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By M. Arvola, A. Mäkinen, N. Isomäki

Arsenic is a compound that has no significant market value. However, it needs to be removed from ores, concentrates and other process streams because of environmental or technical processing concerns. A wide range of arsenic containing minerals exists in nature, and in many instances these minerals are also associated with the ones that have commercial value. For example, sulfide copper ores are normally closely associated with minerals like enargite, Cu3AsS4 and tennantite Cu12As4S13. After mineral processing these arsenic sources can report to the waste waters and these effluents need to be treated before discharge or recycling. Ferric arsenate precipitation is a well-established method for stabilizing arsenic in effluents. Electrochemical arsenic removal utilizes the same adsorption/precipitation ideology as ferric arsenate precipitation. Electrochemical arsenic removal, even though it is a simple process in terms of equipment, is a complex system involving chemical and physical mechanisms taking place simultaneously to remove dissolved and/or solid arsenic components from wastewaters. The whole process can be described by the following three steps: 1) electrolytic oxidation at a sacrificial anode (dissolving electrode metal, iron for example), 2) chemical reaction between dissolved iron and arsenic to form a solid precipitate and 3) aggregation of the particles to form flocs, which can be removed by known solid/liquid separation methods. Electrochemical arsenic removal is a very efficient way to remove arsenic from different waters to very low residual concentrations.

Jan 1, 2016

By Cardm Jeffrey W.

The decay of 222 Rn yields a series of short-lived decay products which become attached to the surface of a plate or wire exposed in a 222Rn-bearing atmosphere. The alpha-activity of two of the decay products, 218Po and 214Po, can be measured by simple counting techniques. This phenomenon may have direct application to uranium exploration. Laboratory studies have shown that: (a) radon decay products can be collected on a wide variety of materials (including various kinds of metals and plastics); (b) activity increases as a function of the surface area of the 'collector; and (c) the collection of the decay products is enhanced by applying a negative charge. The new technique was used in situ to delineate the anomaly above the South March uranium-copper occurrence. A related technique was developed to measure radium in soil samples. The results of both studies compared favourably with those obtained from conventional methods.

Jan 1, 1979

By J. Shang, P. Howarth, B. Morris

Tailings from the nickel refinery in Copper Cliff, Ontario, consist of fine silicates mixed with a variable amount of conductive and magnetic minerals mainly associated with sulphides and iron oxides. Subsequent oxidation of sulphide- rich phases within the tailings results in the formation of an acidic leachate that may contain significant concentrations of trace metals. Mapping the spatial distribution of regions of higher sulphide concentration therefore provides insight into the distribution of the acidgenerating potential within the tailings. Electrical conductivity is constrained by two parameters — the concentration of metallic sulphides and the ionic concentration of acid in groundwater. Magnetic susceptibility is directly related to the pyrrhotite and magnetite content. It is proposed that combining information derived from airborne electromagnetic and magnetic surveys can provide an indication of metallic sulphide distribution. Preliminary investigations of airborne electromagnetic and magnetic data acquired concurrently over the sulphide-rich Copper Cliff tailings site reveal that these parameters can provide information on mine tailing extent and permit separation of tailings with varying compositional and alteration levels. Airborne geophysical data provide information about the subsurface while a digital elevation model (DEM) and hyperspectral imagery record surface conditions. Integration of the two data sets can reduce ambiguity when interpreting mine tailing distributions and their subsequent alterations.

Jan 1, 2001

By Jonathan Allen, Peter Radziszewski

"Stirred mill technology dates back to 1928 where the idea to use “an agitator and spherical grinding media” was presented. The year 1948 saw the successful application of DuPont’s “sand mill” for pigment grinding. Subsequent years have led to the development of different types of stirred mills spanning a number of industries that require fine and ultrafine grinding. In the context of the mining industry, smaller grain size and other mineralogical characteristics have motivated the need to grind finer. In order to address this need, the interest in stirred milling technologies has grown over the last 20 years as can be illustrated by the large body of literature published over this same period of time. The typical observation reported in the literature is that in certain circumstances stirred milling is significantly more efficient than ball milling. Despite these developments, the tumbling mills are continuing to be used in fine and ultrafine grinding applications. The main reason for this, as communicated at the Canadian Mineral Processors roundtable discussion in 2013, is that the comfort level in understanding stirred milling technologies is not at the level of that of tumbling mills. The aim of this paper is to contribute to increasing the general comfort level with stirred milling technologies by developing a better understanding of how power and energy is affected by stirred mill impellor design and mill operation. This will be accomplished by first completing an overview of the power models found in the literature followed by a general description of DEM and CFD stirred mill models as well as the insights that can be drawn from them. Finally, a generic stirred mill power model will be presented and applied to different stirred mill types in order to develop some insights into the differences between different mill types. The paper will close with a discussion on some of the challenges that these models have and how future research might contribute to overcoming them."

