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By P. Maltby

"Smelter Feed Preparation Falconbridge Nickel Mines Limited, Sudbury Operations, operate 4 mills and a smelter to produce Bessemer Ni-Cu matte for refining in Norway. Approximately 1400 tons of Ni-Cu concentrate are produced daily which are dried from a filter cake containing 14% moisture to 7.5% moisture pellets. Concentrate drying is done by 4 rotary dryers as shown in the 'Dryer Performance Data' at four separate locations. The dryers all form part of the feed preparation stage prior to sintering.The rate at which concentrate can be produced through the Sinter Plant largely depends on the quality of the dried product which makes up the feed. A feed consisting of mostly hardened pellets will sinter much faster than a feed which consists of broken pellets and dust. Dryer products require:1. Good green strength to survive shipment and handling.2. Correct moisture content.3. Sizing within a range ideally from 1/4"" to 10 mesh in diameter.Dryer performance data is shown in Table 1. Capital costs between the two types of dryers are comparable with the Roto-Louvre producing generally a larger better-formed pellet. Dryer feeds differ in that at both Hardy and Fecunis, Ni-Cu concentrate filter cake is the only feed while at the Falconbridge slurry plant the dryer feed can consist of up to 10% by weight of smelter flue dust resulting in a combined concentrate-dust pellet for feeding to the Sinter Plant. To the Falconbridge Sinter Plant dryer, dust and limestone are added for the smelting process in addition to Ni-Cu concentrate."

Jan 1, 1972

By Chris M. Healey

"The Jasper Gold mine in northern Saskatchewan produced a total mill feed of 140 127 tonnes at an average grade of 19.0 g/t Au. Both diamond drilling and chip samples from underground workings returned extremely high values, up to 12851 g/t (375 oz/T) Au over 0.10 meter from a chip sample. In the presence of such extremely high grades, the accurate estimation of reserves is a major problem.In the first part of this study, production data from the mine were used to evaluate the results of a variety of reserve estimation techniques in this environment. In two out of three cases studied, indicator kriging with assays cut to 342.9 g/t (10 oz/T) gave extremely good results. In the third case, however, indicator kriging gave unacceptable results. Instead, lognormal kriging of uncut data gave the best results.Secondly, from the same database, a number of drill-hole spacings were simulated, and reserves estimated from the simulations. As may be expected, the results of this analysis show increasingly better results with tighter drill-hole spacing. However, even with a 5 m by 5 m spacing the variation from actual grade was quite large. This is not a systematic under- or over-estimation of grade, rather a random scatter of results.The results of this study show very clearly the problems of deriving good estimates of reserves when extremely high-grade samples are encountered. There is a high degree of randomness to this data base, so reserve estimation in this situation will remain a high-risk operation."

Jan 1, 1993

By Christopher McElman

Real-time mine management solutions have evolved over time from closed, proprietary solutions, to a "system of systems" that may include a wide variety of off-the-shelf components and technologies. Modular Mining Systems has embraced open standards for their NextGen products to bridge the technology gaps between these systems. However, the remaining logical gaps must be overcome, in order to achieve truly seamless integration between discrete systems. When dealing with volatile real-time management problems, the effectiveness of business process modeling and middle-ware can break down. Scientific principles of military command and control applied to mining domain help to achieve better alignment and reach the highest level of integration. The combination of open standards and off-the-shelf hardware and software with a deliberately structured command-and-control approach provides a clear evolutionary path from ad-hoc connected systems towards real-time management of a seamlessly integrated digital mine.

Oct 1, 2009

By E. Marcotte

"Technology developments and improvements are imperative to maintain a viable mineral processing industry. In order to achieve optimum implementation of technology in processing plants, safety conscious and efficient work forces are required. Effective management methods are required to prevent employee injuries, equipment or environmental damage and process losses. Good leadership also provides for employees to perform their work in the safest and most efficient manners to attain optimum recoveries of the valuable minerals and produce high quality mill products. Equipment and processes must be designed, operated and maintained as required to assure safe and efficient mineral processing.INTRODUCTIONThe Canadian mining industry must contend with many challenges to attain and maintain a competitive position in today's global market. Canadian Mineral Processors play a vital role in meeting the challenges and achieving optimum mineral productivity.Ongoing technology developments and improvements continue to be imperative to maintain a viable mineral processing industry. The efficient implementation of technology developments requires a safety conscious, skillful and productive work force.In addition to technical and human resources, challenges may also include governments, labour unions or environmental advocates who at times may appear to be misguided or unrealistic. Canadian Mineral Processors must not allow themselves to be overwhelmed by these apparent obstacles but must use their demonstrated ingenuity to achieve successful solutions.It should be recognized that the majority of the Canadian work force are, in fact, a potentially talented and skillful people with ambitions to excel. As leaders of people, we must provide the methodology, incentive and direction that will allow our work forces to realize their ambitions. If the potentials of our work forces are not recognized and leadership is not properly exercised much loss will occur. That is, safe effective and efficient work will not be achieved."

