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By W. E. Selnes

Introduction In 1938, a survey conducted by the Ontario Mining Association revealed a rather startling fact. Injuries incurred in chute pulling were more numerous than those from any other single cause. This report prompted Mr. W. B. Paton, then Inspector of Mines for Manitoba, to make a similar survey of the mines of his Province. It indicated that, in Manitoba mines, chute accidents ranked second only to those from falls off roofs and sides. Why has the mining industry been so slow to recognize the dangers of chute pulling? A partial answer may be the lack of any systematic classification of accidents according to their real cause. The result has been to attribute to other causes injuries which were a direct outcome of chute pulling, and, indeed, has made it difficult to analyze accidents in the industry as a whole. Perhaps, too, because chutes are generally located in the comparative safety? of the drifts, there has been a tendency to consider the occupation as not very hazardous. Not until enough statistics were obtained on this particular task could it be appraised correctly. The Mining Association's survey has been most helpful, and latterly the industry has done a great deal toward analyzing the causes of chute accidents and toward determining an effective means of overcoming them. Much, however, remains to be done. An effort will be made in this paper to outline methods which have been found successful in materially reducing the number of injuries. Qualifications of the Chute Puller First of all it must be realized that chute-pulling is a specialized occupation. The men require proper training for the job, just as in other mining operations. Care must, therefore, be taken to choose persons whose qualifications fit them for the job. Chute-pulling is an integral part of the general mining operation and cannot be considered as isolated from the tasks of other workers. One of the essential qualifications of a chute-puller is a sufficient knowledge of mining operations to appreciate the effect his work will have on the safety of others in the vicinity. He must take the necessary precautions, by verbal warnings, by placing barricades and signs, or by personally guarding the chutes, to prevent accidents to fellow workers.

Jan 1, 1947

By M. E. Stutt, R. H. Rehder

"The mining industry is taking advantage of the increased performance resulting from the use of variable speed A C drives for large motors. This technology provides increased efficiency under the variable speed and torque requirements of such drives as mine hoists, conveyors, and air moving equipment. The technology does introduce voltage spikes on the voltage wave form that stress the insulation system to a greater degree than would occur with a constant voltage source. These voltage spikes must be considered in the design of the insulation system used for these motors.BackgroundHistorically the insulation systems for large AC motors were designed to withstand with reasonable life the voltage stresses of a 60 Hz constant sinusoidal voltage. One of the design tests is a voltage endurance test that requires the application of a 60 Hz voltage from conductor to ground equal to four to five times normal and establishing a time to failure. These higher than normal voltages accelerate the normal aging process by causing extensive partial discharge activity (corona) within the insulation system and the time to failure is a relative indication of insulation life.In addition to the voltage endurance test at 60 Hz, the individual coils are subjected to a surge voltage test to establish the withstand capability of the turn to turn insulation under switching surge conditions. The surge voltage is a fast rise time, 0.2 microsecond to crest value, voltage spike that can be caused by a circuit breaker or contactor closing operation. These voltage spikes can have a crest value of greater than 3.5 times the normal line to ground crest voltage of the normal 60 Hz power supply. The standard withstand test value is thus 3.5 times normal line to ground voltage. Because the voltage surges or spikes occur mainly during start and stop switching conditions, voltage endurance under these conditions has not been a major factor in insulation system design."