Jan 1, 2014

By Trevor Yeomans

"NVI Mining’s Myra Falls Operation is a forty year old underground mining operation feeding a 4000 mtpd concentrator.The current Mill, built in 1985, was designed to process a large massive sulphide ore-body. This ore-body, known as the “HW”, contains about 50% pyrite. Value minerals are chalcopyrite, and sphalerite, with precious metals occurring in all mineral types.By 1997, mining of a new ore-body, known as “Battle-Gap” commenced. Mineralogically complex, the new orebody contains about 15% pyrite, copper minerals including primary chalcopyrite, secondary bornite, chalcocite and tennantite, combined with increased galena and sphalerite.Flotation performance generally decreased with increasing amounts of Battle-Gap ore types, with both copper concentrate quality (increased lead and zinc content) and copper recoveries being affected.Following significant metallurgical testwork, a new fully sequential copper-lead-zinc flotation flowsheet and reagent scheme was developed.This sequential flowsheet was progressively installed and commissioned during 2006.Copper concentrate lead and zinc smelter penalty contents have been reduced by some 40%, whilst increasing copper recovery by 10%.INTRODUCTIONNVI Mining operates the Myra Falls Operation near Campbell River on Vancouver Island, BC. The complex has been in operation since 1966 with mining being predominantly underground. One unique feature of Myra Falls is that the mine operates within a BC Provincial Park.In 1985, a new large massive sulphide ore-body (HW) had been defined, and metallurgically tested. A new concentrator was built based upon this massive pyrite, chalcopyrite, and sphalerite mineralization producing copper and zinc concentrates by conventional flotation methods."

Jan 1, 2008

By Stephen A. Gasiorowski, Frank J. Hrach, James D. Bittner

Separation Technologies, LLC (ST) has developed a processing system based on triboelectric charging and electrostatic separation that provides the mineral processing industry a means to beneficiate fine materials with an entirely dry technology. The environmentally friendly process can eliminate wet processing and required drying of the final material. The process requires little if any pre-treatment of the material other than grinding and operates at high capacity - up to 40 tonnes per hour by a compact machine. Energy consumption is low, approximately 1 kWh/tonne of material processed. Since the only potential emission of the process is dust, permitting is typically relatively easy. In contrast to the other available electrostatic separation processes that are typically limited to particles greater than 75 µm in size, the ST belt separator is ideally suited for separation of very fine (<1 µm) to moderately coarse (500 µm) materials with very high throughputs. The triboelectric particle charging is effective for a wide range of materials and only requires particle-particle contact. The small gap, high electric field, counter-current flow, vigorous particle-particle agitation and self-cleaning action of the belt on the electrodes are the critical features of the ST separator. The high efficiency multi-stage separation through charging / recharging and internal recycle results in far superior separations and is effective on fine materials that cannot be separated at all by the conventional electrostatic techniques. Since 1995, this triboelectric process has been extensively used for the beneficiation of coal fly ash with eighteen separators in place and over 100 machine-years of operation at locations in North America and Europe. The technology has been also successfully applied to the beneficiation of a variety of minerals including calcium carbonates, talc, and potash.

