Search Documents

Overview ?Oil Sands Background ?Water Use in Surface Mining ?Tailings Disposal ?Water Balance for Surface Mining ?Implications of Emerging Regulations ?Water Management Framework ?Tailings Performance Criteria (Directive 074)

May 1, 2009

By Richard Klimpel

"Over the last 15 years, there has been a number of plant scale sulfide mineral flotation tests organized by this author specifically aimed at understanding how flotation rate varies with reagent type and dosage. With regard to the Interaction of collector dosage, particle size, and frother type, the eight specific trends listed in the paper (Illustrated with data from two specific case studies) are qualitatively the same for almost all plants studied in some depth. The Interaction of flotation rate K and equilibrium (Infinite time) recovery R in the plant has been denoted as the R/K trade-off. The effect of collector dosage on the rate of flotation of specific particle size intervals is particularly interesting and once understood, is quite useful In understanding how industrial flotation plants respond to changing reagent type and dosage. The location and magnitude of the R/K trade-off can be different for various ores and various plant configurations, but the RIK trade-off is almost always present. The purpose of this paper is to clearly describe and illustrate the nature of this very Important flotation system Interaction so that operating engineers have a starting reference point for beginning successful plant Improvement studiesIntroductionIt is well recognized by industrial froth flotation plant operators that improving existing sulfide circuit performance is often difficult due to the self-compensating systems nature of the froth flotation system, e.g. Klimpel (1988, 1989, 1995). Extensive plant testing with existing and new reagents by this author throughout the world has clearly shown that one of the more important self-compensating mechanisms is the Interaction between collector dosage, frother type, and particle size. The term self-compensation in flotation simply means that as the plant operator consistently changes one parameter in the same direction, the nature of the froth flotation system Is such that the circuit will eventually begin to resist this controlled parameter change by automatic (uncontrolled) changes In other parameters and the overall circuit performance will go through a maximum or minimum (hence causing the operator to stop the parameter change)."

Jan 1, 1997

By J. Maheu

Heap leaching is an old technique for the recovery of copper, but a fairly new technique for the recovery of gold.The paper outlines the equipment required for the establishment of heap leaching test facilities and the procedure required to insure meaningful results. Sampling methods, the metal balance, carbon adsorption and stripping and safety procedures are discussed in broad outline.

Jan 1, 1982

By D. J. Hutchinson, M. Lato, M. Diederichs

Light Detection and Ranging (LiDAR)-based applications for geomechanical purposes have recently proven to be a highly reliable and accurate form of remote analysis and documentation. The ability to remotely collect, process and evaluate rockmasses for structural geomechanical applications has benefits ranging from safety to efficiency, and provides a permanent record that can be assessed before and after an excavation has been completed. With the collaboration of Queen’s University and Rio Tinto, the Iron Ore Company of Canada (IOC) mines in Labrador City, Newfoundland and Labrador, evaluated the practical application of the I-Site 4400 LiDAR equipment, in conjunction with the Vulcan geotechnical module for geomechanical purposes. The project provided a comparative analysis between conventional hand-mapping and digital analysis. The analysis indicates that digital mapping could be employed as an active tool within the general geotechnical workflow, where results would be used in pit wall and rockmass support designs. As well, the field work enabled the generation of effective operational guidelines and protocols to maximize scanning efficiency.

