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By H. J. Ni, M. Y. Huang, S. W. Chen

The effects of several fluxes on purification, microstructures and properties of A00 aluminium have been studied. The experimental results and analyses indicate that many cracks and large porosities exist in the surface film above the melt purified by C2Cl6 and that the film is floe and mostly composed of AhO3 and pure aluminum, which carries many carbon particles and AlCh not fully volatilized. And then over 50% of the all-melting residue is pure aluminum, which is one of the major reasons for high melting loss. Moreover, because of a mass of gas bubbles and a state of seethe, there exist many inclusions which size is under l0µm in the microstructure of A00 aluminum purified with C2Cl6 or fluxes containing C2Cl6- With this purifying method, the aluminum crystal grains are extended along the radius that was observed firstly and the average crystal size of A00 aluminum are about 100µm~150µm. In addition, small size inclusions have little affected on tensile strength and micro inclusions under l0µm have little affected on elongation.

Jan 1, 2006

By M. R. MacIver, M. P. Pawlik

"An image analysis method based on chord length distributions is applied to the batch settling of polyacrylamide flocculated kaolin suspensions. Two features of the interaggregate void space, the void chord length distribution mean and the white-to-black distribution ratio are extracted from an image series obtained over the two hour settling experiments. This approach produces three signal values, from two different probability distributions that can be measured as an indication of underlying sediment bed density and aggregation state. Further work is required on the physical interpretation of the signal, the image acquisition conditions, and the parameter selection methods. It is suggested that this chord length based feature extraction technique may be a useful signal to monitor during batch settling or thickening.INTRODUCTIONFew in situ techniques are available that can be used to directly measure aggregate properties within sediment beds in thickeners or secondary settlers. Typical process variables monitored include rake torque and height, bed level and pressure, feed rate and density, underflow rate and density, settling rate, and overflow turbidity; yet these process variables are only weakly related to process dynamics (Concha et al. 2014). Additional process monitoring signals, based on the direct measurement of aggregate properties could improve solid-liquid separation control and allow the extraction of more detailed information from batch settling experiments.Several optical methods exist for measurement of moving suspensions of aggregated solids in the dilute concentration regime, such as focused beam reflectance measurement (Peng and Williams 1994), and the turbidity fluctuation method (Gregory 1985). In the more concentrated region of a thickener, acoustic backscatter penetration and attenuation measured with an acoustic probe and changes in the underlying solid concentration in the highly concentrated, near-bed region of a thickener as a function of height and time (Hunter et al. 2012). While machine vision for froth monitoring has been thoroughly studied with at least five commercialized technologies (Aldrich et al. 2010), its’ application to the study of thickening has been limited."

Jan 1, 2016

By Martha Gellner, Lutz Wuschke, Hans-Georg Jackel, Urs A. Peuker

"Electric vehicles are an alternative to the existing combustion engine driven cars. According to the EU Battery Directive a substantial recycling rate of at least 50 wt.-% has to be met for aged batteries since 2006. Existing recycling techniques are based on energy intensive pyro- and hydrometallurgical process, which are not able to recover all components. Aluminum and lithium for instance are slagged. The EU-Project “ABattReLife” investigated possibilities for a mechanical processing in order to create a sustainable process and a closed material loop from grave to cradle. After a sufficient liberation of the Li-ion batteries, components like the doped carbon black fraction (mainly lamination of electrode foils), the separator foil and the housing material can comparatively easily be separated from the other components by screening and air sifting. The remaining mixture consists of anode and cathode foils which have a similar free-settling ratio and are more difficult to separate from each other. A second comminution and compaction step modifies the particle size and shape as well as the degree of delamination. These changes influence the density of the electrode foils in order to improve the separation efficiency. Yield and purity of the generated metal concentrates were parameters to show if the separation was successful. The specific energy consumption for the different methods of processing was estimated in order to benchmark the cost-benefit ratio for each one.The studies have been accomplished with a zig zag sifter (model TUBAF), a hammer mill (model HM 340 Jehmlich) and with a Petkus-Sifter. Finally a process flow sheet was developed for a Li-ion battery recycling plant in pilot scale."