Jan 1, 1995

By U. Dillon, G. Blackwell

"Geographic information systems (GIS) provide an efficient means for the recording, manipulation, revision, display and analysis of spatially referenced data. GIS are widely used at the exploration stage of mine development, and are increasingly used for reclamation planning. The ability of a GIS to perform spatial searches and query spatially referenced data make it a powerful tool for use at all stages of mine development. As the amount of data available for analysis increases, so does the power and flexibility of GIS as a planning tool.Starting from the exploration database, this paper describes how a GIS can be used for the development of mining plans based on topography, geology and mineralization information stored in a relational database. Planning decisions approaching the optimal can then be made for a wide range of parameters, including stockpile and waste dump locations, the location of potentially acid generating and neutralizing material for dump design, profitable and risk-controlled mine extraction sequencing, and haul road locations. This is made possible by the overlay and buffer analysis capabilities of a GIS which are explored and exploited to produce a continuous mine production planning program, as well as site remediation and reclamation using a successful case study. The Ore and ProductsThe mines in the Saskatoon area — Agrium, PCS-Cory, PCS-Allan, PCS-Patience Lake, PCS-Lanigan and IMC-Colonsay — extract the ore from the Patience Lake member. The mines in the southeast corner of Saskatchewan — IMC-K1 and K2, PCSRocanville — extract from the Esterhazy member, while IMC-Belle Plaine, near Regina, solution mines potassium chloride from both potash-bearing members.Ore from the Patience Lake member is a medium-grained mixture of sylvite and halite, with a KCl content of 36%, insolubles averaging up to 5.5%, and little or no carnallite.The ore from the Esterhazy member is a coarse-grained mixture of sylvite (KCl) and halite (NaCl) with a small amount of water insolubles, and some carnallite (a K-Mg chloride). Average run-of-mine grades are about 30% KCl."

Jan 1, 2003

By J. A. Haskin

The Engineering Department at Flin Flon has the following responsibilities: 1. Underground Surveying. 2. Open-Pit Surveying and Supervision of Blasting. 3. Mine Geology and Examination of Prospects. 4. Design of Plant Additions and Improvements. 5. Miscellaneous Field W ork, Reports, etc. The entire surface plant, as well as the underground workings, are located by co-ordinates based on a triangulation system covering an area approximately one mile long by one-half mile wide. The origin of this system and one end of the base-line is the southwest corner of Township 67, Range 29, west of the Principal Meridian. The bearing of the base-line was determined from the township boundary, which runs true north, so that all other bearings are almost astronomical. This is a great convenience when our surveys must be tied to mineral claims, rights-of-way, and land subdivisions. As the base-line extends across Flin Flon lake, its measurement across smooth ice was simple and accurate. The length, slightly over 1,600 feet, has been adjusted for the temperature and tension of the standard tapes used and checked sufficiently to ensure a maximum error of 1 : 15,000. Each angle was repeated ten times, but as no special refinements were used, errors of as much as four or five seconds are possible. The elevation of the origin of the triangulation system was approximately 1,050 feet above sea level. The use of this true elevation in our surveys would have resulted in negative elevations underground as soon as the mine reached a depth greater than 1,050 feet. To avoid this complication we therefore added 4,000 feet to this elevation. The collar of the Main shaft, for example, which is actually 1,072 feet above sea level, appears in our records as at elevation 5,072. Underground surveying, which follows standard practice, is done by two mine surveyors who share three helpers. The meridian is taken underground from two wires hung in either of the two vertical shafts.

Jan 1, 1935

By Gerry Roblesky

"IntroductionWestar Mining Ltd. is Canada's largest producer of metallurgical coal for the export market. It currently operates two mines, the Balmer Mine at Sparwood, British Columbia producing 6 000 000 tonnes per year and the Greenhills operation at Elkford, producing 2 100000 tonnes per year. Approximately 1600 people are employed between the two mines which operate independently but share common administrative services.Like most mining companies in Canada over the past three or four years, Westar has faced rising production costs along with flat or declining prices and demand for its products. In order to survive under these conditions it has become necessary to strive for decreased costs in any way possible. Over the past two years there has been a widespread introduction of microcomputers across the company. In order to satisfy increasing demand for accurate and pertinent information while at the same time increasing productivity, the microcomputer has become an invaluable tool.This paper describes some of the problems faced by a mine maintenance department in this operating climate and how they were solved with the help of a microcomputer. It also describes some of the problems that may be encountered both with equipment and people and recommends some ways that these might be minimized or avoided. Finally, an assessment of whether or not the move to microcomputers was a current and economical one, and a brief description of future plans and projects is given.The Maintenance OrganizationIn order to appreciate fully the role that microcomputers are playing within the Maintenance Department at Westar Mining, a little background on the organization and operating philosophies is in order. Most of the comments apply directly to the Balmer operations, however, the Greenhills operation is similar in concept.The mine maintenance organization operates on a fleet based concept with these departments reporting to the maintenance superintendent: haulage trucks, shovels and drills, loaders and Caterpillar equipment, maintenance services, and rebuild services.Each of these departments is headed by an assistant superintendent and is responsible for all maintenance on the equipment on the respective fleet. Shift foreman, planners, specialists and clerical staff are assigned to each fleet. A central engineering and administrative group consisting of one engineer and three clerical positions is responsible for maintenance engineering and centralized administrative services"