Jan 1, 2009

By M. Rebolledo, N. Mora, G. Zarate

For decades, the mining industry has been focussed to find an efficient and economically attractive process for the leaching of chalcopyrite. Jetti Resources has developed a novel hydrometallurgical alternative to extract metals of value from mineral ores that the mining industry has struggled to process. Jetti’s catalytic technology, whilst being especially advantaged for extracting copper from low-grade and highly refractory minerals, such as chalcopyrite, seamlessly integrates with existing heap leaching methods and downstream processing operations. The technology uses a catalyst which weakens the metal-sulfide bond in the crystalline structure of the chalcopyrite mineral and alters the structure of the passivation layer allowing the leaching process to continue. Metallurgical test work was conducted to examine the effect of ore variability, in terms of grade and copper deportment. The results presented in this study highlight the amenability of the technology and demonstrate that it is possible to enhance leaching performance of copper primary sulfides over a wide range of copper grades, from 0.1 to 2.2%. Further, it is concluded that despite the copper grade, the tests with increasing chalcopyrite content render copper recoveries up to 4 times higher compared to the tests under non-catalyzed conditions. Jetti’s catalytic technology is currently being evaluated at larger scales, namely a commercial dump leach operation and 50-tonne crib tests. The results obtained thus far are compared to the results from conventional sulfide heap leaching tests. INTRODUCTION For decades, the mining industry has been focussed to find an efficient and economically attractive process for the leaching of chalcopyrite. Chalcopyrite (CuFeS2) is the most abundant and recalcitrant of the copper sulfides (Singer, 2017). Owing to its abundance and economic importance, it is the most demandable natural source for copper worldwide. In fact, the projected demand for copper is further expected to rise much higher beyond the current demand by the year 2020 (Panda et al., 2015). Therefore, it becomes imperative to find low intensity hydrometallurgical technologies for the extraction of copper from chalcopyrite in ores of such low-grades that are un-economic to concentrate and to augment the supply by extracting copper from ores with complex mineralogy that cannot be concentrated (Watling, 2013).

Jan 1, 2019

By K. M. Ed

AN explosive is a solid or liquid substance which, when fired by some means, changes into a gaseous product occupying a volume very much greater than its original volume. The great speed at which this change takes place causes the explosive to exert a sudden blow on adjacent material. It is this action which is effective in blasting operations when the explosive, confined in a shot-hole, is fired. All explosives are similar in one respect, in that the change into the gaseous state is accompanied by the production of hot gases or flame. This results from the rapid combustion of the solid or liquid ingredients. Ex-plosives differ greatly, however, in the speed at which the reaction takes place. Black blasting powder, for instance, reacts comparatively slowly, hence the flame persists for an appreciable length of time. High explosives, on the other hand, react much more quickly; consequently, the flame is of much shorter duration. In 'closed-light' or 'gaseous' coal mines, the use of ordinary explosives is generally prohibited, due to their inherent ability to ignite gas or coal-dust by reason of the flame which they produce when fired. For instance, black blasting powder, which produces a flame of long duration, is not ordinarily considered safe to use in such mines; neither are ordinary dynamites, as their flames, while shorter than that of black blasting powder are, nevertheless, of sufficient temperature and duration to cause ignition of fire-damp or coal-dust. For this reason, specially formulated high explosives, called 'permitted' explosives, should invariably be used in such mines.

Jan 1, 1940

By A. J. Monhemius

"This paper reviews the history of modern iron-control processes in hydrometallurgy. Attention is paid to processes developed in the electrolytic zinc industry for removal of iron from zinc sulfate leach liquors and the problems faced by the industry in the safe disposal of the iron residues produced by these processes. Past lessons learned are projected onto current efforts to develop hydrometallurgical processes for treatment of copper sulfide concentrates. It is argued that any attempt to create a “hydrometallurgical copper smelter” will fail, unless methods are developed that can recover iron in a form that can be directly used by the steel or pigment industries.RÉSUMÉ Cet article passe en revue l’histoire des procédés modernes de contrôle du fer en hydrométallurgie. Il accordera une attention particulière aux procédés développés dans l’industrie du zinc électrolytique pour l’élimination du fer dans les liqueurs lixiviantes de sulfate de zinc anhydre, ainsi qu’aux problèmes rencontrés par l’industrie en termes d’élimination sans danger des résidus ferreux générés par ces procédés. En projetant les leçons tirées du passé sur les efforts actuels, on pourra développer des procédés hydrométallurgiques pour le traitement de concentrés de sulfure de cuivre. Beaucoup prétendent que toute tentative de créer une « fonderie de cuivre hydrométallurgique » échouera à moins de développer des méthodes permettant de récupérer le fer sous une forme pouvant directement être utilisée par les industries sidérurgique ou des pigmentsINTRODUCTIONThis paper resulted from an invitation to the author from the CIM’s Historical Metallurgy Committee to give a presentation on the early developments of iron control in hydrometallurgy. This was to take the form of a plenary lecture at the 4th Symposium on Iron Control in Hydrometallurgy, which formed part of the 28th International Mineral Processing Congress, held in Quebec City in September 2016.I was naturally flattered that the invitation was to give the lecture at an IMPC, the prestigious conference series that has been held since the 1950s. That this particular IMPC was to include the 4th Symposium on Iron Control in Hydrometallurgy, a conference series held only every 10 years, made the invitation even more appealing and appropriate. This was because I had been co-chairman of the First Symposium on Iron Control, together with my erstwhile colleague, John Dutrizac, which was held 30 years ago in Toronto."