Jan 1, 2012

By R. Barbaroux, B. Dubreuil, D. Lemieux, K. Nasrallah, G. Garcia Curiel

"As conventional, base or precious metal ores are being depleted worldwide, the mining industry is being faced with an increasing exploitation of arsenical sulfidic ores. Enargite is a common example. The downstream processing of these ores poses several problems ranging from high smelter penalties to finding economical and environmentally acceptable means of disposing of the arsenic. Several hydrometallurgical processes have been proposed for extracting arsenic from enargite concentrates, notably using alkaline sulphide leaching (ASL). However, few alternatives exist for removing the arsenic from solution and stabilizing it in an approach that is both economical and environmentally acceptable.Dundee Sustainable Technologies (“DST”) has developed a technology for the sequestration of arsenic by vitrification. Originally optimized to cost-effectively stabilize arsenic trioxide (As2O3), DST has shown that vitrification could be successfully extended to the stabilization of other arsenical products, such as calcium arsenate (Ca3(AsO4)2) and sodium arsenate (Na3AsO4). In this paper, the vitrification of arsenic in the context of an enargite leaching was newly explored and demonstrated successfully.Two processing routes are being proposed by DST for the removal of arsenic from enargite concentrates and their stabilization by vitrification. In one route, arsenic is extracted by ASL and is then precipitated under atmospheric conditions and with minimal use of reagents and time. The resulting precipitate is an unstable hydrated ferric arsenate (FeAsO4•2H2O) that is then vitrified in a non-dilutive method, significantly increasing the stability of arsenic and meeting the TCLP guideline. Unlike is required for scorodite, stabilization was successfully achieved without concern for the crystallinity of the precipitate."

Jan 1, 2017

By Sanjeeva Latchireddi, Travis Orser

"Today’s high capacity semiautogenous grinding (SAG) mills expend vast amounts of energy and in doing so consume tons of shell liners and steel balls, while processing ore. The energy efficiency of these high throughput grinding mills can be attributed to the field of breakage and slurry discharge system. The charge motion and breakage of particles inside the mill depends on the shell lifters design, while the discharge of ground particles is controlled by the grate and pulp lifters. The limitations imposed by poor grate and pulp lifter design become increasingly apparent with increasing size of ag/sag mills and their operation in closed circuit. The design of these mill components has been largely based on trial and error and hence varies considerably between manufacturers. This paper discusses the use of two state of the art design tools - Millsoft™ and FlowMod™. Millsoft™ is an effective tool to design the shell lifters and optimize charge motion, whereas FlowMod™ simulates the slurry discharge system to design grate and pulp lifters. The application of these simulators will be discussed using case studies of full scale mills.INTRODUCTIONMany large mining operations around the world have one or more semi-autogenous (SAG) mills doing bulk of the work in their size reduction operation. The SAG mill is usually followed by a ball mill to finish the size reduction prior to the concentration step. In the past when primary, secondary and tertiary crushers fed material directly to large ball mills, the energy efficiency of the concentrator was determined for the most part by the ball mill operation, whereas now the energy efficiency of a plant often rests largely on the SAG mill operation. As a result mines have shifted their emphasis in optimization from ball mills to SAG mill"

Jan 1, 2005

By Neil McMillan

"By any measure of common practice, Claude Resources' Seabee Gold Mine in Northern Saskatchewan should not now be operating. Not because reserves dwindled, or grade dropped or prices weakened or technical problems arose, but because a host of unimaginable other problems beset the project, any one of which would normally have led to the mine's failure.The success of the Seabee Mine, and it is extremely successful, is a story of the vision and blunt determination of two men. Neither is remarkable in his own right but each possesses the characteristics which were necessary to forge a highly productive and profitable narrow-vein mine in the midst of the most bizarre and unpredictable events which likely have ever beset a mine start-up in Canadian history.Together, Bill MacNeill, a Saskatchewan born, former bush pilot and Ray Gagnon, a big hearted, hard-fisted, miner with 44 years of experience in Canada's underground, built the Seabee Mine.They didn't accomplish this with brilliant geology, outstanding engineering or nimble corporate manouvering but rather a stubbornness and raw common sense which likely are all too often, ingredients missing in failed projects.The Seabee Mine is 100% owned by Claude Resources, a Saskatoon based company taken over by Bill MacNeill, its current chairman, in 1982. The company is listed on the TSE and produces 1200 barrels of oil per day and about 60,000 oz of gold per year. The company has a strong balance sheet, is very profitable and has 18 million shares outstanding.The Seabee property in Northern Saskatchewan started out like many other gold exploration properties in Canada.It was discovered in the l 940's by what is now Cominco, and, while highly regarded by that company the property sat largely dormant until acquired by Claude Resources in 1985.Claude did what most junior exploration companies would do and went looking for a company with a depth of expertise to joint venture the property.That company was Placer Development who could earn a 55% interest in the Seabee by delivering a bankable feasibility study on the Project by July 1988 and providing financing to production.Placer Development was an excellent company and spent over $8 million dollars on the Seabee over a 3 year period. Unfortunately for Claude Resources, Placer Development merged with Dorne Mines in 1987 and the new merged company, Placer Dome, established a minimum production threshold greater than the 50,000 oz per year which the Seabee appeared capable of supporting at that time. Placer Dome's request for an indefinite extension of the joint venture agreement to allow it to drill off a larger ore body was rejected by Claude Resources and the Seabee Property was returned to Claude in 1988."