Jan 1, 2016

By H. D. S. Miller

"This paper introduces a new approach for the design of rib pillars. The approach involves an empirical method for pillar design and a discussion of the pillar stability used for open stope mining methods.The empirical method predicts the degree of stability of rib pillars. Pillar load is estimated using two and three dimensional numerical modelling. Rock strength and the shape effect of pillars are used to account for pillar strength. The method has been calibrated with case histories from Canadian open stope metal mines and is compared with other methods used [or pillar design.INTRODUCTIONThe role of rib pillars in open stope mining is to provide stability to a mining block by limiting rock mass displacements and restricting the exposure of a rock mass in stope backs and stope walls. They also provide flexibility in ore extraction by dividing a stope block into multiple working faces.The use of backfill in open stope mining methods has reduced somewhat the need for optimum pillar design. In contrast to permanent pillar methods, the dimensions do not need to be minimized because the pillars are usually recovered in a later stage of mining. However, the consequences of poor pillar design are often overlooked and can still be severe. A pillar that does not perform its intended role may result in excessive stope or pillar sloughing, difficult and expensive pillar recovery, loss of permanent access and remedial costs such as development rehabilitation, artificial support or low productivity.Pillar design concepts of the past were not developed for open stope mining conditions and generally have not been confirmed for open stoping. The focus of this paper is to introduce an empirical design relationship specifically for open stope pillars. It provides a stable, yielding or failed pillar assessment for a given design."

Jan 1, 1989

By T. Junne, L. Eltrop, S. Moreno-Leiva, J. Haas, W. Kracht

The energy systems of the future will be highly renewable. The flexibility that is consequently required can be provided with many options, the main ones being energy storage, transmission reinforcement, and demand side management. The role of the latter is explored for the copper industry, using the scheduling of maintenance services as an example of Solar-Paced Design - the coupling of energy demand with solar resource availability. We used a linear energy optimization model to define the minimum-cost configuration for a fully renewable energy system of a copper concentration plant under different scenarios for the scheduling of maintenance services. For the case we studied, (total) costs were 4% lower when the maintenance was scheduled in winter. We expect that exploring the potential of such Solar-Paced Design in the copper industry will allow new potentials for a more cost-effective full renewable energy supply of this critical industry. INTRODUCTION The mitigation of climate change requires a worldwide transformation of the energy system by the significant expansion of renewable energies and the electrification of various sectors and processes (Teske et al., 2015)(International Energy Agency IEA, 2018). Moreover, considering the decreasing costs of renewable energy technologies and the intensive use required to deliver the goals in the Paris Agreement, we can expect to have highly renewable energy systems in the near future. However, to rebuild and expand our energy systems, we need certain materials, including copper. Also, energy systems based on renewables are more copper-intensive than conventional ones (Kleijn, van der Voet, Kramer, van Oers, & van der Giesen, 2011). The mineral industry, in turn, needs clean energy to achieve a better environmental performance (e.g. solar energy for copper production (Moreno-Leiva et al., 2017)) and to avoid negative secondary effects induced by the strong expansion of clean technologies. But there is something else the minerals industry can offer in this bi-directional relation with energy systems.

Jan 1, 2019

Gold recovery from refractory ores can be very difficult and complicated depending on the causes of the refractoriness. Typically, a fine wind and/or the oxidation of the gold-bearing sulfide minerals are required to liberate gold from the host rock matrix. Mineral separation techniques, particularly surface¬wettability based separation (i.e., flotation) and magnetic separation, can be used to pre-concentrate the gold and sulfide minerals, or to remove mineral species that are harmful either to the oxidation of the gold-bearing sulfides or to the cyanidation following the oxidation. In this paper, several processes are described, including oil-agglomeration flotation recovery of fine-grained gold and sulfide, reverse flotation of carbonate minerals prior to pressure or bio oxidation, reverse flotation of elemental sulfur after pressure or bio oxidation but prior to cyanide leaching, and magnetic concentration of gold-bearing iron oxides. The integration of these techniques with gold hydrometallurgical processes may make the economic recovery of gold from an otherwise uneconomic refractory ore possible.