Jan 1, 2017

By Ronald E. Hamilton

"An attempt to review the recent literature on comminution reveals at once that the subject has many ramifications and that the applications are so diverse that there are very few general statements which can be made.It. seems reasonable to start classification on the basis of size of material as Input to the comminution process. However, we find that this can only be done in a very imprecise manner.The initial step of breaking rock from its natural state of very large pieces in geological formations into sizes suitable for processing is accomplished by blasting. This step in the process has not been ex-amined in this project except to note that great changes have been made during the last decade or so in the explosives used, and in the method of handling them. We should determine what effect changes in mining methods can have on the need for crushing.The second step in the process is usually primary crushing, performed by gyratory or jaw crushers. The largest chunk which can be fed to a jaw crusher depends on the size of the machine, and should be larger than the largest fragment produced in the miring process. It is obvious that the larger the crusher, the less care required in mining to en¬sure the absence of rocks too large to be crushed. The optimum size of crusher to minimize overall cost of mining and reduction is not at all obvious, and no information on this point has come to light in this investigation.It is rather generally accepted that size reduction is most efficiently done in small stages, and that different machines have different opti¬mum size ranges of feed. For example, crushers are preferred for sizes above about 1"", rod mills for the range between 1"" and 0.1"", ball mills are preferred from 0.1""down to perhaps 10 microns, and vibratory mills, or jet mills, below 10 microns."

Jan 1, 1976

By A. Dave Mackintosh

In 2001, at the CIM AGM in Quebec, a paper discussing poor ground conditions in a newly opened area at Agrium?s Vanscoy Potash Operation?s, suggested load transfer around old workings as a possible reason for the early room failure. High closure rates are expected in deeper regions however the rapid failure of walls immediately behind the face resulted in protective guards being mounted on and behind the borer. The high closure and early rib failure continued well past any reasonable distance to be explained by load transfer around old workings and investigations continued into possible reasons other than simply depth. Detailed investigations into the mineralogy and crystal fabric of the ore zone provided one possibility, which combined with a changed borer cutting profile are now believed to have contributed greatly to the poor conditions.

Apr 1, 2005

By A. C. Ross

"The paper will deal with non-destructive testing in general, and its advantages to those responsible for the maintenance of wire rope. An outline of the main features of the M.D. 6 Defectograph will be given, and the method of operation and results obtained will be described.The instrument will accommodate ropes at 7 /16-to 2 %-inch diameter at reasonable speeds, and is capable of detecting the most minute defects in even the largest-diameter wire ropes."

Jan 1, 1969

By E. Amini

"While methods exist to allow the simulation and optimization of existing flotation operations, there is a deficit in the ability to predict the performance of a new ore type pre-processing. A laboratory scale batch flotation testing methodology has been developed to assess the flotation potential of ores (known as the JK Floatability Index or JKFI). Previous work conducted by Alexander and Collins (2008) showed that the test could be used to predict full scale results in base metal ores. In this work, JKFI tests were applied to three different types of ore and one blend from a greenfields gold deposit to show the test applicability to flotation of precious metals. The results from the JKFI test on one ore type were then used to predict the response of all ore types (including the blend). To validate the predicted kinetic parameters, a comprehensive survey was performed on a pilot plant where each of ore types was processed in the circuit. An acceptable agreement was found between the experimental recoveries and predicted recoveries which indicate the potential of this method for use in predicting the flotation response of an ore.INTRODUCTIONOver 100 years, flotation has been considered an efficient method to concentrate different types of sulphide and oxide minerals and coal. Thus, numerous research studies have been undertaken to find an appropriate model to predict the behaviour of particles in flotation circuits (Barnwal et. al., 2006; Bascur and Herbst, 1983; Cecile and Villeneuve, 1991; Deng et. al., 1996; Zheng et. al., 2006). Most methods are based on the ore flotation response in an industrial plant which is expensive and time consuming to characterise. It is difficult to reliably predict flotation response for new types of ores in industrial scale plants.The floatability component modelling (FCM) approach, developed within the Australian Minerals Industry Research Association (AMIRA) P9 project, has been used to derive models of operating flotation plants for the purpose of simulation and optimisation (Alexander and Morrison, 1998; Alexander et. al., 2000; Varadi, 2006). This approach has been applied at a large number of operating sites treating a wide variety of ores. The approach requires metallurgical surveys to be undertaken in conjunction with batch flotation tests and cell characterisation. This allows ore and machine parameters to be derived, which are then used in the P9 Flotation Model. The development of a FCM generally requires a large commitment of resources and time. While there has been significant support of this approach in industry, the FCM approach is limited to ores already being processed (Runge, 2004; Wightman, 2006)."