Jan 1, 1998

By G. Tairova, M. Murchie, B. Esford, E. Lam

"The objective of this project is to investigate methods to lower the sulphate concentrations in the mill effluent. Currently, the concentration of sulphate in mill effluent is approximately 2 g/L. The high concentration of sulphate ion in the effluent has the potential to become a regulatory issue. The target sulphate concentration in mill effluent for this work was less than 500 mg/L. The pilot studies, using sulphate precipitation, were carried out at the mill. The results of the sulphate precipitation pilot study, using calcium hydroxide and sodium aluminate, indicated that:• The sulphate concentrations in effluent could be reduced to less than 500 mg/L.• The concentrations of most other elements of concern, such as selenium, arsenic, cobalt, nickel and vanadium, were also reduced.INTRODUCTIONHistorically, the concentration of sulphate, SO4 2-, in water has not generally been subject to regulation. However, with the increasing global consumption of water, stricter regulations on sulphate quantity may be imposed. Sulphate is a concern in process waters as it forms scale on process equipment and leads to operational problems. High sulphate concentrations may result in adverse health effects. The taste theshhold for the most sulphate salts in drinking water ranges from 250 to 500 mg/L.A literature search and review to identify methods to reduce sulphate concentration in the mill effluent was carried out. A number of methods were selected and tested in the lab. The experimental results indicated that the precipitation methods, using calcium hydroxide and aluminum compounds, barium compounds, as well as the ion exchange and the membrane methods, were effective for the removal of sulphate to below the required limits. Some other elements, such as vanadium, nickel, cobalt, selenium and molybdenum, were also removed.The process, using calcium hydroxide and aluminum compound for sulphate precipitation, similar to the Cost Effective Sulphate Removal (CESR), also known as “Walhalla” process, described in the Montana Tech report (“Demonstration Of Sulfate Removal” 1999), was selected for further consideration [1]. In the CESR process, the water is treated with lime for precipitation of gypsum, followed by the reaction with a proprietary aluminum compound for removal of a residual sulphate. The final pH adjustment is carried out using carbon dioxide. Results of a preliminary cost estimate indicated that the removal of sulphate using calcium hydroxide and aluminum compound was the preferred method of treatment, considering its low cost, availability of chemicals and minimal changes to the existing plant circuit."

Jan 1, 2012

By L. D. Smith

"Those who submit competing proposals for projects seek to present senior management with complete and fully supported material that will not fail under questioning. Hopefully, misleading notions and omissions will have been minimized and there will have been testing of the assumptions regarding the economic, social and political environments. A capital project evaluation team can do management and itself a service by including a sound approach to the impact of inflation (and its twin problem, interest) on a project and a great disservice with an inappropriate approach to inflation.InflationHandled deftly, inflation can alter a project evaluation to show almost any result the handler desires. It must be a constant source of frustration for design people and cost estimators to spend weeks perfecting the technical aspects of a project in order to minimize costs, only to have all of their efforts set awash in a sea of financial and economic assumptions that submerge all of the detail. In all of this, inflation is perhaps the largest offender, with inflation criteria often being brought to bear at the last minute, almost as an afterthought. Perhaps this tardiness reflects the difficulty of the subject and the belief that senior management will take its own approach to the problems of inflation. Such a belief is unfair to senior management, for it is entitled to not being misled by omission. It is entitled to the full use of the skills of the evaluating team, including respectable assumptions of the impact of inflation.Working in a consulting context, one has the opportunity to participate in the evaluation of a large number of projects. Reflecting the observation of a wide range of views regarding the subject of inflation, this paper will-address the impact of five different approaches to inflation on the evaluation of a single Canadian mining project."