Jan 1, 2011

By R. C. Beard

"The Ontario Ministry of Natural Resources has recently initiated several incentive programs to encourage and facilitate the development of new mines in northwestern Ontario. Some are privatized out to consultants and contractors. The status of three of these programs will be reviewed in this paper.IntroductionOne of the main objectives of the Mineral Resources Group of the Ontario Ministry of Natural Resources is to encourage and assist mineral exploration and the development of new mines in the Province. Programs to accomplish this objective are largely carried out through two Branches in the main office (in Toronto), the Mineral Resources Branch and the Ontario Geological Survey, and also a number of regional field offices scattered across Ontario.The function of the Mineral Resources Branch is to identify and administer effective policies that will ensure maximum benefits to the Province from mineral resource extraction.One of the most important factors in ensuring effective exploration in the Province is the availability of a good geosciences data base from which to work. It is the responsibility of the Ontario Geological Survey to develop and continually update this data base, providing, to both the public and private sector, an inventory and analysis of the geology and mineral deposits of the Province.The main functions of the regional field offices are to provide technical data and advice to exploration companies and prospectors, to encourage and assist exploration, and to provide information and general assistance to producing and developing properties to facilitate resource development and extraction. This is accomplished through the offices of the mineral resource coordinators and resident geologists. In northwestern Ontario, these field offices are located at Thunder Bay, Kenora, Red Lake and Sioux Lookout.To accomplish their objectives, the Ontario Geological Survey and the regional field offices carry out regular, ongoing geoscience and other mineral resource programs, under their base funding."

Jan 1, 1982

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 H. E. T. Haultain

Research is a much over-overworked word, sometimes a much abused word; the result of this has been that many who really need the word avoid it, shy away from it just as we do from that most useful word camouflage. We have not been altogether happy in our substitutes. Some years ago I spoilt a very good proposition by using the word investigation. There were those who thought that men and methods were to be investigated instead of simply processes. They expected disruption instead of co-ordination. The bad psychology up-set the scheme. The word experiment is even worse in its psychology. To the mind of the "practical" business man experiment denotes ignorance, waste of time and money and presupposes failure. It is not so long ago that the recognized way of improving the methods about a mine was to get a new manager. Until comparatively recently the average life of a boss in a mine in the West was under, rather than over, two years. Certainly was this the case in the smaller mines. Directors did not recognize that a cock-sure new boss was a greater experiment than a certain amount of feeling-his-way on the part of the old one. We always say that no two mines are the same but we are only now realizing to what extent the fine points of the game can and must be learnt on the job itself. One of the main differences between a small property and a large one lies in this study of the fine points of the game. In the early stages operation is the main point-get her going and keep her going.

Jan 1, 1924

By Fernand Dubuc

"The New Pascalis property is situated in Louvicourt and Pascalis townships, about 200 km east of Val d'Or, Quebec. It is made up of 38 claims under option to SOQUEM since August I, 1981 during which time SOQUEM has earned a 60% interest. The property is underlain by archean basaltic volcanics that have been intruded along the west boundary by the Bourlamaque batholith, and by north -trending dykes.The 1982 disco very is related to the re-evaluation of a 1931-gold showing located in the southeastern part of the property, a combination of the presence of a weak IP anomaly at the eastern end of the showing and overburden stripping at that location, resulted in the discovery of a mineralized diorite dyke.The dyke, which strikes N 20 ° Wand dips vertically , has intruded E-W striking agglomerates. The dyke contains south dipping, gold-hearing quart z-tourmaline-pyrite veins that are distributed in a ladder-type arrangement. Visible gold may he observed in drill core, and is generally associated with pyrite porphyroblasts.Diamond drilling has outlined th e dyke for a strike length of 300 11/ and a width of about 10 m, Result s of this drilling indicate, to a depth of 155 m, reserves of 834 000 metric tonnes grading 8.25 g Au/t un cut or 5.38 g Au/t cut to on e ounce. However, four deeper holes have added depth extension to 400m. Also, west of the dyke and within 150 m, other promising gold values have been intersected within quartz-tourmaline veins associated with other parallel dykes."