Jan 1, 1993

By P. Hickey, A. Oliver

"In March 1993, Ram Raising Limited was faced with a challenge. Placer Dome Incorporated, Dome Mine Division requested from Ram Raising that they design station excavation into the existing No. 8 shaft from No. 3 mine levels. This work had to be done without loss of production time in the underground department.Due to the time frame of the project, every detail had to be carefully considered, with extra care that all pros and cons had been worked out.Ram Raising submitted a work Plan that had been worked out with the Redpath Group which included the infrastructure requirements; the engineering design; the scheduling and sequence of work; and the excavation design and blasting procedures.A proposal was' put together by both Ram Raising and Placer Dome outlining the infrastructure requirements, including the engineering design, scheduling and sequence of the work, excavation design and blasting procedures. The proposal accepted by Placer Dome and, on July 3D, 1993 work commenced to breakthrough eight stations. Work continued until December 1993 with the completion off our stations. The project was then stopped to allow the station access drifts from No.3 mine to be completed. The second phase of the project began on May 27 and was completed on September 15, 1994.This paper shows how, through innovative design and the full cooperation between client and contractor, a project of this nature can be completed successfully."

Jan 1, 1995

By George Dogbe

Open pit optimization forms the basis of mine design, production planning and construction of mine facilities. The negative effects of this phase may include substantial reductions in ore recoveries, relocation of waste dumps and surface infrastructure, extraction of unwanted waste, with a cumulative effect on mine value reductions. As a result, this area has received significant research focus using linear and dynamic programming, heuristic, genetic and stimulation algorithms and the graph theory. These algorithms are derived from rigorous mathematical models, but they are built on the assumption that all the periodic production capacities are extracted at the time of analysis. This assumption weakens the models because mining occurs over significant time period. In order to develop a comprehensive model that accounts for the timing of material extraction, the current models, which are built on the economic block value (EBV) concept, must be modified to account for time. In this paper, the authors develop a model of the optimization problem using the 2-D Lerchs-Grossmann?s optimization algorithm. This model is used to investigate the effect of periodic discounting on the optimal pit layout design by designing an integrated pit optimiser (IPO) that incorporates ?production scheduling?. IPO uses the ensuing discounted economic block value (DEBV) as a basis for the pit optimisation process. The time-dependent model is compared with a time-independent model. The results show that discounting has no effect on the optimal pit contour although the reported pit value is overstated if the EBVs are used instead of the DEBV. The authors, however, believe that this conclusion may not be general and could have been influenced by the nature of ore body geometry and the proposed mining strategy.

May 1, 2004

"Since all gold mills must sooner or later be cleaned up for permanent shutdown it was felt that a record of what was done at one mill might be of some help to those who will have to do the same job in the future,In cleaning up the mill of Delnite Mines Limited, I had an advantage that most mill superintendents will not have in that I started up the mill and was there until it was shut down, It was also known for two years approximately when the shutdown would be and for a year almost the exact time. This, of course, made careful planning possible and enabled me to get advance information that wouldn't have been available had the shutdown come unexpectedly,Early in 1964 calculation of ore reserves and the known number of working places available indicated that the mine would run out of ore sometime in August or September but not later than October, The time of course would vary with the number of competent miners that could be retained until the shutdown. Since the mining method used exclusively on the ore then remaining was cut and fill, it was known that once mining operations ceased it would require at most two days to crush and grind the last of the ore.In March 1 964 I took samples of the concrete floor under the precipitation presses, in the flux room and furnace room of the refinery and from the assays obtained proved that there would be no profit in breaking up the concrete to recover the gold from it, Samples taken from the top half inch of the concrete floors assayed less than 0, 10 oz per ton,"

