1, 2005

By J. C. Keenan

Company-community agreements are widely considered to be a practical mechanism for recognising the rights, needs and priorities of peoples impacted by mining, for managing impacts and ensuring that miningderived benefits are shared. The use and application of company?community agreements is increasing globally. Notwithstanding the utility of agreements, the gender dimensions of agreement processes in mining have rarely been studied. Prior research on women and mining, however, does show that women are often more adversely impacted by mining than men, and face greater challenges in accessing development opportunities that mining can bring, however there is currently little to no guidance for companies, government or communities in terms of bringing a gender perspective to the fore in mining and agreement processes. While it is undisputed in human development literature that investment in women and sensitivity to gender delivers long-term health, education and local development outcomes, a number of key factors remain unexplored in debates about mining and development. These include: women?s participation in agreement processes, the gendered distribution of agreement benefits, and the extent to which impacts and benefits influence (either positively or negatively) women?s development and economic inclusion. This paper presents the results of an applied research project undertaken by the Centre for Social Responsibility in Mining (CSRM) at The University of Queensland and funded by a partnership between the Minerals Council of Australia (MCA) and the Australian Agency for International Development (AusAID). The project sought to connect with practitioners who had been directly involved in agreement processes to hear grounded perspectives on the interaction of gender dynamics and agreements, and connect those experiences with the broader literature. Findings from this study have implications for the role of companies and governments in promoting gender equality and empowerment as part of their commitments to sustainable development. A key challenge for companies will be navigating the territory of cultural norms and gender equality. The authors argue that without consideration of the gender perspective, and appropriate responses, mining agreements may not be inclusive or representative and may exacerbate gender inequalities and fail to contribute to long-term sustainable development.

Aug 1, 2013

By McGill Metals Processing Centre, S. Chang, L. Calzado, X. K. Cao, C. H. Hsin, M. Isac

"Due to the increasingly stringent cleanliness requirements for final steel products, there has been a growing interest in the possible use of micro-bubbles for the removal of inclusions with diameters smaller than ~50µm, present within the steel passing through a steelmaking tundish. However, several technological barriers have prevented the adoption of this technique in industry. These are related to a) the generation of micro-bubbles in liquid steel, b) the measurement of bubble size distributions, and c) the optimization of bubble injection conditions to create micro-bubbles. In the present study, a novel Aqueous Particle Sensor (APS) system was developed for the in-situ, on-line, detection of micro-bubbles in water, generated by a newly designed full-scale ladle shroud, located at McGill Metal Processing Centre (MMPC). Measurement results from the sensor were validated against bubble size data collected through a high speed camera and post-processed through the commercial software, Image J.Control variables and orthogonal experiments were designed to assess the dependence of average micro-bubble sizes and bubble size distributions on key experimental parameters. Those chosen were the air inlet flowrate, the distance of the gas injection port from the slide gate, and the number of injection ports used. The investigation demonstrated that the APS system can be successfully adapted to detect micro-bubbles up to ~800 micron diameters. Using this novel sensor, it was shown that multi-port injection using low air inlet flowrates, closer to the slide gate, were useful in forming small micro-bubbles within the flow through the ladle shroud. The results from the APS system were compared and validated against data resulting from an optical technique. INTRODUCTIONModern industry expects increasingly stringent cleanliness requirements for final cast products. Therefore, the numbers and sizes of inclusions need to be strictly controlled in steelmaking operations. Thus, the cleanliness of steel products depends on the amount, morphology and size distributions of nonmetallic inclusions in steel (Zhang L. & Thomas B., 2003). Since large, deep, tundishes provide longer nominal residence times for liquid steel passing through it to the exit SEN’s, this can provide the ideal place to separate inclusions, and bubbles can assist by removing help attach inclusions and float them to the top surface."

Jan 1, 2016

By C. O. Swanson

THE purpose of this paper is to discuss the use of the dip needle in the field of mining geology. The subject matter is new only to the extent that it reflects the writer' s added experience in recent years. The treatment is brief, and those interested in a more extended analysis are referred to the articles listed at the end of the paper. In the discovery and tracing of mineral deposits, the clip needle, like most other geophysical instruments, can be used in two ways. One method may be termed direct; the other, indirect. The direct method is that of finding or following certain ore-bodies by virtue of their magnetic properties. Explicitly, or by inference, it is the method which many mining men and practising geophysicists have in mind when they consider whether or not a certain property should be studied by geophysical means. In the ideal case, this method demands little or no knowledge of geological conditions. The indirect method uses the clip needle as an aid to purely geological studies in working out the structure of a mineralized area. Although not as simple as the direct method, it enjoys a much wider field of usefulness. The writer's experience in the past fifteen years, which is believed to be typical, is that the indirect method finds application four or five times as often as the direct method. The indirect method is of particular value because it furnishes information concerning the relationship between geological structure and ore occurrence. Most mining engineers will agree that structural control is an important factor in the localization of ore deposits, and therefore that the subject under consideration is of some interest in mining geology. Specifically, then, the present purpose is to outline the principles and practice of using the clip needle in working? out geological structure.