Jan 1, 1985

By P. J. Dunlop

THE object of this paper is to present a brief survey of the work done and the results obtained in controlling dust at the Hollinger Consolidated Gold Mines milling plant. The plant includes all primary and secondary crushing, grinding, and treatment operations. The major items of equipment are: (1) Underground Crusher Plant 1 48 in. by 60 in. jaw crusher, crushing run-of-mine ore to minus-6-in. Rate: 420 tons per hour (2) Surface Crusher Plant 3 No. 772 gyratory crushers 3 4 ft. by 16 ft. trommel screens 4 No. S gyratory crushers Reducing ore to rninus-172-in. Rate: 420 tons per hour (3) Roll Plant 5 sets of 62 in. bJ: 24 in. rolls 7 5 ft. by 10 ft. v1bratrng screens Delivering a minus-3/16-in. finished product Rate: 420 tons per hour (4) Grinding Plant 4 7 ft. by 15 ft. low discharge grate ball-mills 4 12 ft. reciprocating rake classifiers Rate: 4,800 tons per 24 hours Maximum capacity: S,800 tons per 24 hours

Jan 1, 1939

By J. Drelich

We report structural forces measured for 10 nm silica particles deposited on alumina substrate and 5-80 nm alumina particles on mica using atomic force microscopy technique. For nanoparticles forming clusters, oscillation of structural forces was recorded with a periodicity that is close to the size of the nanoparticles used. Additionally, selected force-separation results indicate that the forces involved between the AFM probe and individual nanoparticles can be studied using the nanoparticle-coated substrates.

Jan 1, 2006

By L. T. Raevskaia

We discuss the stability problem of a piston of the reversible axial-piston pneumatic motor called DAR-14M. We performed the full analysis of stress and deformation characteristics of the piston near a resonant frequency with the help of FEM ANSYS. We estimated the own frequency of the piston analytically for the given motor, this estimate was confirmed numerically in the model analysis FEM ANSYS. It was also shown in harmonic analysis that loaded piston end behaves very different in comparison to the unloaded end. As expected, maximum deformation was found in the area of the holes of the bearing shaft, indicating an optimization necessary in that region of the motor.

Aug 1, 2013

By J. H. Starkey, P. A. Scinto

"In Canada and other countries, legislation dealing with accurate factual disclosure for mining projects is being expanded to include more metallurgical design information. Grinding characteristics, metallurgical recovery of contained metal and environmental hazards associated with tailings disposal will be part of the Canadian package. This paper will examine only that portion of the plant design standard practice that relates to grinding – in SAG mills and ball mills that grind ore from as received crushed material to final ground product that is fed to downstream plant recovery processes. Since grinding plants represent a significant portion of the overall concentrator cost, accountability in grinding design should no longer be left to chance, opinion, or hidden proprietary information. This is the 21st century. It is reasonable to expect that a factual basis will be needed so that a Qualified Person (QP) reviewing the grinding mill design can understand it. That will also involve how many and what quality of samples are taken to define the characteristics of the deposit, the accuracy of the tests used to measure ore hardness and the method by which the dimensions and power of the mills are determined. If these criteria are not met, the QP may have no choice but to call attention to the lack of convincing information regarding the grinding mill design for the project. At the same time clients are expected to demand getting the correct design information at a cheaper price, results in a more timely way, and accurate design to the point where the risk of tonnage shortfalls are reduced or eliminated.Tables will be presented to show how this can be done to current standards using existing technologies. At the same time it is acknowledged that current standards are ill-defined and that to achieve consensus among those involved in SAG mill design work, it may require that a consortium funded project be set up to establish what tests and methods for grinding design are suitable to meet the new standards for metallurgical disclosure. By running parallel design methods on several major projects over a period of 5 years, the process of how to design grinding circuits will be better understood because the projects will start at the design stage, include procurement of the mills and will end with a benchmark test on the plant.Selecting the samples and the best schedule for doing test work on core samples submitted and mill design, will be discussed in this paper. The issue of completing the grinding design in time for early procurement decisions is on the critical path for most major projects. Discussions between mining engineers, geologists and process engineers are needed early in the development cycle, at the scoping study level (SS), preliminary engineering assessment (PEA), prefeasibility study (PFS), and at the feasibility study stage (FS), to ensure that proper planning for design sample selection is done. Using adequate sampling and testing methods in a timely way allows early procurement of the grinding mills and minimizes project risk."