Jan 1, 1988

By T. Melfi, M. James

Attaining required mechanical properties in welds made using the double submerged arc welding (DSAW) process is difficult, and it is becoming more difficult as the strength level of the base materials continues to increase. Producing weld metal with adequate mechanical properties involves factors that are often overlooked and not taken into consideration. Not least amongst these problems is simply finding information to use in selecting the appropriate flux/wire combination. Most of the available data on flux/wire combinations provided by consumables manufacturers is generated using the multiple pass welding procedures required for classification per specifications such as AWS A5.17 and A5.23. This data really gives no insight into the properties that can be expected in a DSAW application. Also, base plate composition plays a very significant role because of the fact that base plate dilution can be as high as 70% in DSAW welds. This means that if any elements are present in the base metal that are deleterious to mechanical properties, they will also be present in significant quantities in the weld deposit. Some of these elements can decrease toughness and increase hardness (increased hardness is a concern if the pipe is intended for sour service). Some of these problems can be mitigated by proper selection of welding consumables. Selection of proper welding consumables means selecting an electrode that provides the appropriate alloying elements to obtain the desired level of impact toughness while also keeping the hardness within any specified limits. In order to attain the necessary impact toughness, selection of a flux with an appropriate composition (in terms of its basicity and its ability to control the nitrogen content of the weld deposit) is required. As with all welding processes, the mechanical properties of DSAW welds are also highly dependent on the welding procedures. This work clarifies how to select appropriate consumables to meet a given set of requirements, and also how to achieve the optimum mechanical properties from those consumables.

Jan 1, 2005

By Anoop Sattineni

Over the past decade the use of BIM in the AEC industry has grown several fold and with it the number of standards available for implementing BIM. The ?National BIM Standard? by buildSmart Alliance, the ?Contractor Guide to BIM? by the Associated General Contractors of America, the ?BIM Project Execution Planning Guide and Templates? from Penn State University, the ?BIM Roadmap? by the US Army Corps of Engineers are some of the several BIM guidelines that are currently available to the AEC industry practitioners. Some of these guidelines are as comprehensive as defining BIM and the associated taxonomy while others are meant to be used on an individual project basis. From a contractor?s perspective one of the key benefits of using BIM is for the purpose of collision detection and coordination. This research has found that currently available guidelines do not address these issues adequately. For instance, the currently available guidelines do not allow the subcontractor to quickly communicate issues such as naming conventions and color schemes within the model, to the general contractor. Consequently general contractors and sub-contractors find themselves making changes to their BIM deliverables based on each other?s abilities and levels of adoption, apart from reason?s stemming from use of different software platforms. This paper describes how a group of contractors and subcontractors from Atlanta and Birmingham in the United States came together to create and adopt a ?Coordination Guidelines for Virtual Design and Construction?. These guidelines were specifically created with the purpose of streamlining the construction coordination process using BIM. This paper describes how the guidelines created differ from other guidelines currently available in the industry.

Aug 1, 2013

By C. -S. Xie, J. -H. Kong

The microstructure and mechanical properties of X80 hot-rolled thick steel strips with a thickness of 17.5mm produced in Wuhan Iron & Steel Company (WISCO) are introduced in the paper. The steel strips as fabricated through proper thermomechanical processing (TMP)/ on-line accelerated cooling (OLAC) processing have shown high strength and toughness, low brittle transition temperature, good weldability, and high Shear Area (SA) percentage in Drop Weight Tear Test (DWTT). The microstructure of the steel strips is characterized with mainly acicular ferrite, and fine dispersed Martensitc-Austenite (M-A) phases. It is determined that the mechanical properties are improved due to the presence of the fine M-A phases and precipitates, which could be formed by reducing the finish rolling and coiling temperatures.