Jan 1, 1941

By N. Erarslan, M. Serati

"This paper attempts to provide a simple analytical solution for the calculation of the stress tensor induced in a two-dimensional elastic ring of a brittle material subjected to general loading on either its internal or external curved surfaces. Airy stress functions and Michell’s expression in polar coordinates are used, and parametric studies are performed to investigate the influence of loading angle and the geometrical aspect ratio of the ring on the maximum induced tensile stress. INTRODUCTIONA proper and accurate estimation of the tensile strength of a given material is a crucial step in many engineering projects; in particular in rock cutting, since rocks are much weaker in tension than in compression or shear. Both direct and indirect laboratory techniques such as the direct uniaxial pulling test, the Brazilian indirect tensile test (also known as the split cylinder test), and the ring test have been proposed and developed to estimate rock tensile strength. Among these, the ring test, initially suggested by Ripperger and Davids (1946), has become particularly appealing for its ease of sample preparation and its unique breakage mechanism in almost a pure tensile mode. Unlike the Brazilian test in which high shear stresses developed in the vicinity of the contact could interfere with the tensile breakage of the disc specimen, a tensile failure starts away from the loading platens in a ring test (Hobbs, 1964)."

Jan 1, 2015

By Zhiqiang Wang

This paper mainly focuses on the method of ?three-zone? definition (a caving zone, a fissure zone and a curve subsidence zone) for full height cutting in a thick seam. Based on criteria of a caving zone and a water conducting zone, as well as existing research achievements, it is believed that there exists great error for calculation of height of the ?three-zone? area using cutting height and the coefficient of bulk increase. Dynamic factors should be considered, so, based on the theory of key rock strata and combining this with several other factors, such as mining area, this paper presents a new method to determine the overburden ?three-zone? definition. The results are as follows: (1) geometric models of a working face and key stratum are established through the rock displacement angle, with consideration of the influence of mining on the key stratum (the range of key stratum influenced by mining is enlarged as the mining area increases); (2) because there is always a cavity below the key stratum of the thick coal seam with full seam cutting, and the key stratum gradually fracture with face advancing, based on the geometric dimension of strata, the maximum fracturing interval expression has been presented, including the working face advancing range. This can theoretically lead to the location of the key stratum influenced by mining, and its stability before mining, helps to confirm which zone the key stratum and following-up strata belong to, using the criteria of sliding instability or deformation instability; (3) the new method of ?three-zone? definition which is based on the theory of key rock strata is first proposed for full height cutting in thick seam. Finally, combined with practical engineering, and comparing with field data, it is believed that the proposed method is more objective than existing methods.

Aug 1, 2013

By C. W. Van Law

WE have just heard a very able presentation, by Mr. J. C. Cameron, on the subject of Recent Trends in Labour Relations, as they exist today in Canada (l). With minor changes, what he said applies equally to the situation in the United States. Direct negotiation between employer and employee on a man-to-man basis, wherein good faith and mutual esteem was at least sometimes a factor, has almost entirely given way to a mass struggle in which each side is represented by highly trained specialists in a new jurisprudence, built up on vote-getting labour laws, decisions in analogous cases by Boards whose members may have had very little personal acquaintance with the specific case, etc., etc. Membership in a labour union has become almost an essential requisite to a job; once in, the individual workman loses his identity and dares not act on his own initiative or even express any idea not handed him by his Union head. An honest workman cannot turn in an honest day's work, because his Union will not allow him. Leadership in the Unions has become so powerful an instrument, both politically and monetarily, that Union policies are drafted primarily to build up that power, and may have little relation to the equities of the individual case. ?While both sides still render lip-service to the doctrine that Capital and Labour can advance best by co-operation to mutual benefit, that doctrine has in effect given way to as bitter and as legalistic a struggle as any in our civil courts. There are many reasons to believe that we are, industrially, in a situation much like the European situation from 1935 to 1939; an impending war to the death with 'appeasement' as the only, unavailing, policy

Jan 1, 1945

By Angus D. Campbell

Introduction Gowganda forms part of the general Cobalt area. Its rocks and ores are very similar to those of the other parts of the area. While its total production of silver is only 4 per cent of that of the famous Cobalt silver camp, its 1928 shipments contained 42 1/2 per cent as much silver as those of Cobalt for that year. During twenty years of production, 15,000,000 ounces of silver have been shipped from Gowganda. Of this, over 8,000,000 ounces have been shipped in the past five years. The area has thus made for several years a substantial contribution to the wealth of Ontario. Its future depends to a great extent on the priee of silver, which is now, unfortunately, at a record low price. This paper is a discussion of how the Gowganda ore-shoots occur, together with some notes on the milling of the ores at the Castle-Trethewey Mines. The first part is written in the hope of stimulating further study of the silver occurrences, which may lead to further discoveries. The second part, besides being a matter of record, may be of some use to operators of small mills. The drawings in the several Figures illustrating the text are by W. D. Stroud, mine superintendent of the Castle-Trethewey Mines, the benefit of whose opinions I have had in compiling these notes.

Jan 1, 1930

By J. S. Stewart

THIS paper was prompted by a persistent demand for what information we have that will throw light on the oil and gas possibilities of the Maritime Provinces. The problems involved were made familiar to the writer during three seasons of field work in New Brunswick and Nova Scotia. The reasons for renewed interest are: (1) In many parts of that region, the surface is underlain by a thick series of unaltered sedimentary rocks. (2) Oil seepages occur, and oil in commercial quantity has been exploited' near Moncton, New Brunswick, for many years. (3) In recent years, a new method of attack has been developed toward the finding of stratigraphic traps. This method is based on a detailed study of the geological history of the region, as revealed in surface outcrops and samples from deep wells. The well samples show the lateral variation of strata, far from any possible surface outcrop of the same beds. Sufficient work has now been done in the Maritime Provinces to reveal the broad features of the geological history and the character and distribution of the various rock formations. Comparatively little deep drilling has been done in this region, but the holes are widely scattered and the samples from them have added much to the information obtained from the numerous outcrops of bed-rock. The following discussion gives a summary of available information that has a bearing on the subject.

Jan 1, 1943

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