Jan 1, 2012

By K. M. Ed

MR. J. C. NICHOLSON: The author has discussed his subject in a very thorough manner. One difficulty is the tendency to regard a 'permitted' explosive as a 'safe' explosive. There is no such article as a safe explosive; any explosive is only as safe as the man who handles it. In making up the primer, the method illustrated in the paper is alright for the ordinary explosive but not so for the sheathed explosive, for the sheathing would be punctured. MR. T. L. McCALL: I fee! quite certain that there would be little, if any, trouble from flame shots or misfires if the author's suggestions were carried out. There is a tendency on the part of the shot-firer to over-shoot, so as to bring clown more coal for the miner, and frequently a shot has not sufficient burden imposed upon it. Shooting one hole may not only lessen the burden on an adjacent hole, but may practically release it altogether, in which case the second hole should be fired with a very small charge, or perhaps it might not be necessary to shoot it at all. While the paper refers to shooting in the coal only, it should be under-stood that the instructions given are equally applicable to brushing shots. I do not wish to bring up any contentious point, but would the author say a word on cushioning with air gaps and on multiple shooting? Single shooting in rock might open up a feeder of gas which could be ignited by the ?second shot.

Jan 1, 1940

Most of automotive magnesium applications are presently produced by high-pressure die casting processes, For further expansion of the alloy usage in automobiles, novel-manufacturing processes needs to be developed, In this study, squeeze casting of AM50 alloy was carried out using a hydraulic press with an applied pressure of 70 MPa, Tensile properties and fracture behavior of the squeeze-cast AM50 were characterized in comparison with the die cast counterpart, The squeeze-cast AM50 alloy exhibits virtually no porosity in the microstructure evaluated by optical microscopy, The results of tensile testing indicate that the improved tensile properties for the squeeze-cast samples over the conventional high-pressure die-cast parts, The analysis of tensile behavior shows that the strain-hardening rate during the plastic deformation of the squeeze-cast specimens is constantly higher than that of the die-cast specimens. The SEM fractography evidently reveals the ductile fracture features of the squeeze-cast alloy AM50.

Jan 1, 2005

By Carmen Mihaela Neculita

Sulfate-reducing passive bioreactors efficiently treat acid mine drainage (AMD) by increasing its pH and alkalinity and by removing metals as sulfide precipitates, in addition to hydroxides and carbonates. However, the new mining legislation sets discharge limits based on physicochemical parameters and on the non-toxicity of treated effluent as well. In this study, toxicity was assessed for effluent from 3.5 L column bioreactors filled with mixtures of natural organic carbon sources and operated at two different hydraulic retention times (HRTs) of 7.3 d and 10 d for the treatment of a highly contaminated AMD. Acute toxicity was observed for D. magna, and a toxicity identification evaluation (TIE) procedure was performed to identify potential toxicants. To help the interpretation of the toxicity results, metal partition in the effluent was also determined by filtration and ultrafiltration, while geochemical modeling was performed for metal speciation evaluation. The 10 d HRT effluent was nonacutely lethal for rainbow trout but acutely lethal for D. magna, whereas the 7.3 d HRT effluent was toxic for both organisms. The toxicity to D. magna was eliminated by 2 h of aeration for the 10 d HRT effluent, and the TIE procedure suggested iron as a cause of toxicity. However, the 2 h aeration eliminated the toxicity of the 7.3 d HRT effluent, only if performed after the pH rising to 9.3. Data regarding metal speciation indicated instability of both effluents during aeration and were consistent with the toxicity being caused by iron. The study indicates that design of passive treatment should include sufficient HRT and posttreatment aeration to meet acute toxicity requirements. Keywords: acid mine drainage, sulphate-reducing passive bioreactors, hydraulic retention time, effluent toxicity, metal speciation