Jan 1, 2005

By M. Hajian Heidary

In this investigation, effect of pressure depth on the globulizations of AZ91 magnesium alloy was studied. Cylindrical samples of AZ91 alloy with 1 cm and 2cm in height and 2.5cm in diameter (H/D = 0.4 and 0.8) were prepared, then the samples were hot pressed at 10 and 30% strain at a constant temperature of 200°C; subsequently reheated at 555°C in different times. Results obtained from optical microscopy (OM) showed that the thickness of the samples and consequently, depth of strain affected regions have remarkable effect on the degree of globulization. In addition, it was found that at a constant strain and holding time, structure of thinner samples is more globular than thicker ones.

Jan 1, 2007

By Bennett McLaughlin

The Penna Shaft is the deepest single?lift shaft in North America. AGNICO-EAGLE started sinking the Penna shaft in 1995 with a hoisting plant capable of hoisting 1 800 tonnes per day from a 2 240-metre deep shaft. Exploration success at depth lead to the replacement of the existing double drum hoist by another double drum hoist capable of hoisting 7 000 tonnes per day. The use of another double drum hoist, instead of a Blair Multi-Rope winder, to hoist 24,5-tonne skips was only made possible by lowering the safety factor. This paper describes recent experiences at Penna and in South Africa, and examines the possibility of extending the double drum hoisting system to a depth of three kilometres.

May 1, 2003

By J. Fournier

A novel sol ? gel (SG) synthesis procedure utilizing varying ratios of glycine and ethylene glycol to total metal cations has been developed to create high purity nanometer sized La0.65Sr3.5MnO3 powders. X-ray powder diffraction (XRD), transmission and scanning electron microscopy (TEM, SEM), and dynamic light scattering (DLS) have confirmed that the crystallite sizes of such powders are ~ 20 nm, and the aggregate particle sizes vary between 100 to 300 nm. Mixing varying weight percents of SG LSM powders with commercially available Praxair LSM in a composite LSM/YSZ functionally graded cathode has been shown, through the use of electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), to exhibit enhanced oxygen reduction kinetics vs. at conventional cathode materials.

Jan 1, 2005

By D. M. Morrison

"The most important factor in Canadian mining is not the operating cost of current projects but the availability of capital for future projects. The future of mining at depth will be producing ore from the top of the orebody working downward with very effective, tightly controlled mining methods, i.e. either selective mining or bulk mining with well controlled dilution and fragmentation. The key characteristics of future mines will be smaller access excavations, more effective ground support, very precise blasting techniques and more efficient and reliable materials handling systems. Equipment will be smaller and designed for high efficiency and low maintenance, reducing both the capital and operating cost. This means there will be fewer scoops, more continuous mucking machines and conveyor belts, both lateral and vertical.Orepass failures have become accepted and the resultant redevelopment and retramming has become common. The capital investment in so-called permanent ore passes and crusher stations becomes questionable, particularly when crushers are only necessary for less than 10% of the ore going through the system. The best way to solve the chronic instability of ore passes is, as with all of the stability problems at depth, by reducing the excavation size rather than increasing ground support. Smaller access drifts would reduce the capital cost and increase the rate of development as well as reduce the amount of waste to be handled, reducing the ground support and the ventilation requirements. Large drifts and ore passes are essential only for the equipment needed to handle large pieces of ore and the productivity of scoops is very expensive when the requirements for ventilation and large access drifts are taken into account. The key issue is the fragmentation generated by primary blasting.The future of mining in Canada will depend on simple and robust technology geared to the environment in which it will have to operate. Its survival will depend on some-thing much more fundamental and difficult to accomplish than a technological advance — it will require a dramatic change in the way the mining process is managed, how work is organized, how effort is rewarded and how costs are measured — a complete change in mind-set."