Jan 1, 1966

By M. Falutsu

"The PSI-200 is a rugged, innovative, and easy to install on-stream size analyzer. Its calibration is simple and can be done on-line, during operation. Two measurements are displayed on the panel, which are expressed as percent passing a selected size, or as any statistical diameter. These two measurements are given as two continuous 4-20 mA output signals. Operation alarms are displayed on the screen or are given as digital output signals.The PSI-200 has been used in various applications at Lakefield Research. Particle sizes ranging from 10 µm to 450 µm have been monitored successfully, with an accuracy of 1- 2%. Having the size measured continuously and reliably, optimum conditions have been established for the grinding circuit, resulting in a superior quality in pilot plant testing.INTRODUCTIONThe challenge of any operating plant is to optimize product quality, maximize throughput and minimize operating costs. The importance of particle size measurement at a grinding circuit is well recognized. Monitoring continuously the particle size and keeping the product as uniform as possible is crucial to the whole mill operation regardless of the nature of the operation.Various techniques and instruments have been developed over the years attempting to give reliable on-line size analysis data. The operating difficulties and the reliability of these equipment still present major drawbacks and none of them proved to be widely accepted.PSI-200 is a relatively new on-line analyzer. The operation is simple and of low cost and the maintenance required minimal. It measures particle size and it displays two parameters of the solids size distribution, either weight fraction of passing a certain size or any statistical diameter. Two analog outputs can be sent to a process control system and through a supervisory control loop the correct action can be taken to maintain the desired particle size (perhaps adjust the feed rate to the grinding mill)."

Jan 1, 1993

By G. Gagnon

"HistoryMining of the Schefferville iron deposits began in 1954 on completion of the 357 mile railway linking the mines and the St-Lawrence river port of Sept-Iles. Apart from crushing, no treatment of these ores was required before smelting. In the late 1950's, testwork began at schefferville to develop a process for upgrading the extensive lower grade deposits containing 51% iron with 15% silica (natural analysis). Engineering for a six million ton per year beneficiation plant using cationic silica flotation and the A-C grate kiln Began in 1970 and the first pellets were produced in mid-1973.Production requirements and operating difficulties have restricted capacity to approximately 85% of design but on going improvements are being made continuously to attain design capacity.GeologyThe sedimentary ore bodies of the labrador trough occur in a belt 5 to 10 miles wide and 60 miles long and contain 51 individual deposits varying in size from 1 and 60 million tons. The ores are classified into three main color groups."

Jan 1, 1981

By G. E. Rodger, R. Jugoon

"SUMMARYSamples of Aunor gold precipitates which varied widely in gold content were fluxed to produce a bisilicate slag with various oxidizers and combinations of oxidizers. On the basis of some preliminary tests a flux composition was chosen which appeared to show the most promise.The different components of this flux were then incorporated into a matrix for a 23 factorial design experiment to determine what were the most important variables and what changes should be made to the flux composition to optimize the resultant total bullion fineness.The results of the 23 factorial design experiment showed that the flux composition as calculated was very close to an optimum as only very minor changes were required to give bullion in excess of 995 fine.INTRODUCTIONEarly in 1969 the results from the Aunor Gold Mines refinery showed that wide variations existed both in precipitate grade and in total bullion fineness. An analysis of this data showed that as the precipitate grade increased, the gold bullion fineness also increased (see appendix 1). Therefore, to improve the refinery results test work was initiated to: 1) improve the precipitate grade and 2) to determine, with the help of statistics, a flux composition which would be able to handle wide variations in precipitate grade and give a total bullion fineness in excess of 950 fine."

Jan 1, 1970

By Colin E. Dunn

Abstract-Plants have a remarkable ability to select, use and store metals derived from the substrate. Each species is unique in its requirements for and tolerances to the full spectrum of chemical elements in the Periodic Table. Studies to define the chemical characteristics of common trees and shrubs of the temperate forest are providing insight to their use for exploration, i.e., biogeochemical exploration. Examples of surveys over gold deposits in British Columbia show the effectiveness of sampling various tissues from different species in a range of biogeoclimatic environments. At the Nickel Plate mine in the Montane-Spruce zone, outer bark of Lodgepole pine was effective in defining a large area of metal enrichment; at the Carolin mine in the zone of Coastal Mountain Hemlock, analysis of twigs of western hemlock and Pacific silver fir provided an exploration target considerably larger than that defined by lithogeochemistry; at the Mount Washington gold deposit in the Mountain Hemlock zone, twigs of mountain hemlock and rhododendron were used to outline the mineralization; and in the Interior Douglas-fir zone at the QR deposit analysis of Douglas-fir tops collected by helicopter provided a rapid and effective method of identifying a gold-rich area.