Jan 1, 2009

By J. R. Welsh, D. J. Palmer, O. M. G. Newman

"The use of calcine for selective zinc precipitation requires specialist knowledge to achieve satisfactory flowsheet design. Calcine from the bed of a fluid roaster is preferred, and factors such as the size distribution of ground calcine, the stoichiometric ratio of the calcine precipitant to the initial dissolved zinc concentration and the moisture content of the resultant filter cake are parameters which require critical attention. Extensive testing in a fully-integrated electrolytic zinc plant pilot plant has demonstrated that properly designed selective zinc precipitation plants using calcine as the precipitant are reliable operating units.The advantages of using calcine instead of limestone for selective zinc precipitation include a decreased cost of reagents, as well as avoiding the formation of by-product gypsum.Process simulation modelling has demonstrated that the use of calcine in this context has widespread application in the design of zinc plants with superior impurity and water balance control characteristics. A particularly powerful approach involves closed circuit washing. In this mode, filtrate from the selective zinc precipitation step is used to wash a zinc plant residue such as jarosite, and the resulting filtrate is returned to the selective zinc precipitation section. IntroductionThe Selective Zinc Precipitation (SZP) Process, developed and patented by the Electrolytic Zinc Company of Australasia Limited (EZ) may be used to achieve simultaneously, water balance and impurity control in an electrolytic zinc plantO,2). Impurities which may be controlled by the SZP process include chlorine, magnesium, manganese, potassium and sodium.In the SZP process, basic zinc sulphate is precipitated from a zinc sulphate solution by either limestone, lime or a compound containing zinc oxide, usually calcined zinc sulphide concentrate (calcine) or alternatively zinc oxide fume .The solids containing basic zinc sulphate are separated, typically, by filtration and returned to the zinc plant circuit as a neutralizing agent. The zinc depleted solution can either be discarded, or used to wash residues, thereby achieving water balance and impurity control (Fig. I)."

Jan 1, 1988

In order to maintain a production rate of 6,000 tonnes per day from underground at the Williams Operating Corporation, two independent mining areas were required which created a long narrow sill pillar between them. During initial mining of the sill pillar there were a number of significant ground falls [LeBlanc and Murdoch, 2000] and in March 1999, with no active mining ongoing in the sill pillar area, a rockburst of magnitude 3.0 Nuttli occurred. Extensive ground support was designed and installed to withstand events of similar magnitude [Bawden and Jones, 2002]. A mine wide microseismic system was installed to monitor mine induced seismic behaviour over the entire mine. The area most directly affected by the 1999 rockburst was rehabilitated using a highly ductile support design. Along with microseismic instrumentation, the areas were instrumented using conventional SMART Cables and SMART MPBX?s. Subsequent to this, the area was impacted by a large number of high magnitude seismic events [magnitudes between 1.7 and 3.5 Nuttli]. The ground support performed very well during these events, providing confidence in the mine?s ability to control the ground under severe rockburst conditions. Analyses of microseismic and conventional instrumentation, combined with numerical analyses of sequence alternatives, were used to develop an optimal mining strategy for the sill pillar area. The selected strategy involved utilization of instrumentation data and calibrated model results to analyze yield zones in the sill. The analyzed ?yielded? zones were assessed to be low seismic risk. Initial mining in the sill was then concentrated in these low risk areas, with the objective of further concentrating stress into the remaining seismically active area, in order to induce ultimate failure of the sill. Continuing large magnitude seismicity and resulting damage in the remaining ?high seismic risk? area, led to abandoning a second portion of the footwall access and the strategic decision to extract a stope near the centre of this zone in order to force final failure of the sill pillar. During execution of this plan two large magnitude seismic events occurred resulting in destressing and final failure of the remaining sill pillar. The paper provides a detailed description of this ?strategic mine sequence driven self-destressing process? and the implications to final extraction planning in this area of the mine.