Jan 1, 1996

By A. J. Rigby

Anode vessels are often relined with refractory every one to two years and a typical reline time can take between 16-20 days. Modem refractory designs using dense, corrosion resistant brick applied directly to the vessel shell in the high wear areas around and above the tuyeres and at the slagline can yield a lining life of up to 4-5 years before a complete reline is necessary. Installation methods using brick delivery on roller conveyors through an endwall access port and complete anchoring of the brick to allow for lining self-support can take days off the installation time. It is possible, therefore, to reduce the refractory relining period by 50% and increase lining life by 100% compared to typical anode repair schemes. Cu2007

Jan 1, 2007

By C. Kuehmann, B. Tufts

QuesTek Innovations has applied its Materials by Design® methodology to computationally design a new ultra high-strength corrosion resistant steel. Ferriurn® S53 eliminates the need for toxic cadmium coatings currently used on conventional steels in landing gear systems. S53 has the strength of 300M steel, and corrosion resistance similar to 15-5PH stainless steel. S53's corrosion resistance improves stress corrosion cracking resistance and reduces susceptibility to hydrogen embrittlement, improving component reliability and providing an opportunity for extended overhaul and repair intervals. Ultimate tensile stress is 1965 to 2000MPa. S53 was designed to be mechanically equivalent to 300M, with the key addition of intrinsic corrosion resistance. Alloy design, microstructural characterization, and mechanical properties are discussed herein.

Jan 1, 2006

By J. Fournier

A novel sol ? gel (SG) synthesis procedure utilizing varying ratios of glycine and ethylene glycol to total metal cations has been developed to create high purity nanometer sized La0.65Sr3.5MnO3 powders. X-ray powder diffraction (XRD), transmission and scanning electron microscopy (TEM, SEM), and dynamic light scattering (DLS) have confirmed that the crystallite sizes of such powders are ~ 20 nm, and the aggregate particle sizes vary between 100 to 300 nm. Mixing varying weight percents of SG LSM powders with commercially available Praxair LSM in a composite LSM/YSZ functionally graded cathode has been shown, through the use of electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), to exhibit enhanced oxygen reduction kinetics vs. at conventional cathode materials.

Jan 1, 2005

By E. T. W. Bailey

A HISTOR Y of the development and application of instruments, from the simplest U gauge to a modern indicating recording controller, would contain many interesting accounts of difficulties experienced and over-come. Important as is the history of development to any branch of science, this phase will, of necessity, have to be omitted from this paper and remarks confined to the results from the use of instruments in their present form. The steel industry bas, in the past decade, become increasingly instrument minded. More than ever, economy and adherence to doser specifications are demanded, and any tool that will aid in attaining these objectives by intelligent application and use finds a ready acceptance. The open-hearth furnace bas offered a field for instruments which is different from almost any other and one in which even a small percentage saved in operating costs may represent a considerable sum. Nevertheless, this department of the steel industry has been more cautions than most others in accepting the benefits which automatic control bas given on many other types of industrial furnaces, and one is puzzled why open hearths have not more generally benefited by the application of controlling instruments. The furnace operator bas to adjust the same three main valves that control fuel, combustion air, and stack draft as on most other furnaces, with the additional regulation of reversing the furnace. He is just as aware of the importance of proper draft control and correct air volume to burn most economically the applied fuel as any good boiler-plant engineer. What, then, are the special conditions that pertain to the open-hearth furnace?