Jan 1, 1995

By R. Pérez, James A. Finch, F. Tavera, Cesar O. Gomez

"Gas holdup is a variable which affects the operation of flotation columns. On one hand, gas holdup is a function of bubble size (a function of sparger type, frother characteristics and concentration, and air flowrate), tailings flowrate, solids content, and mixing patterns in the collection zone. On the other, gas holdup defines flotation kinetics and carrying capacity. Therefore, gas holdup is a useful variable to control and diagnose the operation of a flotation column, but the lack of a reliable sensor for on-line gas holdup monitoring has prevented its use in industry.This work describes the principle and the practical difficulties associated with the development of a gas holdup sensor based on the measurement of the electrical conductivity of dispersions. Two different approaches have been devised. These approaches will be described and test results presented of prototypes in laboratory and industrial columns.Background.Several years ago, a research program was initiated at McGill to use electrical conductivity as the basis for developing sensors for process measurements in mineral processing. Electrical conductivity is an intensive property which is a function of the concentration of the different phases present in a dispersion. The initial focus was on the detection of the interface between two dispersions with different characteristics (i.e., that between the collection and froth zones in flotation columns or that between clear water and sedimented solids in thickeners). The technique works in this case by searching for the location at which a sudden change in specific conductivity occurs, as a consequence of different gas holdup or solids content, and absolute values of the specific conductivity of the dispersions involved are not necessary1,2."

Jan 1, 1995

By Colin E. Dunn

Plants have a remarkable ability to select, use and store metals derived from the substrate. Each species is unique in its requirements for and tolerances to the full spectrum of chemical elements in the Periodic Table. Studies to define the chemical characteristics of common trees and shrubs of the temperate forest are providing insight to their use for exploration, i.e., biogeochemical exploration. Examples of surveys over gold deposits in British Columbia show the effectiveness of sampling various tissues from different species in a range of biogeoclimatic environments. At the Nickel Plate mine in the Montane-Spruce zone, outer bark of Lodgepole pine was effective in defining a large area of metal enrichment; at the Carolin mine in the zone of Coastal Mountain Hemlock, analysis of twigs of western hemlock and Pacific silver fir provided an exploration target considerably larger than that defined by lithogeochemistry; at the Mount Washington gold deposit in the Mountain Hemlock zone, twigs of mountain hemlock and rhododendron were used to outline the mineralization; and in the Interior Douglas-fir zone at the QR deposit analysis of Douglas-fir tops collected by helicopter provided a rapid and effective method of identifying a gold-rich area.

Jan 1, 1995

By S. Koppalkar

ABSTRACT: The development and evolution of the gravity recoverable gold (GrG) test procedure at McGill university is reviewed in this paper. Since the late 1980s, the research group led by the late Professor André Robert Laplante at McGill university has undertaken fundamental studies and applied research of the Knelson concentrator to develop a sustainable method of estimating GrG. Historically, a concept of “free gold” was used, and it was de?ned as the gold that could be separated and recovered from gold ore by amalgamation. Due to health and safety hazards, the practical use of amalgamation has declined. around 1994, a methodology using a 3-in Knelson concentrator to measure gravity recoverable gold was established at McGill university. as a result of more than 10 years of improvement and optimization, this technique has become a standard method of evaluating GrG for gold ores, gold plant streams and platinum group metals. By 2006, about 200 GrG tests were carried out at McGill universityon ores from all over the world. recently, a modi?ed version of the GrG test (a simpli?ed test) was developed to provide a quick and rough estimate of the GrG in a sample; this simpli?ed test has theadvantage of reduced mass, processing time and cost. to recognize and honour the contributions madeby the late Professor Laplante towards the establishment of a standard test procedure for assessing gravity recovery potential, the authors propose that the GrG test be named after Laplante.