Apr 1, 2005

By François Robichaud

"The Laronde mill has been in operation since 1988. Actual milling rate ranges from 7,000 to 8,500 mtpd. Laronde uses SAG/ball mill grinding followed by copper and zinc flotation circuits. A cyanidation/Merrill-Crowe process recovers the remaining gold and silver in the flotation tails.In 1999, the carbon in pulp circuit was replaced by a Merrill-Crowe circuit in order to cope with a much higher ratio of silver/gold associated with the discovery of the Penna shaft. Marine type diatomaceous earth was used as filter aid in both clarifier pressure leaf filters and recessed pressure filter presses from 1999 to 2005. In 2005, this filter aid was gradually replaced by alpha-cellulose after several laboratory and plant filtration trials. The selected cellulose is considered to be much less sensitive to parameters such as pH and reagent concentration and have increased clarifier and filter press filtration performance. Also, since cellulose is exothermic, replacing diatomaceous earth with cellulose as filter aid in the filter presses has increased calcining and oxidation rates in the calcining ovens since cellulose is exothermic. Finally, better calcining conditions have resulted in energy and reagent savings at the arc furnaces.This paper describes how the filter aid replacement has contributed to increasing productivity and Net Smelter Return of the refinery while reducing worker’s hazards and operating cost.INTRODUCTIONAll Merrill-Crowe circuits in the world are operated with filter aids. For years, the market for precoat filter aid has been dominated by mineral filter aids such as diatomite and perlite. Flowsheet and equipment selection at the Laronde refinery were performed in the late nineties. At that time, some key parameters of the design criteria had clearly identified marine type diatomaceous earth (DE) as the most successful filter aid. Parameters such as reagent cost and availability, clarity of the filtrate solution and good historical filtration performance in other concentrators had designated DE as the best suited filter aid. Pregnant solution processed in the refinery from its start-up through 2001 was fairly stable in flow rate and reasonable in terms of impurity content (cationic and anionic compounds)."

Jan 1, 2007

By J. E. Nesset

"I had been requested earlier this year by MetSoc, our sister society of CIM, to contribute a chapter on technical developments in Canadian mineral processing over the past 50 years to their 50th Anniversary volume. Accepting the challenge of assembling such a chapter seemed at first a reasonably straightforward task, until one realises that the list of contributions by Canadians to mineral processing over this period has been more than just significant. It turns out to have been an extraordinarily fertile time for innovation and impact for Canadian-based technology. The list is necessarily a subjective one, however I had no trouble identifying twenty technology developments that are clearly outstanding, and there are undoubtedly others. As much as possible, I approached the individuals themselves who played key roles in each technology and asked that they tell the “story”. Without exception, all who were invited accepted eagerly and delivered more than I had hoped for. The technologies have been grouped into those that are truly Canadian innovations, such as the Knelson gravity concentrator and the McGill gas dispersion sensors in flotation, and technologies where Canadians and Canada played a very significant role in their success and implementation, such as AG/SAG grinding and ion-beam surface analysis. Also included are what may be termed technology transfer initiatives and institutions that have risen to a world class level, such as SGS Lakefield and the Canadian Mineral Processors Society of CIM. The challenge is now for the coming generation to continue this record of innovation and contribution to the industry, and that includes the (mostly) Canadian mining and metallurgical companies who have taken the longer term view and supported many of these initiatives, through their critical early years, with both financing and project sites for these ideas. Let us hope that the current trend of mining company globalization will not dampen their enthusiasm to participate. This plenary presentation will highlight many of these technologies, the individuals behind them, and their significance to the mineral processing industry."

Jan 1, 2012

By Lee Nichols

Convergent Bitumen Recovery Context of discussion It should be noted that the CBR process is a conceptual bitumen recovery feed methodology, designed to provide supplemental bitumen to the oil sand operations of Northern Alberta. To date the following have beencompleted. ?Bench Scale testing. ?Peer group brainstorming. ?Energy Balance ?Confidentiality agreements have been signed with several companies Discussions are ongoing with industry and although conceptual atthis stage the process holds significant promise.