Jan 1, 1939

By Daniel Hodouin, Bruno Girard, Claude Bazin

"Mineral processing and smelting operations have the reputation of being complex processes. Process operators of these unit operations have acquired from experience and basic training a superficial understanding of the relationships between process output and manipulated variables. This understanding, which is a very valuable know-how for process control and optimization as well as for operator training, is however difficult to extract. This paper describes a time series based approach that can be used to extract this know-how, which can subsequently be used for operator training. The method is illustrated with an example taken from a smelting process.IntroductionThe emergence of Total Quality Management and Statistical Process Control philosophies in the North American industry (Brown, 1991 ), as well as the increasing popularity of the IS0- 900x standard accreditation, provide a strong incentive to review the training procedures for plant operators. The importance of employees training is acknowledged in two of the 14 points of Deming's road to quality (Deming, 1982) as well as by control engineering consultants (Hendricks et al., 1994). However guidelines for the operation of industrial processes are often transferred from an operator to another one with allowance for flexible interpretation of many operating rules. Such transfer is typical of complex industrial processes to which particulate processes of ore dressing and extractive metallurgy belong.Capturing the knowledge of experienced operators is often a difficult task. Cognition engineers are able to extract this knowledge and transfer it into rules that ultimately are implemented into expert systems. Cognition engineers are however not always available and plant supervisors may prefer to keep training as an internal liability. Another difficulty through interviewing of the process operator is its lack of willingness to transfer what he has learned by hard working to other people, whose ultimate goals are to develop computerized applications that may replace him in a near future, or reduce its importance in the production line.This paper shows that time series can be advantageously used to capture the average process understanding of plant operators and to help reviewing training procedures. The method s illustrated with data collected during normal operation of electric arc furnaces and it is shown how the approach has led to a fruitful discussion between process engineers and operators that ultimately provided savings of more that $200,000 per year per furnace. There are 9 furnaces in the studied foundry. Such savings are not the results of application of advanced control strategies nor of ""miracle press button software», but of an improve awareness by engineers and operators of the importance of properly defining the operating procedures to control a process."

Jan 1, 1996

By Ali Bunjaku, Lauri Pesonen, Hannu Johto

It is well known that there are many ways to process copper concentrates into copper anodes using the pyrometallurgical route. All modern copper smelting technologies are fundamentally energy efficient and environmentally safe options, and therefore choosing one depends on the desired capacity range, feed impurity levels, plant location, flexibility needs, overall energy use, and of course smelter economics in both the short and long term. This paper focuses on comparing different solutions which have potentially the lowest variable opex (operational expense), meaning in practice finding out which technology offers the best chances for profit maximization under certain scenarios. For the comparison, we chose to have a closer look at Outotec Flash Smelting (FSF) – Peirce-Smith Converting (PSC), Outotec Flash Smelting (FSF) – Outotec- Kennecott Flash Converting (FCF), Outotec Ausmelt TSL Smelting (ASF) - Peirce-Smith Converting (PSC), Outotec Ausmelt TSL Smelting (ASF) - Outotec Ausmelt TSL Converting (ACF), Mitsubishi Smelting Process (MIT), Bottom Blowing Reactor (BBR) – Bottom Blowing Continuous Converting (BCC), and Side Blowing Furnace (SBF) - Top Blowing Converting (TBC) since these seem to be the main state-of-art technologies now being applied in many recent copper smelter projects around the world. The work was carried out by modelling each smelting route by using the new HSC SIM 9 simulation software and applying operation time, energy, and consumables consumption numbers for each unit process and stream. Combined with cost data, the exercise produced a rich set of information which will be shown in detail for each area per scenario. The authors’ goal here was to provide a fair comparison where each technology can be evaluated from various perspectives such as electricity use or refractory consumption. INTRODUCTION Copper can be produced either pyrometallurgically or hydrometallurgically. The hydrometallurgical route is used only for a limited amount of the world’s copper production (~20%) and is normally only considered in connection with in-situ leaching of copper ores. On the other hand, most of the copper extraction from Cu-Fe-S minerals is pyrometallurgical (~80%) (Schlesinger 2011, ICSG 2017). Thus, several different processes can be applied for copper production, including the following state-of-the-art technologies: Outotec Flash Smelting (FSF) – Outotec-Kennecott Flash Converting (FCF) Outotec Flash Smelting (FSF) – Peirce-Smith Converting (PSC) Outotec Ausmelt TSL Smelting (ASF) - Peirce-Smith Converting (PSC) Outotec Ausmelt TSL Smelting (ASF) - Outotec Ausmelt TSL Converting (ACF) Mitsubishi Smelting Process (MIT) Bottom Blowing Reactor (BBR) – Bottom Blowing Continuous Converting (BCC) Side Blowing Furnace (SBF) - Top Blowing Converting (TBC)