Nov 1, 2008

By A. -M. Cadieux

During the geological synthesis of the Réservoir Pipmuacan area (NTS 22E) by the Ministère des Ressources naturelles (Québec), several ilmenite-apatite occurrences, some well-known and some recently discovered, have been examined. These occurrences are hosted in the Lac-Saint-Jean and Labrieville AMCG anorthositic suites. The Lac-Saint-Jean Anorthositic Suite (1160-1140 Ma), composed of multiple intrusions covering an extensive surface area, is characterized by labradorite plagioclase. The Labrieville Anorthositic Suite (1010-1008 Ma) is characterized by andesine plagioclase. It was previously known as the Labrieville Anorthosite, which was composed of a small isolated pluton located east of the Lac-Saint-Jean Anorthositic Suite. However, new geochronological data and field observations indicate that the Labrieville Anorthositic Suite in fact includes several intrusive bodies, namely the La Hache Monzonite and the Mattawa Anorthosite. A series of major structures (Saint-Fulgence, Pipmuacan, and Chute-des-Passes deformation zones) and their conjugate faults played an important role in the emplacement of the Lac-Saint-Jean Anorthositic Suite. The Saint-Fulgence deformation zone appears to have been involved in the emplacement of the Labrieville Anorthositic Suite. Oxide mineralizations are abundant in both anorthositic suites. Ilmenite, magnetite (± titaniferous), and apatite assemblages are found mostly in the labradorite-type anorthosites, while hemo-ilmenite, magnetite and apatite assemblages are associated only with the andesine-type anorthosites. Field works has revealed ilmenite-apatite mineralizations in a variety of settings, with grades reaching 48% TiO2, 16.2% P2O5, and 71.7% Fe2O3 (tot). Numerous oxide-bearing gabbronorites, often accompanied by or located near massive apatite-oxide accumulations (nelsonites), were discovered. Among these oxide-rich zones, breccia zones with anorthosite enclaves in an oxide matrix (ilmenite-magnetiteapatite) have been observed. Locally, ilmenite-apatite mineralization occurs as cumulate concentrations in ultramafic rocks. Evidence has been observed for immiscible magmas, for magmas differentiated from a mangerite or jotunite parent, and even for late magmas differentiated from the anorthosite magma itself (apatite-bearing anorthosite). Finally, the northern part of the Lac-Saint-Jean Anorthositic Suite hosts sulfide and vanadium mineralizations associated with ilmenite-apatite enriched zones, with grades reaching 1.48% Cu, 1.22% Ni, 1.6% Cr2O5, 0.25% Co, and 0.52% V2O5.

May 1, 2003

By C. A. Pickles

Nickeliferous limonitic laterite ores contain considerable free moisture. In this research, the application of microwave radiation for the drying of this ore was investigated. The effects of sample mass, initial moisture content and porosity on the microwave drying rate were studied and the results were compared to those obtained with conventional drying. Microwave drying rates of two to three times the conventional values were achieved. Further enhancement of the microwave drying rate was realized by increasing the flow rate of air over the sample or by operating at reduced pressure. The high microwave drying rates were attributed to the inverted temperature gradient which resulted in internal heating and boiling and this in turn promoted movement of the water, both as liquid and vapour, to the surface.

Jan 1, 2005

By Keith C. Hendrick

"Metal prices are frequently the most critical and least predictable element in determining the profitability of mining operations. Short -term fluctuations can be offset in varying degrees by hedging or other market actions. Such solutions are not practical for the longer term, The paper investigates the nature and extent of metal price risks and evaluates methods to reduce them.IntroductionIt is management's responsibility to improve the odds by managing the-risks by identifying them clearly, assessing them accurately, minimizing them where possible-and, then, timing decision s success fully.In determining the profitability of current operations, preparing forward plan s or developing feasibility studies for new projects or expansions, pr ices are usually the most critical input. Being market determined rather than cost based, they can also be the most unpredictable As a result, commodity prices are frequently the greatest of all risk factors.Nature of Commodity PricesThe cyclical nature of commodity prices is well known. They are stable only when supply is in balance with demand and forecast to remain that way. An imbalance on either side of the equation can lead to a price reaction completely out of proportion to the actual or perceived surplus or shortage.This exaggeration arises through the cumulative effect of market forces. When the market senses an uptrend, consumers buy for the expected increase in activity. They also seek additional quantities for inventory before price s rise. Merchants defer spot sales anticipating higher price s, speculators go along for the same reason, and producers raise prices in response to demand. Events tend to confirm the expectation of each party and strengthen their reaction causing prices to move higher."

Jan 1, 1983