Jan 1, 1987

By Philippe Poirier

Les parcs à résidus miniers représentent un risque environnemental qui nécessite une gestion adéquate. Suite à la publication du « Guide sur la gestion des parcs à résidus miniers » en septembre 1998, les membres de l?industrie minière ont appliqué les éléments de gestion du Guide, permettant ainsi une amélioration continue des opérations. En février 2000, l?industrie minière a indiqué le besoin d?établir des lignes directives plus spécifiques pour l?opération sécuritaire des parcs à résidus. Dans cette optique, l?Association Minière Canadienne a publié, en septembre 2002, un Guide pour l?exploitation, l?entretien et la surveillance (EES) des parcs à résidus miniers. Suite au développement du Guide et à son application sur plusieurs sites miniers, il apparaît que la mise en oeuvre d?un Manuel ESS des parcs à résidus miniers permet : ? d?établir les responsabilités des intervenants; ? de s?assurer que les critères d?opération sont appliqués; ? de mettre en oeuvre le plan de déposition des résidus et de gestion de l?eau; ? de rencontrer les normes et exigences environnementales; ? de définir un programme d?entretien et de surveillance des ouvrages; ? d?identifier les risques et de mettre en oeuvre un plan d?intervention d?urgence; de démontrer une opération diligente.

Nov 1, 2002

By C. V. Umipig, G. G. Hutalle, E. E. Israel

TVI Resource Development (Phils) Inc. Canatuan mine is a polymetallic ore deposit located in the Province of Zamboanga del Norte on the island of Mindanao in the Philippines. The deposit consisted of an oxidized capping of gossan overlying a Besshi type volcanogenic massive sulphide lens which is near surface and flat lying. Construction and development of a sulphide processing plant began in early 2007 and commissioned in November 2008. During the initial stages of sulphide operation, high copper (Cu)-low zinc (Zn) ore was fed to the plant. Marketable copper concentrate at 91-95% recovery was produced utilizing a high-pH bulk sulphide rougher flotation and 2 cleaning stages. Because of increased levels of Zn of the ore body, a Cu/Zn separation circuit was initiated in early 2010 following an intensive laboratory test work program. This Cu/Zn separation circuit was necessitated because of the copper ion pre-activation of the sphalerite that lead to the zinc being readily recovered to the copper rougher concentrate. In-situ activation of zinc (in the pit and stockpiles) was caused by the leaching of secondary copper minerals in the ore (particularly from the dominant copper species, chalcocite and covellite). This problem required the development of metallurgically complex and intensive reagent regime to effectively depress the activated sphalerite. As well, the immediate reactivation of zinc after it has been depressed, at the onset of Cu/Zn separation flotation, added additional metallurgical complexity to the process. Subsequent to the Cu/Zn separation circuit, an unconventional, yet proven effective, simultaneous cyanide detoxification-zinc flotation circuit was set-up to recover the zinc. Laboratory test work results realized Cu-Zn recovery differential from a Cu/Zn separation circuit of over 40-45%. This performance has been achieved in the plant, at 72% Cu overall recovery. With the gradual improvements on-going with zinc circuit capacity and effective zinc separation being achieved, zinc recovery has currently reached 40%.

Jan 1, 2012

By J. Chlopas, D. J. Barratt, M. V. Sharp

"This paper describes the modifications made to the Fox Mine copper concentrate bin in order to obtain a continuous flow condition. The design of these modifications is based on test results obtained on Fox Mine concentrate using the flow factor testing machine in the research facilities of Cominco at Trail, B.C.The original design consisted of a cylindrical steel bin on a concrete slab with two slot-discharge openings. Based on predictions of the maximum mass flow hopper angle for conical and wedge shaped hoppers for the concentrate on various potential bin lining materials, Ultra-High Molecular Weight (UHMW) Polymer was selected as a liner.Using the recommended angles for conical and wedge shaped hoppers, the profile of the bin base was changed to suit the existing slot openings.The initial method of fastening the liner resulted in failure of the connections. Subsequent modification to the zinc concentrate bin fastener system proved satisfactory and it has now been in operation for over one year without any separation of the lining material.Utilization of flow testing procedures on concentrate samples has demonstrated that proper design of storage bins or hoppers to achieve continuous flow can be incorporated into the design of new plants."