Jan 1, 2019

By Daniel Hodouin, Mélanie Proulx, Claude Bazin

"Collector and frother are commonly used to induce the floatability of valuable minerals in flotation plants. These reagents are usually distributed down a flotation bank or sometimes added in a single location at the top of the bank. A review of the literature and some experimental results obtained from laboratory and full scale trials indicate that the way flotation reagents are distributed down a flotation bank may influence the flotation response of coarse particles. The paper summarizes these observations which show that the distribution of reagents is a potential tuning variable for process optimization.IntroductionFlotation is in many cases the only way to concentrate sulphide and some oxide minerals. Flotation is a concentration process that uses particle surface composition to induce the selectivity by mean of hydrophobic reagents. The influence of particle size on flotation was firstly analyzed in the 50's1·2 and intensively investigated in the 70's, early 80's and 90's3-18. Most of the observed results show the existence of an optimum flotation size range9 whose recovery is not significantly influenced by a reduction of collector dosage""18. This result brought the idea of using a small portion of the total collector dosage at the top of a rougher bank and to distribute the remaining through the end of the bank to ensure sufficient collection of the coarse particles that need more hydrophobic coverage to attach to air bubbles and be lifted to the surface.This paper discusses the idea of using the distribution of reagents down a flotation bank to tune the operation of the process. Unlike the literature on the effect of reagents (collectors, frother...) dosage that is dense, little attention has been put on the distribution of reagents in a flotation bank. Although research on this subject has not been pushed very far, some operators have recognized the potential of a strategic addition of reagents down a flotation bank19. Except for a few exceptions, the proportions of the reagents to be distributed down a flotation bank are decided according to operator's experience instead of process analysis in relationships with particle size. This paper recalls observations made by different researchers that lead to the idea of using the distribution of reagents as a tuning variable for the flotation process. The paper does not present a detailed analysis or optimization scheme for tuning the distribution of reagents, but analyzes some plant and laboratory results with a view toward the development of a testing methodology and ultimately a validation or rejection of the idea."

Jan 1, 1998

By M. Amsden

"Since the computer program is far from complete this must be only a brief progress report on the computerization of flotation metallurgy at the Ecstall concentrator at Timmins.Ecstall is currently treating about 10,000 tons per day of two different ore types. One is a low sulphide copper-zinc ore, the other is a high sulphide lead-zinc-silver ore. The concentrator is divided into three individual grinding and flotation circuits. In effect there are three mills under one roof. Normally there are two circuits on copper-zinc ore and oneone lead-zinc-silver ore. At this point in time one of the copper-zinc circuits is under computerized metallurgy control.The first step in this control is the use of an ARL on-stream x-ray analyzer, coupled with a Honeywell 21 computer which types out assays and recoveries for each individual circuit. Our approach to a computer program was to keep it simple. The program was written to coincide as closely as possible to what an operator would do in the performance of his duties based on the in-formation he was getting from the x-ray analyser read-out. Initially, computer control was put on just the copper circuit of the ""A"" Division, controlling the collector addition at three points in the circuit; primary, secondary, and scavengers. The control was based on recoveries and the grade of the copper concentrate. Targets like 95% recovery and 24% copper concentrate grades that it was felt the circuit could achieve were set to start with. It quickly became apparent that this alone was not enough because if on a certain ore the best recovery that could be made was only 94.9% the computer kept calling for more reagents until the circuit was completely out of control. On another ore it might have been quite possible to get 96% recovery but when the set point of 95% was reached the computer stopped trying for any more. To overcome this problem a very simple optimum seeking program was devised by one of the Ecstall staff and it has worked very satisfactorily since being put into use in July 1970.In the copper float only the two collectors R-208 and the xanthate R-317 are under computer control. The addition of frother and depressant is left to the operator. The flotation cells have automatic level controls which can be adjusted by the operator. pH is controlled automatically through a lime loop-sensor arrangement."

Jan 1, 1971