Jan 1, 2010

By M. Timberlake, A. J. Jonaitis

"The DENVER Tube Press is a simple, high pressure (1500 PSI (100 bar)) filtration unit, developed for processing difficult-to-dewater materials and to produce a handleable filter cake and clear filtrate product.Lab and Pilot testwork conducted in Australia on coal fines (55-70% -35 micron (400 mesh)) have shown that total moisture contents of less than 20% are consistently achieved in the final cake products from the Tube Press.currently, these coal super fines are sent to waste due to uneconomical mechanical dewatering methods, which were only able to reduce total moisture levels in excess of 30%. Calculated, throughput rates for the 500 series Tube Press exceeded 1700 kg/hr (3750 lbs/hr). Feed solids concentration requirements are between 45 and 50% to achieve these results.INTRODUCTIONThe DENVER Tube Press is an automatic membrane high pressure filter press, which operates at hydraulic water pressures up to 1500 PSI (100 bar). The Tube Press was developed in the late 1960's by Charlestown Engineering, st. Austell, Cornwall, England, formerly a division of English China Clays, Ltd., to address more effective methods of moisture reduction of micron-size china clays. The Tube Press reduced moisture sufficiently to produce a hard surface-dry, handleable cake and clear filtrate discharge, which was recycled into the process. This development work was conducted using a 200 Series Tube Press (200 mm diameter x 2500 mm long filter surface)."

Jan 1, 1993

By Robert W. Baker

"Brunswick Mining and Smelting commenced production at the No. 12orebody, a lead/zinc/copper/silver deposit, situated some seventeen miles southwest of Bathurst, New Brunswick, in 1964 at 4100 tonnes per day. Today it operates at 10500 tonnes per day.Brunswick has utilized underground incentives since commencement of operations. Early incentive systems were “off the wall"" based on those in effect at other properties then manipulated to fit, often hack calculated from actual performances to tm1ve at the desired result. If subsequent payouts were considered too high the rates were simply reduced, often retroactively. A large amount of this was' subjective and depended to a large extent on whoever was handling the bonus, in conjunction with senior mine department staff.In 1971, it was' decided that a more scientific approach was needed, particularly with the introduction of the new cut-and-fill mining. After some research, a system based on Work Study was selected. Another major mining company employing such a system loaned one of their experienced employees to train some Brunswick personnel in the art of Work Study and conversion of data to incentive rates, and in 1972, the first such developed incentive rate was-introduced.Along the way, borrowing from others where necessary, a set of Brunswick principles and parameters were developed. While refined to some extent, these remain basically the same today.Improvements in methods and equipment have resulted in improved performance and reduced costs. The use of underground incentives has played an important role in this. A/though individual bonus earnings have steadily increased, bonus cost per tonne has remained nearly constant - in real dollars, it has regularly decreased. These are two of the main parameters of a successful system."

Jan 1, 1995

By W. Andrew Falls

Although we have yet to reach the midway point in the decade, the copper concentrate market has already witnessed some of the most volatile swings in history, moving from record high treatment and refining charges in 1991-92 to historic lows, in real terms, during the past year. What has been the cause for such volatility? By and large the swings can be attributed to factors of supply and demand in the "custom" copper concentrate market. For example, two relatively recent events which had a major impact on the supply-demand balance were the shutdown of the Bougainville copper mine in Papua New Guinea in 1989 due to rebel insurgency and the startup of the La Escondida mine in Chile in 1992. The first event, threw a balanced to slightly surplus concentrate market into a substantial deficit, forcing treatment terms down as smelters, caught short by the loss of concentrate supplies scrambled to cover their positions. The second event, brought over 300,000 mt per year of new copper in concentrate to the market, more than reversing the losses from the Bougainville shutdown. In combination with other additions to mine capacity via new mines or expansions, the custom concentrate market moved into a huge oversupply in 1991-92 and many mines found themselves unable to place uncommitted tonnage. But even this event was quickly overcome by the use of underutilized capacity at non-traditional buyers, such as those in the C.I.S., Zambia, or those which were not traditionally buyers of custom materials. All of this has happened in the space of five short years, a mere snapshot in the history of the market. I'll return to these points a little further on, but first I would like to review the fundamentals which govern the copper concentrate market.