Jan 1, 1978

By T. Hidayat, D. Shishin, V. Prostakova, M. Shevchenko

The chemical compositions of copper feed streams are becoming increasingly complex following the growing demand for metals and corresponding shortages of primary sources. The optimisation of process conditions requires an accurate description of phase equilibria and thermodynamics. Integrated experimental and thermodynamic modelling research program on the characterisation of the complex, multi-component, multi-phase gas-slag-matte-speiss-metal-solids Cu2O-PbO-ZnO-Al2O3- CaO-MgO-FeO-Fe2O3-SiO2-S-(As-Bi-Ni-Sb-Sn-Ag-Au) system is being carried out to support companies undertaking the pyrometallurgical primary production and recycling of copper. The experiments involve high temperature equilibration in controlled gas atmospheres, rapid quenching and direct measurement of equilibrium phase compositions with quantitative microanalytical techniques, including electron probe X- ray microanalysis and Laser Ablation ICP-MS. The thermodynamic modelling is undertaken using FactSage computer package with advanced thermodynamic solution models. The continuing development of research methodologies has resulted in significant advances in research outcomes. Implementation of the results of these fundamental studies involves an ongoing collaboration of researchers and industry technologists. An overview of recent progress in research, implementation and applications in industrial practice are given in the paper. INTRODUCTION Rapidly developing technologies increase the demand for various metals in number and volumes. Modern technological devices such as mobile phones, computers, other electronic devices, have dozens of metals—all those metals have to be a) produced and b) recycled. The fast transition in mobility from fossil energy delivered through combustion to renewable energy first stored in bakeries and delivered through electric engines introduce a significant change in the metal demand in terms of both type and volume of metals. Pyrometallurgy is playing a key role in supporting these changes in our industrialised society.

Jan 1, 2019

By Gregg Hodges, Fred Schoenbrunn, Steve Slottee, Chad McCleary

"In December, 1999 Stillwater Mining Company (SMC) commissioned a new paste /cement backfill plant to supplement the existing sand backfill system for the cut and fill mining operation at it’s Nye, Montana mine. The new plant uses the Baker Process Deep Cone TM Paste Thickener to thicken the total concentrator tailings from 30% solids slurry to a 71% solids paste. This paper describes both general paste formation concepts and the evolution of the SMC paste plant operation from original design criteria, through problem solving and plant modifications, to the operation of the existing plant.Although the original process design was not effective for consistently producing and delivering acceptable paste to the stopes for backfill, SMC was able to make the mechanical and process modifications which allow the plant to now produce and deliver an acceptable product to the stopes. Ongoing test work is targeted at increasing the pumping range of the system, increasing the paste solids concentration from the Deep Cone Paste Thickener and reducing the operating and maintenance costs of the system.INTRODUCTIONThe authors would like to thank both Stillwater Mining Company (SMC) and Baker Process for their assistance in the preparation of this paper. Stillwater Mining Company chose not to participate directly in this paper due to time constraints, but was very helpful in answering questions concerning their approach to problem solving and specific details with regard to engineering criteria.This paper will begin with a general review of the technical and mechanical concepts in paste formation and then focus on the overall design, start-up and problem solving process for the paste backfill operation at SMC’s mine and concentrator near Nye, Montana."