May 1, 2007

By L. Hanschar, C. Bwalya, E. Mokola, K. Musonda, A. Makayi

This paper describes the installation, commissioning and operation of porous plugs featuring nitrogen gas purging in both Anode Furnaces at the Kansanshi Copper Smelter (KCS), a greenfield copper smelter which commenced operation in March 2015. The decision to install porous plugs was taken in November 2016 and the facilities were successfully commissioned on both anode furnaces in October 2017. The project was successful and has demonstrated the following process improvements: 12.2% reduction in main burner fuel consumption Larger average charge size, due to fewer accretions; 17 minute decrease in average refining cycle times Improvements in slag skimming operations Improved casting rates INTRODUCTION Porous plugs The application of porous plug technology in copper smelter anode furnaces is well established around the world. Vukovic and Gamweger (2017) and Wallner (2004) noted that the stirring and mixing action induced by the injection of inert nitrogen gas into the molten copper via porous plugs has potential benefits in the following areas: Homogenization of the temperature and composition of the molten copper resulting in Reduced fuel consumption Less tendency to overheat slag (reduced risk of refractory attack) Less slag produced with a lower degree of oxidation (lower rate of refractory wear) Less tendency for buildups to form Improved environmental performance (produce low sulphur blister at Peirce Smith converters) Elimination of buildups inside the furnace and potential for larger charges per cycle Reduced processing times and potential for shorter cycle times More efficient skimming of anode slag Shorter skimming time Less copper carry over to Peirce Smith converters Very little slag remaining in the furnace (reduced potential for buildups to form)

Jan 1, 2019

By R. A. Brown

RIGHT NOW the Canadian oil business is suffering from growing pains brought on by developments outside our borders. I would like, therefore, to place our industry in perspective for you in two ways. I would like first to describe it briefly and let you see it in relation to the world oil industry. Then I would like to bring it back and place it into perspective against a strictly Canadian background. Naturally, in such a discussion, it is necessary to use a certain amount of statistical material. I'll endeavour, however, to keep it to a minimum. Eleven years ago, before the discovery of Leduc, Alberta could boast of having 21,000,000 barrels of crude oil reserves. Five years ago we had 1,810,000,000 barrels. At year end, 1957, our remaining recoverable reserves totalled more than 3,000,000,000 barrels. In 1957, our potential production in Alberta reached an all-time high of 756,000 barrels a day. Unfortunately, our actual average daily production dropped from 393,000 barrels per day in 1956 to 376,000 barrels per day in 1957. And in 1958, to date, it has dropped sharply to around 300,000 barrels per day.

Jan 1, 1958

By V I. McCallum

In 1954, Falconbridge Nickel Mines Limited began the program of deepening the Falconbridge mine workings for 2,000 feet below the bottom, or 4025, level in order to provide twelve new levels for production. Involved in this program were a production-sized internal shaft, .crushing, pumping and hoisting installations, the integration of the new shaft operations with those of existing shafts, and considerations of ventilation requirements and ground support at depth. This paper describes the major items of equipment, and the depth development of No. 9 shaft as a whole, and also emphasize the planning phases of the program. The factors involved and reasons for the equipment and layouts chosen are given. Introduction and History THIS paper describes the planning and development of that portion of the Falconbridge mine between the 4025 and 6050 mining levels. This mine, the oldest of several being operated by Falcon-bridge Nickel Mines Limited in the Sudbury district, has been a continuous producer for over thirty years.

Jan 1, 1964

By Edmund C. Bovey

"AS I begin my remarks this morning, please let me say how honoured and gratified I was to receive your invitation to address you here during your deliberations in historic Quebec City. The high esteem in which your Institute is held is reflected in the respect and deference accorded to it by industry across Canada. I feel privileged to be here with you today.I would like to discuss with you some applications of natural gas in the mining industry and suggest to you, in closing, some possible avenues of future development.Natural gas first became avail-able for industrial purposes in Northern Ontario in late 1958. Acceptance of natural gas, as a source of energy by the industry of that area, has been both widespread and gratifying. The mining industry of Northern Ontario has in-creased its annual use of natural gas by approximately 35 per cent each year since 1958. We believe that this trend will continue, al-though we will probably have to accept a more modest 10 per cent annual gain as the market approaches saturation. I would like to explain how we were able to do this and where all this gas is used. Our first sales were largely a matter of price-and the savings we offered were substantial."

Jan 1, 1966