Jan 1, 1995

By G. R. Yourt

"Generally speaking the usual approach for controlling dust is three-fold:1. Suppress the formation of dust at the source.2. Confine dust that cannot be suppressed.3. Dilute and remove dust that cannot be confined.This discussion will be concentrated on the second approach, namely, confining and disposing of dusty air.Dust BehaviourBefore delving into actual design principles a brief discussion on behaviour of dust should be helpful. For prevention of silicosis only respirable dust, ranging in size from < 0.5 to 5u needs to be controlled. As particles of this size have insignificant mass and momentum they follow air movements very closely. Consequently if contaminated air around dust sources is confined within enclosures and leakages maintained, strongly indraft dust is automatically controlled and capture velocities are of no concern.Dust SourcesAt metal mining operations ore is prepared for wet concentration by crushing it to mostly <3"" in size. This usually involves a jaw crusher, one or two cone crushers, one or more screens and several conveyors. Dust is actually produced only by the crushing action but it is liberated also when numerous fine particles contained in the ore stream are dispersed by surges and vibration at the discharge of the crushers, screens and headpulleys of conveyors. Furthermore, dust is dis¬persed when the slime adhering to the underside of the return portion of belts becomes dry and is rendered airborne by vibration and by cleaning floors especially where the slime has dropped."

Jan 1, 1971

By J. C. O'Rourke

"Gibraltar Mines Ltd. has been operating its open pit copper mine for fifteen years. In that time over 140 million tons of waste and low grade material has been placed on the mine waste dumps. Laboratory and in-situ testing indicated that enough leachable copper was recoverable from the dumps to justify a leaching operation which would include the construction of a solvent extraction-electrowinning plant. The plant, which was commissioned in October, 1984 was designed to process 3,000 usgpm of dilute copper solution to produce 5,000 tons per year of high quality cathode copper.This paper deals with the start up and initial year of operation of Gibraltar's SX-EW plant. The three areas: leaching solvent extraction and electrowinning are presented with emphasis on the innovations which were made to help overcome the problems unique to die Gibraltar operation.THE LEACHING CIRCUITThe mines waste dumps are leached to produce a pregnant copper solution as feed to the SX-EW plant. To achieve this the dumps are sprinkled with a mildly acidic solution which percolates through the dump. In travelling through the dumps the solution contacts the surfaces of the liberated copper minerals and disolves the soluble copper into the form of copper sulphate. The leaching reaction is achieved by a combination of bacterial action to oxidize the suphides and solublization of the copper into the acid solution.For the bacterial action to occur the dumps must be at or near the ideal pH of 1.9 - 2.1 and the necessary elements of the reaction must be present. Because a bacterial reaction is involved there is a lag time between the time when the conditions for bacterial growth are achieved and when the bacteria are in their active growth phase. Laboratory tests with Gibraltar ore indicated that bacterial action takes two to three months to reach its maximum rate. See figure 1.The expected lag time for the planned rate of bacterial leaching prompted Gibraltar to start irrigating the dumps in late June 1986 for a plant start up in early fall. The lag time proved to be longer than expected and the dumps took until November to start producing copper at the expected rate. See figure 2."

Jan 1, 1988

By O. Moselhi

Material can be seen as the fuel needed to execute the project from inception to completion. Material installed provides good indicators of progress achieved onsite vis-a-vis project schedule performance. It correlates well with the role of the schedule performance index (SPI) of the earned value method (EVM). Material is recognized to have a significant impact on achieved progress for physical completion of project activities. This paper presents a study on the development of material status index (MSI) in support of the EVM. Unlike the SPI, the newly developed index account for the criticality of project activities. This is carried out considering the total float of each activity, percent float (i.e. the ratio of float to activity duration) and the total float of the path on which the activity is located. MSI, can independently and jointly with SPI provide root causes behind problems encountered during project execution. In turn MSI can reveal material related factors behind the performance detected by joint interpretation of the two indices. MSI serves to provide added value in alerting management to take corrective actions. While SPI and MSI may have different values, they can jointly augment and enrich the captured project status based on EVM. To demonstrate the capabilities of the developed MSI method, it is implemented on a case study. The case encompasses the construction schedule of a hydro power station constructed in northern Quebec. Different scenarios are adapted from the real case to demonstrate a set of practical aspects of the developed index. The results generated from the analysis of the case study illustrate the useful features of MSI beyond those of the traditional SPI on two fronts; causation and the considerations of criticalities of actives.

Aug 1, 2013