Jan 1, 2001

By R. J. McLeod

"CONTROL STRATEGYThe Lake Dufault Division of Falconbridge Copper Limited has been concentrating a complex copper zinc ore since late 1964. An ARL X-ray on stream analyzer was installed in 1966 for process control. A Digital Equip-ment Corporation PDP8 was added in 1968 for more complete control. To improve the system the computer was exchanged for a Moded PDP-81 in 1971.The new computer is time sharing with 8K core memory and 32K disc storage. A new interface was installed to accommodate 14 X-ray streams and additional analog signals for process control. The system gave us additional capacity and flexibility to make changes in operating programs and control strategy while on line. As the computer is used for process control a modified focal language was chosen as the operating language for ease of operation. This language is more suitable for process control than for statistical work.The main components of the control system are(a) Computer(b) Interface(c) Production Control X-ray Quantometer(d) Teletype terminals(e)Reagent feeders(f) Sample SystemThe operation of the system consists in the computer selecting the various streams to be analyzed by a PCXQ Quantometer. When the flowing sample is presented to the X-ray the intensities of the various elements are read by the computer from analog to digital converter, the assays are then computed. From the tonnage and assays the computer is programmed to determine the amount of reagent added to various parts of the circuit. The computer drives the feeders via the interface for the required amount of reagent. After following a certain sequence the computer prints out the performance and control data on an ASR35 Teletype. The data is printed out approximately every seven minutes. Any des¬ired changes in the program or strategy can be made during operation via an ASR33 Teletype connected to the computer."

Jan 1, 1973

By C. M. Anson

Introduction The prosperity of any country today is dependent upon the efficiency and growth of its primary steel industry. The ?march of the United States of America to its present commanding position in world affairs parallels the growth of its steel industry. The remarkable growth of that industry was possible only because bountiful providence endowed that country with adequate supplies of the raw materials necessary for steel making -coal and iron ore. If we accept this hypothesis, and surely we must, then to what extent can we envisage the future of our own country? This symposium deals with the most important of the raw materials required for steel making -iron ore. If we are blessed with a bountiful supply of iron ore, then surely a glorious future awaits only our taking advantage of that blessing. It is becoming increasingly evident that Canada has immense iron ore deposits. It is my privilege to make you acquainted with one of these, one that can only be classified as among the more important ore reserves in the world. I refer to the Wabana ore deposits in Newfoundland. Location These deposits lie under the floor? of Conception bay, off the east coast of Newfoundland. They consist of a series of beds which outcropped for a distance of about three miles on the northeastern shore of Bell Island, dipping at approximately 8° toward the northwest. This three-mile outcrop is the only key to the occurrence.

Jan 1, 1951

By Harry Siewert, Tom Milner, Jack Stickney

"LocationThe Gibraltar mine is located in central British Columbia (NTS 93B/9W), 362 km north of Vancouver. Access is provided by 20 km of paved road from McLeese Lake, which lies 45 km north of Williams Lake on Highway 97. Latitude and longitude of the mine are 52° 30' and 122° 16', respectively.The total area of the McLeese Lake site is approximately 1700 ha (4200 acres). This includes the orebodies, dumps, surface drainage collection system, plant site, roads and tailings ponds.Brief Description of OperationOre is mined by open pit methods and is concentrated using conventional crushing, grinding and flotation processes. Copper and molybdenum flotation occurs at an average rate of 40 000 tons per day. Tailing is discharged to an impoundment area and the water recycled as process water. Additional copper is extracted from the waste dumps using sulphuric acid as a leach solution followed by solvent extraction and electrowinning.HistoryExploration by Gibraltar began in 1964, continuing until late 1970, at which time it was announced that the property would go into production. Construction started in early 1971, with initial production in March 1972. Target capacity of 30 000 tons per day was achieved by the end of March and is currently at 40 000 tons per day.Ore reserves as of January 1, 1998 were 184 384 000 tons grading 0.31% Cu and 0.010% MoS2."

Jan 1, 2000

By Norman Orr, J. W. Gregg, Jack Wahl

The Pembina Cardium pool is a low permeability, stratified, solution-gas drive reservoir. Water-flooding has proven to be an effective means of pressure maintenance for all areas of the pool in which an economic rate of water injection can be maintained. The majority of water injection wells in the pool are converted oil well~ with capacities greater than 100 millidarcy-feet. If the average injection rate per unit of capacity can be in-creased the lower capacity areas of the pool can be economically flooded. Theory, laboratory work, and two . early miscible-flooding projects with-in the pool suggested that average water injection rates for converted wells could be increased two to three-fold by the initial injection of natural gas liquids and natural gas. How-ever, these two early projects received volumes of natural gas liquid!:' and high-pressure natural gas which would be economically prohibitive for routine stimulation. Area D, one of the Five-

Jan 1, 1962